Sample records for discrete choice transport

  1. Choice-Based Conjoint Analysis: Classification vs. Discrete Choice Models

    NASA Astrophysics Data System (ADS)

    Giesen, Joachim; Mueller, Klaus; Taneva, Bilyana; Zolliker, Peter

    Conjoint analysis is a family of techniques that originated in psychology and later became popular in market research. The main objective of conjoint analysis is to measure an individual's or a population's preferences on a class of options that can be described by parameters and their levels. We consider preference data obtained in choice-based conjoint analysis studies, where one observes test persons' choices on small subsets of the options. There are many ways to analyze choice-based conjoint analysis data. Here we discuss the intuition behind a classification based approach, and compare this approach to one based on statistical assumptions (discrete choice models) and to a regression approach. Our comparison on real and synthetic data indicates that the classification approach outperforms the discrete choice models.

  2. Discrete choice experiments of pharmacy services: a systematic review.

    PubMed

    Vass, Caroline; Gray, Ewan; Payne, Katherine

    2016-06-01

    Background Two previous systematic reviews have summarised the application of discrete choice experiments to value preferences for pharmacy services. These reviews identified a total of twelve studies and described how discrete choice experiments have been used to value pharmacy services but did not describe or discuss the application of methods used in the design or analysis. Aims (1) To update the most recent systematic review and critically appraise current discrete choice experiments of pharmacy services in line with published reporting criteria and; (2) To provide an overview of key methodological developments in the design and analysis of discrete choice experiments. Methods The review used a comprehensive strategy to identify eligible studies (published between 1990 and 2015) by searching electronic databases for key terms related to discrete choice and best-worst scaling (BWS) experiments. All healthcare choice experiments were then hand-searched for key terms relating to pharmacy. Data were extracted using a published checklist. Results A total of 17 discrete choice experiments eliciting preferences for pharmacy services were identified for inclusion in the review. No BWS studies were identified. The studies elicited preferences from a variety of populations (pharmacists, patients, students) for a range of pharmacy services. Most studies were from a United Kingdom setting, although examples from Europe, Australia and North America were also identified. Discrete choice experiments for pharmacy services tended to include more attributes than non-pharmacy choice experiments. Few studies reported the use of qualitative research methods in the design and interpretation of the experiments (n = 9) or use of new methods of analysis to identify and quantify preference and scale heterogeneity (n = 4). No studies reported the use of Bayesian methods in their experimental design. Conclusion Incorporating more sophisticated methods in the design of pharmacy

  3. Sample Design for Discrete Choice Analysis of Travel Behavior

    DOT National Transportation Integrated Search

    1978-07-01

    Discrete choice models represent the choices of individuals among alternatives such as modes of travel, auto types and destinations. This paper presents a review of the state-of-the-art in designing samples for discrete choice analysis of traveller b...

  4. A Bayesian hierarchical model for discrete choice data in health care.

    PubMed

    Antonio, Anna Liza M; Weiss, Robert E; Saigal, Christopher S; Dahan, Ely; Crespi, Catherine M

    2017-01-01

    In discrete choice experiments, patients are presented with sets of health states described by various attributes and asked to make choices from among them. Discrete choice experiments allow health care researchers to study the preferences of individual patients by eliciting trade-offs between different aspects of health-related quality of life. However, many discrete choice experiments yield data with incomplete ranking information and sparsity due to the limited number of choice sets presented to each patient, making it challenging to estimate patient preferences. Moreover, methods to identify outliers in discrete choice data are lacking. We develop a Bayesian hierarchical random effects rank-ordered multinomial logit model for discrete choice data. Missing ranks are accounted for by marginalizing over all possible permutations of unranked alternatives to estimate individual patient preferences, which are modeled as a function of patient covariates. We provide a Bayesian version of relative attribute importance, and adapt the use of the conditional predictive ordinate to identify outlying choice sets and outlying individuals with unusual preferences compared to the population. The model is applied to data from a study using a discrete choice experiment to estimate individual patient preferences for health states related to prostate cancer treatment.

  5. A review of the application and contribution of discrete choice experiments to inform human resources policy interventions

    PubMed Central

    Lagarde, Mylene; Blaauw, Duane

    2009-01-01

    Although the factors influencing the shortage and maldistribution of health workers have been well-documented by cross-sectional surveys, there is less evidence on the relative determinants of health workers' job choices, or on the effects of policies designed to address these human resources problems. Recently, a few studies have adopted an innovative approach to studying the determinants of health workers' job preferences. In the absence of longitudinal datasets to analyse the decisions that health workers have actually made, authors have drawn on methods from marketing research and transport economics and used Discrete Choice Experiments to analyse stated preferences of health care providers for different job characteristics. We carried out a literature review of studies using discrete choice experiments to investigate human resources issues related to health workers, both in developed and developing countries. Several economic and health systems bibliographic databases were used, and contacts were made with practitioners in the field to identify published and grey literature. Ten studies were found that used discrete choice experiments to investigate the job preferences of health care providers. The use of discrete choice experiments techniques enabled researchers to determine the relative importance of different factors influencing health workers' choices. The studies showed that non-pecuniary incentives are significant determinants, sometimes more powerful than financial ones. The identified studies also emphasized the importance of investigating the preferences of different subgroups of health workers. Discrete choice experiments are a valuable tool for informing decision-makers on how to design strategies to address human resources problems. As they are relatively quick and cheap survey instruments, discrete choice experiments present various advantages for informing policies in developing countries, where longitudinal labour market data are seldom

  6. Stated choice for transportation demand management models : using a disaggregate truth set to study predictive validity

    DOT National Transportation Integrated Search

    1997-01-01

    Discrete choice models have expanded the ability of transportation planners to forecast future trends. Where new services or policies are proposed, the stated-choice approach can provide an objective basis for forecasts. Stated-choice models are subj...

  7. Protective Behaviour of Citizens to Transport Accidents Involving Hazardous Materials: A Discrete Choice Experiment Applied to Populated Areas nearby Waterways

    PubMed Central

    de Bekker-Grob, Esther W.; Bergstra, Arnold D.; Bliemer, Michiel C. J.; Trijssenaar-Buhre, Inge J. M.; Burdorf, Alex

    2015-01-01

    Background To improve the information for and preparation of citizens at risk to hazardous material transport accidents, a first important step is to determine how different characteristics of hazardous material transport accidents will influence citizens’ protective behaviour. However, quantitative studies investigating citizens’ protective behaviour in case of hazardous material transport accidents are scarce. Methods A discrete choice experiment was conducted among subjects (19–64 years) living in the direct vicinity of a large waterway. Scenarios were described by three transport accident characteristics: odour perception, smoke/vapour perception, and the proportion of people in the environment that were leaving at their own discretion. Subjects were asked to consider each scenario as realistic and to choose the alternative that was most appealing to them: staying, seeking shelter, or escaping. A panel error component model was used to quantify how different transport accident characteristics influenced subjects’ protective behaviour. Results The response was 44% (881/1,994). The predicted probability that a subject would stay ranged from 1% in case of a severe looking accident till 62% in case of a mild looking accident. All three transport accident characteristics proved to influence protective behaviour. Particularly a perception of strong ammonia or mercaptan odours and visible smoke/vapour close to citizens had the strongest positive influence on escaping. In general, ‘escaping’ was more preferred than ‘seeking shelter’, although stated preference heterogeneity among subjects for these protective behaviour options was substantial. Males were less willing to seek shelter than females, whereas elderly people were more willing to escape than younger people. Conclusion Various characteristics of transport accident involving hazardous materials influence subjects’ protective behaviour. The preference heterogeneity shows that information needs

  8. Discrete choice experiments to measure consumer preferences for health and healthcare.

    PubMed

    Viney, Rosalie; Lancsar, Emily; Louviere, Jordan

    2002-08-01

    To investigate the impact of health policies on individual well-being, estimate the value to society of new interventions or policies, or predict demand for healthcare, we need information about individuals' preferences. Economists usually use market-based data to analyze preferences, but such data are limited in the healthcare context. Discrete choice experiments are a potentially valuable tool for elicitation and analysis of preferences and thus, for economic analysis of health and health programs. This paper reviews the use of discrete choice experiments to measure consumers' preferences for health and healthcare. The paper provides an overview of the approach and discusses issues that arise when using discrete choice experiments to assess individuals' preferences for health and healthcare.

  9. Consumer Behavior in the Choice of Mode of Transport: A Case Study in the Toledo-Madrid Corridor

    PubMed Central

    Muro-Rodríguez, Ana I.; Perez-Jiménez, Israel R.; Gutiérrez-Broncano, Santiago

    2017-01-01

    Within the context of the consumption of goods or services the decisions made by individuals involve the choice between a set of discrete alternatives, such as the choice of mode of transport. The methodology for analyzing the consumer behavior are the models of discrete choice based on the Theory of Random Utility. These models are based on the definition of preferences through a utility function that is maximized. These models also denominated of disaggregated demand derived from the decision of a set of individuals, who are formalized by the application of probabilistic models. The objective of this study is to determine the behavior of the consumer in the choice of a service, namely of transport services and in a short-distance corridor, such as Toledo-Madrid. The Toledo-Madrid corridor is characterized by being short distance, with high speed train available within the choice options to get the airport, along with the bus and the car. And where offers of HST and aircraft services can be proposed as complementary modes. By applying disaggregated transport models with revealed preference survey data and declared preferences, one can determine the most important variables involved in the choice and determine the arrangements for payment of individuals. These payment provisions may condition the use of certain transport policies to promote the use of efficient transportation. PMID:28676776

  10. Consumer Behavior in the Choice of Mode of Transport: A Case Study in the Toledo-Madrid Corridor.

    PubMed

    Muro-Rodríguez, Ana I; Perez-Jiménez, Israel R; Gutiérrez-Broncano, Santiago

    2017-01-01

    Within the context of the consumption of goods or services the decisions made by individuals involve the choice between a set of discrete alternatives, such as the choice of mode of transport. The methodology for analyzing the consumer behavior are the models of discrete choice based on the Theory of Random Utility. These models are based on the definition of preferences through a utility function that is maximized. These models also denominated of disaggregated demand derived from the decision of a set of individuals, who are formalized by the application of probabilistic models. The objective of this study is to determine the behavior of the consumer in the choice of a service, namely of transport services and in a short-distance corridor, such as Toledo-Madrid. The Toledo-Madrid corridor is characterized by being short distance, with high speed train available within the choice options to get the airport, along with the bus and the car. And where offers of HST and aircraft services can be proposed as complementary modes. By applying disaggregated transport models with revealed preference survey data and declared preferences, one can determine the most important variables involved in the choice and determine the arrangements for payment of individuals. These payment provisions may condition the use of certain transport policies to promote the use of efficient transportation.

  11. Discrete choice modeling of season choice for Minnesota turkey hunters

    USGS Publications Warehouse

    Schroeder, Susan A.; Fulton, David C.; Cornicelli, Louis; Merchant, Steven S.

    2018-01-01

    Recreational turkey hunting exemplifies the interdisciplinary nature of modern wildlife management. Turkey populations in Minnesota have reached social or biological carrying capacities in many areas, and changes to turkey hunting regulations have been proposed by stakeholders and wildlife managers. This study employed discrete stated choice modeling to enhance understanding of turkey hunter preferences about regulatory alternatives. We distributed mail surveys to 2,500 resident turkey hunters. Results suggest that, compared to season structure and lotteries, additional permits and level of potential interference from other hunters most influenced hunter preferences for regulatory alternatives. Low hunter interference was preferred to moderate or high interference. A second permit issued only to unsuccessful hunters was preferred to no second permit or permits for all hunters. Results suggest that utility is not strictly defined by harvest or an individual's material gain but can involve preference for other outcomes that on the surface do not materially benefit an individual. Discrete stated choice modeling offers wildlife managers an effective way to assess constituent preferences related to new regulations before implementing them. 

  12. Using Discrete Choice Experiments to Inform the Benefit-Risk Assessment of Medicines: Are We Ready Yet?

    PubMed

    Vass, Caroline M; Payne, Katherine

    2017-09-01

    There is emerging interest in the use of discrete choice experiments as a means of quantifying the perceived balance between benefits and risks (quantitative benefit-risk assessment) of new healthcare interventions, such as medicines, under assessment by regulatory agencies. For stated preference data on benefit-risk assessment to be used in regulatory decision making, the methods to generate these data must be valid, reliable and capable of producing meaningful estimates understood by decision makers. Some reporting guidelines exist for discrete choice experiments, and for related methods such as conjoint analysis. However, existing guidelines focus on reporting standards, are general in focus and do not consider the requirements for using discrete choice experiments specifically for quantifying benefit-risk assessments in the context of regulatory decision making. This opinion piece outlines the current state of play in using discrete choice experiments for benefit-risk assessment and proposes key areas needing to be addressed to demonstrate that discrete choice experiments are an appropriate and valid stated preference elicitation method in this context. Methodological research is required to establish: how robust the results of discrete choice experiments are to formats and methods of risk communication; how information in the discrete choice experiment can be presented effectually to respondents; whose preferences should be elicited; the correct underlying utility function and analytical model; the impact of heterogeneity in preferences; and the generalisability of the results. We believe these methodological issues should be addressed, alongside developing a 'reference case', before agencies can safely and confidently use discrete choice experiments for quantitative benefit-risk assessment in the context of regulatory decision making for new medicines and healthcare products.

  13. Preferences of older patient regarding hip fracture rehabilitation service configuration: A feasibility discrete choice experiment.

    PubMed

    Charles, Joanna M; Roberts, Jessica L; Din, Nafees Ud; Williams, Nefyn H; Yeo, Seow Tien; Edwards, Rhiannon T

    2018-05-14

    As part of a wider feasibility study, the feasibility of gaining older patients' views for hip fracture rehabilitation services was tested using a discrete choice experiment in a UK context. Discrete choice experiment is a method used for eliciting individuals' preferences about goods and services. The discrete choice experiment was administered to 41 participants who had experienced hip fracture (mean age 79.3 years; standard deviation (SD) 7.5 years), recruited from a larger feasibility study exploring a new multidisciplinary rehabilitation for hip fracture. Attributes and levels for this discrete choice experiment were identified from a systematic review and focus groups. The questionnaire was administered at the 3-month follow-up. Participants indicated a significant preference for a fully-qualified physiotherapist or occupational therapist to deliver the rehabilitation sessions (β = 0·605, 95% confidence interval (95% CI) 0.462-0.879), and for their rehabilitation session to last less than 90 min (β = -0.192, 95% CI -0.381 to -0.051). The design of the discrete choice experiment using attributes associated with service configuration could have the potential to inform service implementation, and assist rehabilitation service design that incorporates the preferences of patients.

  14. Air Cargo Transportation Route Choice Analysis

    NASA Technical Reports Server (NTRS)

    Obashi, Hiroshi; Kim, Tae-Seung; Oum, Tae Hoon

    2003-01-01

    Using a unique feature of air cargo transshipment data in the Northeast Asian region, this paper identifies the critical factors that determine the transshipment route choice. Taking advantage of the variations in the transport characteristics in each origin-destination airports pair, the paper uses a discrete choice model to describe the transshipping route choice decision made by an agent (i.e., freight forwarder, consolidator, and large shipper). The analysis incorporates two major factors, monetary cost (such as line-haul cost and landing fee) and time cost (i.e., aircraft turnaround time, including loading and unloading time, custom clearance time, and expected scheduled delay), along with other controls. The estimation method considers the presence of unobserved attributes, and corrects for resulting endogeneity by use of appropriate instrumental variables. Estimation results find that transshipment volumes are more sensitive to time cost, and that the reduction in aircraft turnaround time by 1 hour would be worth the increase in airport charges by more than $1000. Simulation exercises measures the impacts of alternative policy scenarios for a Korean airport, which has recently declared their intention to be a future regional hub in the Northeast Asian region. The results suggest that reducing aircraft turnaround time at the airport be an effective strategy, rather than subsidizing to reduce airport charges.

  15. Measuring Patient Preferences: An Overview of Methods with a Focus on Discrete Choice Experiments.

    PubMed

    Hazlewood, Glen S

    2018-05-01

    There is increasing recognition of the importance of patient preferences and methodologies to measure them. In this article, methods to quantify patient preferences are reviewed, with a focus on discrete choice experiments. In a discrete choice experiment, patients are asked to choose between 2 or more treatments. The results can be used to quantify the relative importance of treatment outcomes and/or other considerations relevant to medical decision making. Conducting and interpreting a discrete choice experiment requires multiple steps and an understanding of the potential biases that can arise, which we review in this article with examples in rheumatic diseases. Copyright © 2018 Elsevier Inc. All rights reserved.

  16. Developing a discrete choice experiment in Malawi: eliciting preferences for breast cancer early detection services.

    PubMed

    Kohler, Racquel E; Lee, Clara N; Gopal, Satish; Reeve, Bryce B; Weiner, Bryan J; Wheeler, Stephanie B

    2015-01-01

    In Malawi, routine breast cancer screening is not available and little is known about women's preferences regarding early detection services. Discrete choice experiments are increasingly used to reveal preferences about new health services; however, selecting appropriate attributes that describe a new health service is imperative to ensure validity of the choice experiment. To identify important factors that are relevant to Malawian women's preferences for breast cancer detection services and to select attributes and levels for a discrete choice experiment in a setting where both breast cancer early detection and choice experiments are rare. We reviewed the literature to establish an initial list of potential attributes and levels for a discrete choice experiment and conducted qualitative interviews with health workers and community women to explore relevant local factors affecting decisions to use cancer detection services. We tested the design through cognitive interviews and refined the levels, descriptions, and designs. Themes that emerged from interviews provided critical information about breast cancer detection services, specifically, that breast cancer interventions should be integrated into other health services because asymptomatic screening may not be practical as an individual service. Based on participants' responses, the final attributes of the choice experiment included travel time, health encounter, health worker type and sex, and breast cancer early detection strategy. Cognitive testing confirmed the acceptability of the final attributes, comprehension of choice tasks, and women's abilities to make trade-offs. Applying a discrete choice experiment for breast cancer early detection was feasible with appropriate tailoring for a low-income, low-literacy African setting.

  17. Reconceptualising the external validity of discrete choice experiments.

    PubMed

    Lancsar, Emily; Swait, Joffre

    2014-10-01

    External validity is a crucial but under-researched topic when considering using discrete choice experiment (DCE) results to inform decision making in clinical, commercial or policy contexts. We present the theory and tests traditionally used to explore external validity that focus on a comparison of final outcomes and review how this traditional definition has been empirically tested in health economics and other sectors (such as transport, environment and marketing) in which DCE methods are applied. While an important component, we argue that the investigation of external validity should be much broader than a comparison of final outcomes. In doing so, we introduce a new and more comprehensive conceptualisation of external validity, closely linked to process validity, that moves us from the simple characterisation of a model as being or not being externally valid on the basis of predictive performance, to the concept that external validity should be an objective pursued from the initial conceptualisation and design of any DCE. We discuss how such a broader definition of external validity can be fruitfully used and suggest innovative ways in which it can be explored in practice.

  18. Discrete Choice Modeling (DCM): An Exciting Marketing Research Survey Method for Educational Researchers.

    ERIC Educational Resources Information Center

    Berdie, Doug R.

    Discrete Choice Marketing (DCM), a research technique that has become more popular in recent marketing research, is described. DCM is a method that forces people to look at the combination of relevant variables within each choice domain and, with each option fully defined in terms of the values for those variables, make a choice of options. DCM…

  19. Decision heuristic or preference? Attribute non-attendance in discrete choice problems.

    PubMed

    Heidenreich, Sebastian; Watson, Verity; Ryan, Mandy; Phimister, Euan

    2018-01-01

    This paper investigates if respondents' choice to not consider all characteristics of a multiattribute health service may represent preferences. Over the last decade, an increasing number of studies account for attribute non-attendance (ANA) when using discrete choice experiments to elicit individuals' preferences. Most studies assume such behaviour is a heuristic and therefore uninformative. This assumption may result in misleading welfare estimates if ANA reflects preferences. This is the first paper to assess if ANA is a heuristic or genuine preference without relying on respondents' self-stated motivation and the first study to explore this question within a health context. Based on findings from cognitive psychology, we expect that familiar respondents are less likely to use a decision heuristic to simplify choices than unfamiliar respondents. We employ a latent class model of discrete choice experiment data concerned with National Health Service managers' preferences for support services that assist with performance concerns. We present quantitative and qualitative evidence that in our study ANA mostly represents preferences. We also show that wrong assumptions about ANA result in inadequate welfare measures that can result in suboptimal policy advice. Future research should proceed with caution when assuming that ANA is a heuristic. Copyright © 2017 John Wiley & Sons, Ltd.

  20. Discrete choice experiment to evaluate factors that influence preferences for antibiotic prophylaxis in pediatric oncology.

    PubMed

    Regier, Dean A; Diorio, Caroline; Ethier, Marie-Chantal; Alli, Amanda; Alexander, Sarah; Boydell, Katherine M; Gassas, Adam; Taylor, Jonathan; Kellow, Charis; Mills, Denise; Sung, Lillian

    2012-01-01

    Bacterial and fungal infections in pediatric oncology patients cause morbidity and mortality. The clinical utility of antimicrobial prophylaxis in children is uncertain and the personal utility of these agents is disputed. Objectives were to use a discrete choice experiment to: (1) describe the importance of attributes to parents and healthcare providers when deciding between use and non-use of antibacterial and antifungal prophylaxis; and (2) estimate willingness-to-pay for prophylactic strategies. Attributes were chances of infection, death and side effects, route of administration and cost of pharmacotherapy. Respondents were randomized to a discrete choice experiment outlining hypothetical treatment options to prevent antibacterial or antifungal infections. Each respondent was presented 16 choice tasks and was asked to choose between two unlabeled treatment options and an opt-out alternative (no prophylaxis). 102 parents and 60 healthcare providers participated. For the antibacterial discrete choice experiment, frequency of administration was significantly associated with utility for parents but not for healthcare providers. Increasing chances of infection, death, side effects and cost were all significantly associated with decreased utility for parents and healthcare providers in both the antibacterial and antifungal discrete choice experiment. Parental willingness-to-pay was higher than healthcare providers for both strategies. Chances of infection, death, side effects and costs were all significantly associated with utility. Parents have higher willingness-to-pay for these strategies compared with healthcare providers. This knowledge can help to develop prophylaxis programs.

  1. Modeling the Bullying Prevention Program Preferences of Educators: A Discrete Choice Conjoint Experiment

    ERIC Educational Resources Information Center

    Cunningham, Charles E.; Vaillancourt, Tracy; Rimas, Heather; Deal, Ken; Cunningham, Lesley; Short, Kathy; Chen, Yvonne

    2009-01-01

    We used discrete choice conjoint analysis to model the bullying prevention program preferences of educators. Using themes from computerized decision support lab focus groups (n = 45 educators), we composed 20 three-level bullying prevention program design attributes. Each of 1,176 educators completed 25 choice tasks presenting experimentally…

  2. A labelled discrete choice experiment adds realism to the choices presented: preferences for surveillance tests for Barrett esophagus

    PubMed Central

    2009-01-01

    Background Discrete choice experiments (DCEs) allow systematic assessment of preferences by asking respondents to choose between scenarios. We conducted a labelled discrete choice experiment with realistic choices to investigate patients' trade-offs between the expected health gains and the burden of testing in surveillance of Barrett esophagus (BE). Methods Fifteen choice scenarios were selected based on 2 attributes: 1) type of test (endoscopy and two less burdensome fictitious tests), 2) frequency of surveillance. Each test-frequency combination was associated with its own realistic decrease in risk of dying from esophageal adenocarcinoma. A conditional logit model was fitted. Results Of 297 eligible patients (155 BE and 142 with non-specific upper GI symptoms), 247 completed the questionnaire (84%). Patients preferred surveillance to no surveillance. Current surveillance schemes of once every 1–2 years were amongst the most preferred alternatives. Higher health gains were preferred over those with lower health gains, except when test frequencies exceeded once a year. For similar health gains, patients preferred video-capsule over saliva swab and least preferred endoscopy. Conclusion This first example of a labelled DCE using realistic scenarios in a healthcare context shows that such experiments are feasible. A comparison of labelled and unlabelled designs taking into account setting and research question is recommended. PMID:19454022

  3. Using discrete choice experiments to understand preferences in health care.

    PubMed

    Pfarr, Christian; Schmid, Andreas; Schneider, Udo

    2014-01-01

    Whenever processes are reconfigured or new products are designed the needs and preferences of patients and consumers have to be considered. Although at times neglected, this becomes more and more relevant in health care settings: Which modes of health care delivery will be accepted? What are the patients' priorities and what is the willingness to pay? To which degree are patients mobile and for which kind of services are they willing to travel? Preferences, however, are difficult to measure, as they are latent constructs. This becomes even more difficult, when no past choices can be analyzed either as the service or the product is yet to be developed or as in the past there has not been free choice for patients. In such cases, preferences cannot be surveyed directly. Asking individuals openly for their attitudes towards certain services and products, the results are likely biased as individuals are not confronted with budget constraints and trade-offs. For this reason, discrete choice experiments (DCEs) are frequently used to elicit patient preferences. This approach confronts patients with hypothetical scenarios of which only one can be chosen. Over the past few years, this tool to reveal patients' preferences for health care has become very popular in health economics. This contribution aims at introducing the principles of DCEs, highlighting the underlying theory and giving practical guidance for conducting a discrete choice experiment in health economics. Thereby we focus on three major fields of patient demand: designing health insurance, assessing patient utility of new pharmaceuticals and analyzing provider choice. By having a closer look at selected international studies, we discuss the application of this technique for the analysis of the supply and the demand of health care as well as the implications for assessing patient mobility across different health care systems.

  4. ECONOMICS NOBEL: Dealing With Biases and Discrete Choices.

    PubMed

    Seife, C

    2000-10-20

    This year's Bank of Sweden Prize in Economic Sciences, given in honor of Alfred Nobel, goes to two researchers who gave the field of microeconomics--the study of individuals' economic behavior--new tools to help draw conclusions from imperfect data. James Heckman of the University of Chicago wins half of this year's prize for coming up with ways to deal with selection biases. Daniel McFadden of the University of California, Berkeley, tackled a different conundrum: how to quantify discrete choices rather than continuous ones.

  5. Discrete Choice Experiments: A Guide to Model Specification, Estimation and Software.

    PubMed

    Lancsar, Emily; Fiebig, Denzil G; Hole, Arne Risa

    2017-07-01

    We provide a user guide on the analysis of data (including best-worst and best-best data) generated from discrete-choice experiments (DCEs), comprising a theoretical review of the main choice models followed by practical advice on estimation and post-estimation. We also provide a review of standard software. In providing this guide, we endeavour to not only provide guidance on choice modelling but to do so in a way that provides a 'way in' for researchers to the practicalities of data analysis. We argue that choice of modelling approach depends on the research questions, study design and constraints in terms of quality/quantity of data and that decisions made in relation to analysis of choice data are often interdependent rather than sequential. Given the core theory and estimation of choice models is common across settings, we expect the theoretical and practical content of this paper to be useful to researchers not only within but also beyond health economics.

  6. Women's Preferences for Place of Delivery in Rural Tanzania: A Population-Based Discrete Choice Experiment

    PubMed Central

    Paczkowski, Magdalena; Mbaruku, Godfrey; de Pinho, Helen; Galea, Sandro

    2009-01-01

    Objectives. We fielded a population-based discrete choice experiment (DCE) in rural western Tanzania, where only one third of women deliver children in a health facility, to evaluate health-system factors that influence women's delivery decisions. Methods. Women were shown choice cards that described 2 hypothetical health centers by means of 6 attributes (distance, cost, type of provider, attitude of provider, drugs and equipment, free transport). The women were then asked to indicate which of the 2 facilities they would prefer to use for a future delivery. We used a hierarchical Bayes procedure to estimate individual and mean utility parameters. Results. A total of 1203 women completed the DCE. The model showed good predictive validity for actual facility choice. The most important facility attributes were a respectful provider attitude and availability of drugs and medical equipment. Policy simulations suggested that if these attributes were improved at existing facilities, the proportion of women preferring facility delivery would rise from 43% to 88%. Conclusions. In regions in which attended delivery rates are low despite availability of primary care facilities, policy experiments should test the effect of targeted quality improvements on facility use. PMID:19608959

  7. Breast Cancer Knowledge, Behaviors, and Preferences in Malawi: Implications for Early Detection Interventions From a Discrete Choice Experiment.

    PubMed

    Kohler, Racquel E; Gopal, Satish; Lee, Clara N; Weiner, Bryan J; Reeve, Bryce B; Wheeler, Stephanie B

    2017-10-01

    Breast cancer is the most common female cancer in Africa and leading cause of death resulting from cancer; however, many countries lack early detection services. In Malawi, women are frequently diagnosed with large tumors after long symptomatic periods. Little is known about local cancer knowledge. We administered a cross-sectional survey with a discrete choice experiment to a random sample in urban and rural areas of Lilongwe district. Bivariable and multivariable analyses determined factors associated with knowledge. Preference utilities for early detection interventions were estimated using a hierarchical Bayesian model in Sawtooth software. Of 213 women recruited, fewer than half were aware of breast cancer. In multivariable analysis, electricity at home and knowing someone with cancer increased the odds of awareness. Women were more knowledgeable about symptoms than treatment or risk factors; more than 60% erroneously believed local misconceptions. Seventeen percent were aware of breast self-examination, and 20% were aware of clinical breast examination (CBE); few reported either behavior. Common barriers included not knowing where to access CBE and transportation difficulties. Discrete choice experiment results indicated the detection strategy (breast health awareness, CBE, or both) was the most important attribute of an intervention, followed by the encounter setting and travel time. Addressing misconceptions in health messages and engaging survivors to promote early detection may help improve breast cancer knowledge in Malawi. Program designs accounting for women's preferences should provide breast health education and CBEs in convenient settings to address transportation barriers, particularly for women with low socioeconomic position.

  8. Breast Cancer Knowledge, Behaviors, and Preferences in Malawi: Implications for Early Detection Interventions From a Discrete Choice Experiment

    PubMed Central

    Gopal, Satish; Lee, Clara N.; Weiner, Bryan J.; Reeve, Bryce B.; Wheeler, Stephanie B.

    2017-01-01

    Purpose Breast cancer is the most common female cancer in Africa and leading cause of death resulting from cancer; however, many countries lack early detection services. In Malawi, women are frequently diagnosed with large tumors after long symptomatic periods. Little is known about local cancer knowledge. Methods We administered a cross-sectional survey with a discrete choice experiment to a random sample in urban and rural areas of Lilongwe district. Bivariable and multivariable analyses determined factors associated with knowledge. Preference utilities for early detection interventions were estimated using a hierarchical Bayesian model in Sawtooth software. Results Of 213 women recruited, fewer than half were aware of breast cancer. In multivariable analysis, electricity at home and knowing someone with cancer increased the odds of awareness. Women were more knowledgeable about symptoms than treatment or risk factors; more than 60% erroneously believed local misconceptions. Seventeen percent were aware of breast self-examination, and 20% were aware of clinical breast examination (CBE); few reported either behavior. Common barriers included not knowing where to access CBE and transportation difficulties. Discrete choice experiment results indicated the detection strategy (breast health awareness, CBE, or both) was the most important attribute of an intervention, followed by the encounter setting and travel time. Conclusion Addressing misconceptions in health messages and engaging survivors to promote early detection may help improve breast cancer knowledge in Malawi. Program designs accounting for women’s preferences should provide breast health education and CBEs in convenient settings to address transportation barriers, particularly for women with low socioeconomic position. PMID:29094086

  9. A multiple indicator solution approach to endogeneity in discrete-choice models for environmental valuation.

    PubMed

    Mariel, Petr; Hoyos, David; Artabe, Alaitz; Guevara, C Angelo

    2018-08-15

    Endogeneity is an often neglected issue in empirical applications of discrete choice modelling despite its severe consequences in terms of inconsistent parameter estimation and biased welfare measures. This article analyses the performance of the multiple indicator solution method to deal with endogeneity arising from omitted explanatory variables in discrete choice models for environmental valuation. We also propose and illustrate a factor analysis procedure for the selection of the indicators in practice. Additionally, the performance of this method is compared with the recently proposed hybrid choice modelling framework. In an empirical application we find that the multiple indicator solution method and the hybrid model approach provide similar results in terms of welfare estimates, although the multiple indicator solution method is more parsimonious and notably easier to implement. The empirical results open a path to explore the performance of this method when endogeneity is thought to have a different cause or under a different set of indicators. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. Patient preferences for osteoporosis in Spain: a discrete choice experiment.

    PubMed

    Darbà, J; Restovic, G; Kaskens, L; Balbona, M A; Carbonell, A; Cavero, P; Jordana, M; Prieto, C; Molina, A; Padró, I

    2011-06-01

    In Spain, various treatments are available to prevent osteoporotic fractures. A discrete choice experiment (DCE) was used to investigate the importance of different treatment aspects and its influence on patients' preferences. All attributes included as type and place of drug administration as well as costs showed to be significant predictors of choice. Spanish osteoporosis patients have well-defined preferences and accept trade-offs among attributes. This study was designed to identify patient preferences for different aspects of osteoporosis treatments in Spain. Main attributes of severe osteoporosis treatments were determined by literature review and consultations with nurses. The discrete choice experiment included three attributes: type of drug administration, place of administration, plus a cost attribute in order to estimate willingness to pay for improvements in attribute levels. A pilot study with 50 patients was performed to identify the areas of misunderstanding. One hundred sixty-six patients with a diagnosis of osteoporosis and severe osteoporosis were presented with pairs of hypothetical treatment profiles with different type of administration levels, places of administration and costs. Questions to collect socio-demographic and disease-related treatment data were also included. Data were analysed using a random effects probit model. All attributes had the expected polarity and were significant predictors of choice. Patients were willing to pay 183 euro/month to have a subcutaneous injection once per day rather than an intravenous injection once per year. Patients with osteoporosis were willing to pay 121 euro/month to have medical support when administering the drug treatment at home rather than being admitted several hours to a hospital for drug administration. Spanish osteoporosis patients have well-defined preferences among treatment attributes and are willing to accept trade-offs among attributes. Participants indicated that they are willing to

  11. Emerging Australian Education Markets: A Discrete Choice Model of Taiwanese and Indonesian Student Intended Study Destination.

    ERIC Educational Resources Information Center

    Kemp, Steven; Madden, Gary; Simpson, Michael

    1998-01-01

    Isolates factors influencing choice of Australia as a preferred destination for international students in emerging regional markets. Uses data obtained from a survey of students in Indonesia and Taiwan to estimate a U.S./Australia and rest-of-world/Australia discrete destination-choice model. This model identifies key factors determining country…

  12. Influence of injection mode on transport properties in kilometer-scale three-dimensional discrete fracture networks

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hyman, Jeffrey De'Haven; Painter, S. L.; Viswanathan, H.

    We investigate how the choice of injection mode impacts transport properties in kilometer-scale three-dimensional discrete fracture networks (DFN). The choice of injection mode, resident and flux-weighted, is designed to mimic different physical phenomena. It has been hypothesized that solute plumes injected under resident conditions evolve to behave similarly to solutes injected under flux-weighted conditions. Previously, computational limitations have prohibited the large-scale simulations required to investigate this hypothesis. We investigate this hypothesis by using a high-performance DFN suite, dfnWorks, to simulate flow in kilometer-scale three-dimensional DFNs based on fractured granite at the Forsmark site in Sweden, and adopt a Lagrangian approachmore » to simulate transport therein. Results show that after traveling through a pre-equilibrium region, both injection methods exhibit linear scaling of the first moment of travel time and power law scaling of the breakthrough curve with similar exponents, slightly larger than 2. Lastly, the physical mechanisms behind this evolution appear to be the combination of in-network channeling of mass into larger fractures, which offer reduced resistance to flow, and in-fracture channeling, which results from the topology of the DFN.« less

  13. Influence of injection mode on transport properties in kilometer-scale three-dimensional discrete fracture networks

    DOE PAGES

    Hyman, Jeffrey De'Haven; Painter, S. L.; Viswanathan, H.; ...

    2015-09-12

    We investigate how the choice of injection mode impacts transport properties in kilometer-scale three-dimensional discrete fracture networks (DFN). The choice of injection mode, resident and flux-weighted, is designed to mimic different physical phenomena. It has been hypothesized that solute plumes injected under resident conditions evolve to behave similarly to solutes injected under flux-weighted conditions. Previously, computational limitations have prohibited the large-scale simulations required to investigate this hypothesis. We investigate this hypothesis by using a high-performance DFN suite, dfnWorks, to simulate flow in kilometer-scale three-dimensional DFNs based on fractured granite at the Forsmark site in Sweden, and adopt a Lagrangian approachmore » to simulate transport therein. Results show that after traveling through a pre-equilibrium region, both injection methods exhibit linear scaling of the first moment of travel time and power law scaling of the breakthrough curve with similar exponents, slightly larger than 2. Lastly, the physical mechanisms behind this evolution appear to be the combination of in-network channeling of mass into larger fractures, which offer reduced resistance to flow, and in-fracture channeling, which results from the topology of the DFN.« less

  14. What influences participation in genetic carrier testing? Results from a discrete choice experiment.

    PubMed

    Hall, Jane; Fiebig, Denzil G; King, Madeleine T; Hossain, Ishrat; Louviere, Jordan J

    2006-05-01

    This study explores factors that influence participation in genetic testing programs and the acceptance of multiple tests. Tay Sachs and cystic fibrosis are both genetically determined recessive disorders with differing severity, treatment availability, and prevalence in different population groups. We used a discrete choice experiment with a general community and an Ashkenazi Jewish sample; data were analysed using multinomial logit with random coefficients. Although Jewish respondents were more likely to be tested, both groups seem to be making very similar tradeoffs across attributes when they make genetic testing choices.

  15. Patients' preferences for primary health care - a systematic literature review of discrete choice experiments.

    PubMed

    Kleij, Kim-Sarah; Tangermann, Ulla; Amelung, Volker E; Krauth, Christian

    2017-07-11

    Primary care is a key element of health care systems and addresses the main health problems of the population. Due to the demographic change, primary care even gains in importance. The knowledge of the patients' preferences can help policy makers as well as physicians to set priorities in their effort to make health care delivery more responsive to patients' needs. Our objective was to describe which aspects of primary care were included in preference studies and which of them were the most preferred aspects. In order to elicit the preferences for primary care, a systematic literature search was conducted. Two researchers searched three electronic databases (PubMed, Scopus, and PsycINFO) and conducted a narrative synthesis. Inclusion criteria were: focus on primary health care delivery, discrete choice experiment as elicitation method, and studies published between 2006 and 2015 in English language. We identified 18 studies that elicited either the patients' or the population's preferences for primary care based on a discrete choice experiment. Altogether the studies used 16 structure attributes, ten process attributes and four outcome attributes. The most commonly applied structure attribute was "Waiting time till appointment", the most frequently used process attribute was "Shared decision making / professional's attention paid to your views". "Receiving the 'best' treatment" was the most commonly applied outcome attribute. Process attributes were most often the ones of highest importance for patients or the population. The attributes and attribute levels used in the discrete choice experiments were identified by literature research, qualitative research, expert interviews, or the analysis of policy documents. The results of the DCE studies show different preferences for primary health care. The diversity of the results may have several reasons, such as the method of analysis, the selection procedure of the attributes and their levels or the specific research

  16. Patient Preferences for Pain Management in Advanced Cancer: Results from a Discrete Choice Experiment.

    PubMed

    Meads, David M; O'Dwyer, John L; Hulme, Claire T; Chintakayala, Phani; Vinall-Collier, Karen; Bennett, Michael I

    2017-10-01

    Pain from advanced cancer remains prevalent, severe and often under-treated. The aim of this study was to conduct a discrete choice experiment with patients to understand their preferences for pain management services and inform service development. Focus groups were used to develop the attributes and levels of the discrete choice experiment. The attributes were: waiting time, type of healthcare professional, out-of-pocket costs, side-effect control, quality of communication, quality of information and pain control. Patients completed the discrete choice experiment along with clinical and health-related quality of life questions. Conditional and mixed logit models were used to analyse the data. Patients with cancer pain (n = 221) and within palliative care services completed the survey (45% were female, mean age 64.6 years; age range 21-92 years). The most important aspects of pain management were: good pain control, zero out-of-pocket costs and good side-effect control. Poor or moderate pain control and £30 costs drew the highest negative preferences. Respondents preferred control of side effects and provision of better information and communication, over access to certain healthcare professionals. Those with lower health-related quality of life were less willing to wait for treatment and willing to incur higher costs. The presence of a carer influenced preferences. Outcome attributes were more important than process attributes but the latter were still valued. Thus, supporting self-management, for example by providing better information on pain may be a worthwhile endeavour. However, service provision may need to account for individual characteristics given the heterogeneity in preferences.

  17. Providing Information to Parents of Children with Mental Health Problems: A Discrete Choice Conjoint Analysis of Professional Preferences

    ERIC Educational Resources Information Center

    Cunningham, Charles E.; Deal, Ken; Rimas, Heather; Chen, Yvonne; Buchanan, Don H.; Sdao-Jarvie, Kathie

    2009-01-01

    We used discrete choice conjoint analysis to model the ways 645 children's mental health (CMH) professionals preferred to provide information to parents seeking CMH services. Participants completed 20 choice tasks presenting experimentally varied combinations of the study's 14 4-level CMH information transfer attributes. Latent class analysis…

  18. A Discrete Choice Conjoint Experiment to Evaluate Parent Preferences for Treatment of Young, Medication Naive Children with ADHD

    ERIC Educational Resources Information Center

    Waschbusch, Daniel A.; Cunningham, Charles E.; Pelham, William E., Jr.; Rimas, Heather L.; Greiner, Andrew R.; Gnagy, Elizabeth M.; Waxmonsky, James; Fabiano, Gregory A.; Robb, Jessica A.; Burrows-MacLean, Lisa; Scime, Mindy; Hoffman, Martin T.

    2011-01-01

    The current study examined treatment preferences of 183 parents of young (average age = 5.8 years, SD = 0.6), medication naive children with ADHD. Preferences were evaluated using a discrete choice experiment in which parents made choices between different combinations of treatment characteristics, outcomes, and costs. Latent class analysis…

  19. Hospital sector choice and support for public hospital care in New Zealand: Results from a labeled discrete choice survey.

    PubMed

    Brown, Paul; Panattoni, Laura; Cameron, Linda; Knox, Stephanie; Ashton, Toni; Tenbensel, Tim; Windsor, John

    2015-09-01

    This study uses a discrete choice experiment (DCE) to measure patients' preferences for public and private hospital care in New Zealand. A labeled DCE was administered to 583 members of the general public, with the choice between a public and private hospital for a non-urgent surgery. The results suggest that cost of surgery, waiting times for surgery, option to select a surgeon, convenience, and conditions of the hospital ward are important considerations for patients. The most important determinant of hospital choice was whether it was a public or private hospital, with respondents far more likely to choose a public hospital than a private hospital. The results have implications for government policy toward using private hospitals to clear waiting lists in public hospitals, with these results suggesting the public might not be indifferent to policies that treat private hospitals as substitutes for public hospitals. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Factors affecting food choices of older adults from high and low socioeconomic groups: a discrete choice experiment.

    PubMed

    Kamphuis, Carlijn B M; de Bekker-Grob, Esther W; van Lenthe, Frank J

    2015-04-01

    Healthiness, price, and convenience are typically indicated as important motives for food choices; however, it is largely unknown to what extent older adults from high and low socioeconomic groups differ in these underlying motives. A discrete choice experiment (DCE) is an innovative way to elicit implicit motives for food choices. The aim was to investigate differences in food motives between socioeconomic groups by means of a DCE. A DCE was carried out during a face-to-face interview among older adults as part of the Health and Living Conditions in Eindhoven and surrounding cities (GLOBE) cohort study, The Netherlands. Participants (n = 399; mean age: 63.3 y) were offered a series of choice sets about a usual dinner at home and were asked to choose in each choice set between 2 meals and an opt-out choice, with different combinations of attribute levels. We included 5 meal attributes (taste, healthiness, preparation time, travel time to shops, and price) and 3 or 4 levels for each attribute. Data were analyzed by multinomial logit models. Healthiness, taste, price, and travel time to the grocery store proved to significantly influence older adults' meal decisions; preparation time was not significant. Healthiness was the most important attribute for all of the participants. More highly educated participants rated a healthy and less expensive meal to be more important than did less educated participants. Those with a high income rated a meal that was healthy and very tasteful to be more important than did those with a lower income. Healthiness, taste, price, and travel time to grocery shops influenced older adults' meal decisions. Higher socioeconomic groups valued health more than did lower socioeconomic groups. DCEs represent a promising method to gain insight into the relative importance of motives for food choices. This trial was registered at www.isrctn.com as ISRCTN60293770. © 2015 American Society for Nutrition.

  1. Measuring the loss of consumer choice in mandatory health programmes using discrete choice experiments.

    PubMed

    Parkinson, Bonny; Goodall, Stephen; Norman, Richard

    2013-04-01

    Economic evaluation of mandatory health programmes generally do not consider the utility impact of a loss of consumer choice upon implementation, despite evidence suggesting that consumers do value having the ability to choose. The primary aim of this study was to explore whether the utility impact of a loss of consumer choice from implementing mandatory health programmes can be measured using discrete choice experiments (DCEs). Three case studies were used to test the methodology: fortification of bread-making flour with folate, mandatory influenza vaccination of children, and the banning of trans-fats. Attributes and levels were developed from a review of the literature. An orthogonal, fractional factorial design was used to select the profiles presented to respondents to allow estimation of main effects. Overall, each DCE consisted of 64 profiles which were allocated to four versions of 16 profiles. Each choice task compared two profiles, one being voluntary and the other being mandatory, plus a 'no policy' option, thus each respondent was presented with eight choice tasks. For each choice task, respondents were asked which health policy they most preferred and least preferred. Data was analysed using a mixed logit model with correlated coefficients (200 Halton draws). The compensating variation required for introducing a programme on a mandatory basis (versus achieving the same health impacts with a voluntary programme) that holds utility constant was estimated. Responses were provided by 535 participants (a response rate of 83 %). For the influenza vaccination and folate fortification programmes, the results suggested that some level of compensation may be required for introducing the programme on a mandatory basis. Introducing a mandatory influenza vaccination programme required the highest compensation (Australian dollars [A$] 112.75, 95 % CI -60.89 to 286.39) compared with folate fortification (A$18.05, 95 % CI -3.71 to 39.80). No compensation was

  2. Measuring stroke patients' exercise preferences using a discrete choice experiment.

    PubMed

    Geidl, Wolfgang; Knocke, Katja; Schupp, Wilfried; Pfeifer, Klaus

    2018-03-30

    Physical activity post stroke improves health, yet physical inactivity is highly prevalent. Tailored exercise programs considering physical activity preferences are a promising approach to promote physical activity. Therefore, this study seeks to measure exercise preferences of stroke survivors. Stroke survivors conducted a discrete choice experiment (DCE). DCE was presented in a face-to-face interview where patients had to choose eight times between two different exercise programs. Exercise programs differed by characteristics, with the six attributes under consideration being social situation, location, type of exercise, intensity, frequency, and duration. Utilities of the exercise attributes were estimated with a logit choice model. Stroke survivors (n=103, mean age: 67, SD=13.0; 60% male) show significant differences in the rated utilities of the exercise attributes (P<0.001). Participants had strong preferences for light and moderate intense physical activity and favored shorter exercise sessions. Stroke survivors have remarkable exercise preferences especially for intensity and duration of exercise. Results contribute to the tailoring of physical activity programs after stroke thereby facilitating maintenance of physical activity.

  3. Transport and discrete particle noise in gyrokinetic simulations

    NASA Astrophysics Data System (ADS)

    Jenkins, Thomas; Lee, W. W.

    2006-10-01

    We present results from our recent investigations regarding the effects of discrete particle noise on the long-time behavior and transport properties of gyrokinetic particle-in-cell simulations. It is found that the amplitude of nonlinearly saturated drift waves is unaffected by discreteness-induced noise in plasmas whose behavior is dominated by a single mode in the saturated state. We further show that the scaling of this noise amplitude with particle count is correctly predicted by the fluctuation-dissipation theorem, even though the drift waves have driven the plasma from thermal equilibrium. As well, we find that the long-term behavior of the saturated system is unaffected by discreteness-induced noise even when multiple modes are included. Additional work utilizing a code with both total-f and δf capabilities is also presented, as part of our efforts to better understand the long- time balance between entropy production, collisional dissipation, and particle/heat flux in gyrokinetic plasmas.

  4. Estimation of Dynamic Discrete Choice Models by Maximum Likelihood and the Simulated Method of Moments

    PubMed Central

    Eisenhauer, Philipp; Heckman, James J.; Mosso, Stefano

    2015-01-01

    We compare the performance of maximum likelihood (ML) and simulated method of moments (SMM) estimation for dynamic discrete choice models. We construct and estimate a simplified dynamic structural model of education that captures some basic features of educational choices in the United States in the 1980s and early 1990s. We use estimates from our model to simulate a synthetic dataset and assess the ability of ML and SMM to recover the model parameters on this sample. We investigate the performance of alternative tuning parameters for SMM. PMID:26494926

  5. Modelling discrete choice variables in assessment of teaching staff work satisfaction.

    PubMed

    Mieilă, Mihai; Popescu, Constanţa; Tudorache, Ana-Maria; Toplicianu, Valerică

    2015-01-01

    Levels of self-reported job satisfaction and motivation were measured by survey in a sample of 286 teachers. Using the discrete choice framework, the paper tries to assess the relevance of the considered indicators (demographic, social, motivational) in overall teaching work satisfaction. The findings provide evidence that job satisfaction is correlated significantly with level of university degree held by the teacher, type of secondary school where the teacher is enrolled, revenues, and salary-tasks adequacy. This is important for the Romanian economy, since the education system is expected to provide future human resources with enhanced skills and abilities.

  6. Modelling Discrete Choice Variables in Assessment of Teaching Staff Work Satisfaction

    PubMed Central

    2015-01-01

    Levels of self-reported job satisfaction and motivation were measured by survey in a sample of 286 teachers. Using the discrete choice framework, the paper tries to assess the relevance of the considered indicators (demographic, social, motivational) in overall teaching work satisfaction. The findings provide evidence that job satisfaction is correlated significantly with level of university degree held by the teacher, type of secondary school where the teacher is enrolled, revenues, and salary-tasks adequacy. This is important for the Romanian economy, since the education system is expected to provide future human resources with enhanced skills and abilities. PMID:25849295

  7. Eliciting preferences for medical devices in South Korea: A discrete choice experiment.

    PubMed

    Lee, Hye-Jae; Bae, Eun-Young

    2017-03-01

    This study aims to identify the attributes that contribute to the value of medical devices and quantify the relative importance of them using a discrete choice experiment. Based on a literature review and expert consultation, seven attributes and their levels were identified-severity of disease (2), availability of substitutes (2), improvement in procedure (3), improvement in clinical outcomes (2), increase in survival (2), improvement in quality of life (3), and cost (4). Among 576 hypothetical profiles, optimal choice sets with 20 choices were developed and experts experienced in health technology assessment and reimbursement decision making in South Korea were surveyed. A total of 102 respondents participated in the survey. The results of the random-effect probit model showed that among the seven attributes, six, except for improvement in procedure, had a significant impact on respondents' choices on medical devices. Respondents were willing to pay the highest amount for devices that provided substantial improvements in quality of life, followed by increased survival, improved clinical outcome, treatment without substitutes, and technology for treating severe diseases. The findings of this experiment will inform decision-makers of the relative importance of the criteria and help them in reimbursement decision making of medical devices. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Testing Ecological Theories of Offender Spatial Decision Making Using a Discrete Choice Model

    PubMed Central

    Summers, Lucia

    2015-01-01

    Research demonstrates that crime is spatially concentrated. However, most research relies on information about where crimes occur, without reference to where offenders reside. This study examines how the characteristics of neighborhoods and their proximity to offender home locations affect offender spatial decision making. Using a discrete choice model and data for detected incidents of theft from vehicles (TFV), we test predictions from two theoretical perspectives—crime pattern and social disorganization theories. We demonstrate that offenders favor areas that are low in social cohesion and closer to their home, or other age-related activity nodes. For adult offenders, choices also appear to be influenced by how accessible a neighborhood is via the street network. The implications for criminological theory and crime prevention are discussed. PMID:25866412

  9. Testing Ecological Theories of Offender Spatial Decision Making Using a Discrete Choice Model.

    PubMed

    Johnson, Shane D; Summers, Lucia

    2015-04-01

    Research demonstrates that crime is spatially concentrated. However, most research relies on information about where crimes occur, without reference to where offenders reside. This study examines how the characteristics of neighborhoods and their proximity to offender home locations affect offender spatial decision making. Using a discrete choice model and data for detected incidents of theft from vehicles (TFV) , we test predictions from two theoretical perspectives-crime pattern and social disorganization theories. We demonstrate that offenders favor areas that are low in social cohesion and closer to their home, or other age-related activity nodes. For adult offenders, choices also appear to be influenced by how accessible a neighborhood is via the street network. The implications for criminological theory and crime prevention are discussed.

  10. Discrete Diffusion Monte Carlo for Electron Thermal Transport

    NASA Astrophysics Data System (ADS)

    Chenhall, Jeffrey; Cao, Duc; Wollaeger, Ryan; Moses, Gregory

    2014-10-01

    The iSNB (implicit Schurtz Nicolai Busquet electron thermal transport method of Cao et al. is adapted to a Discrete Diffusion Monte Carlo (DDMC) solution method for eventual inclusion in a hybrid IMC-DDMC (Implicit Monte Carlo) method. The hybrid method will combine the efficiency of a diffusion method in short mean free path regions with the accuracy of a transport method in long mean free path regions. The Monte Carlo nature of the approach allows the algorithm to be massively parallelized. Work to date on the iSNB-DDMC method will be presented. This work was supported by Sandia National Laboratory - Albuquerque.

  11. Valuing SF-6D Health States Using a Discrete Choice Experiment.

    PubMed

    Norman, Richard; Viney, Rosalie; Brazier, John; Burgess, Leonie; Cronin, Paula; King, Madeleine; Ratcliffe, Julie; Street, Deborah

    2014-08-01

    SF-6D utility weights are conventionally produced using a standard gamble (SG). SG-derived weights consistently demonstrate a floor effect not observed with other elicitation techniques. Recent advances in discrete choice methods have allowed estimation of utility weights. The objective was to produce Australian utility weights for the SF-6D and to explore the application of discrete choice experiment (DCE) methods in this context. We hypothesized that weights derived using this method would reflect the largely monotonic construction of the SF-6D. We designed an online DCE and administered it to an Australia-representative online panel (n = 1017). A range of specifications investigating nonlinear preferences with respect to additional life expectancy were estimated using a random-effects probit model. The preferred model was then used to estimate a preference index such that full health and death were valued at 1 and 0, respectively, to provide an algorithm for Australian cost-utility analyses. Physical functioning, pain, mental health, and vitality were the largest drivers of utility weights. Combining levels to remove illogical orderings did not lead to a poorer model fit. Relative to international SG-derived weights, the range of utility weights was larger with 5% of health states valued below zero. s. DCEs can be used to investigate preferences for health profiles and to estimate utility weights for multi-attribute utility instruments. Australian cost-utility analyses can now use domestic SF-6D weights. The comparability of DCE results to those using other elicitation methods for estimating utility weights for quality-adjusted life-year calculations should be further investigated. © The Author(s) 2013.

  12. Age and choice in health insurance: evidence from a discrete choice experiment.

    PubMed

    Becker, Karolin; Zweifel, Peter

    2008-01-01

    A uniform package of benefits and uniform cost sharing are elements of regulation inherent in most social health insurance systems. Both elements risk burdening the population with a welfare loss if preferences for risk and insurance attributes differ. This suggests the introduction of more choice in social health insurance packages may be advantageous; however, it is widely believed that this would not benefit the elderly.A representative telephone survey of 1000 people aged >24 years living in the German- and French-speaking parts of Switzerland was conducted. Participants were asked to compare the status quo (i.e. their current insurance contract) with ten hypothetical alternatives. In addition, participants were asked questions concerning utilization of healthcare services; overall satisfaction with the healthcare system, insurer and insurance policy; and a general preference for new elements in the insurance package. Socioeconomic variables surveyed were age, sex, total household income, education (seven categories ranging from primary school to university degree), place of residence, occupation, and marital status. To examine the relationship between age and willingness to pay (WTP) for additional options in Swiss social health insurance.A representative telephone survey of 1000 people aged >24 years living in the German- and French-speaking parts of Switzerland was conducted. Participants were asked to compare the status quo (i.e. their current insurance contract) with ten hypothetical alternatives. In addition, participants were asked questions concerning utilization of healthcare services; overall satisfaction with the healthcare system, insurer and insurance policy; and a general preference for new elements in the insurance package. Socioeconomic variables surveyed were age, sex, total household income, education (seven categories ranging from primary school to university degree), place of residence, occupation, and marital status. A discrete choice

  13. Multiple Choice Knapsack Problem: example of planning choice in transportation.

    PubMed

    Zhong, Tao; Young, Rhonda

    2010-05-01

    Transportation programming, a process of selecting projects for funding given budget and other constraints, is becoming more complex as a result of new federal laws, local planning regulations, and increased public involvement. This article describes the use of an integer programming tool, Multiple Choice Knapsack Problem (MCKP), to provide optimal solutions to transportation programming problems in cases where alternative versions of projects are under consideration. In this paper, optimization methods for use in the transportation programming process are compared and then the process of building and solving the optimization problems is discussed. The concepts about the use of MCKP are presented and a real-world transportation programming example at various budget levels is provided. This article illustrates how the use of MCKP addresses the modern complexities and provides timely solutions in transportation programming practice. While the article uses transportation programming as a case study, MCKP can be useful in other fields where a similar decision among a subset of the alternatives is required. Copyright 2009 Elsevier Ltd. All rights reserved.

  14. Modelling the Preferences of Students for Alternative Assignment Designs Using the Discrete Choice Experiment Methodology

    ERIC Educational Resources Information Center

    Kennelly, Brendan; Flannery, Darragh; Considine, John; Doherty, Edel; Hynes, Stephen

    2014-01-01

    This paper outlines how a discrete choice experiment (DCE) can be used to learn more about how students are willing to trade off various features of assignments such as the nature and timing of feedback and the method used to submit assignments. A DCE identifies plausible levels of the key attributes of a good or service and then presents the…

  15. Dialysis modality preference of patients with CKD and family caregivers: a discrete-choice study.

    PubMed

    Morton, Rachael L; Snelling, Paul; Webster, Angela C; Rose, John; Masterson, Rosemary; Johnson, David W; Howard, Kirsten

    2012-07-01

    Dialysis modality preferences of patients with chronic kidney disease (CKD) and family caregivers are important, yet rarely quantified. Prospective, unlabeled, discrete-choice experiment with random-parameter logit analysis. Adults with stages 3-5 CKD and caregivers educated about dialysis treatment options from 8 Australian renal clinics. Preferences for and trade-offs between the dialysis treatment attributes of life expectancy, number of hospital visits per week, ability to travel, hours per treatment, treatment time of day, subsidized transport service, and flexibility of treatment schedule. Results presented as ORs for preferring home-based or in-center dialysis to conservative care. 105 predialysis patients and 73 family caregivers completed the study. Median patient age was 63 years, and mean estimated glomerular filtration rate was 18.1 (range, 6-34) mL/min/1.73 m(2). Median caregiver age was 61 years. Home-based dialysis (either peritoneal or home hemodialysis) was chosen by patients in 65% of choice sets; in-center dialysis, in 35%; and conservative care, in 10%. For caregivers, this was 72%, 25%, and 3%, respectively. Both patients and caregivers preferred longer rather than shorter hours of dialysis (ORs of 2.02 [95% CI, 1.51-2.70] and 2.67 [95% CI, 1.85-3.85] for patients and caregivers, respectively), but were less likely to choose nocturnal than daytime dialysis (ORs of 0.07 [95% CI, 0.01-0.75] and 0.03 [95% CI, 0.01-0.20]). Patients were willing to forgo 23 (95% CI, 19-27) months of life expectancy with home-based dialysis to decrease their travel restrictions. For caregivers, this was 17 (95% CI, 16-18) patient-months. Data were limited to stated preferences rather than actual choice of dialysis modality. Our study suggests that it is rare for caregivers to prefer conservative nondialytic care for family members with CKD. Home-based dialysis modalities that enable patients and their family members to travel with minimal restriction would be

  16. Application of rrm as behavior mode choice on modelling transportation

    NASA Astrophysics Data System (ADS)

    Surbakti, M. S.; Sadullah, A. F.

    2018-03-01

    Transportation mode selection, the first step in transportation planning process, is probably one of the most important planning elements. The development of models that can explain the preference of passengers regarding their chosen mode of public transport option will contribute to the improvement and development of existing public transport. Logit models have been widely used to determine the mode choice models in which the alternative are different transport modes. Random Regret Minimization (RRM) theory is a theory developed from the behavior to choose (choice behavior) in a state of uncertainty. During its development, the theory was used in various disciplines, such as marketing, micro economy, psychology, management, and transportation. This article aims to show the use of RRM in various modes of selection, from the results of various studies that have been conducted both in north sumatera and western Java.

  17. The theory of planned behaviour and discrete food choices: a systematic review and meta-analysis.

    PubMed

    McDermott, Máirtín S; Oliver, Madalyn; Svenson, Alexander; Simnadis, Thomas; Beck, Eleanor J; Coltman, Tim; Iverson, Don; Caputi, Peter; Sharma, Rajeev

    2015-12-30

    The combination of economic and social costs associated with non-communicable diseases provide a compelling argument for developing strategies that can influence modifiable risk factors, such as discrete food choices. Models of behaviour, such as the Theory of Planned Behaviour (TPB) provide conceptual order that allows program designers and policy makers to identify the substantive elements that drive behaviour and design effective interventions. The primary aim of the current review was to examine the association between TPB variables and discrete food choice behaviours. A systematic literature search was conducted to identify relevant studies. Calculation of the pooled mean effect size (r(+)) was conducted using inverse-variance weighted, random effects meta-analysis. Heterogeneity across studies was assessed using the Q- and I(2)-statistics. Meta-regression was used to test the impact of moderator variables: type of food choice behaviour; participants' age and gender. A total of 42 journal articles and four unpublished dissertations met the inclusion criteria. TPB variables were found to have medium to large associations with both intention and behaviour. Attitudes had the strongest association with intention (r(+)  = 0.54) followed by perceived behavioural control (PBC, r(+)  = 0.42) and subjective norm (SN, r(+)  = 0.37). The association between intention and behaviour was r(+)  = 0.45 and between PBC and behaviour was r(+)  = 0.27. Moderator analyses revealed the complex nature of dietary behaviour and the factors that underpin individual food choices. Significantly higher PBC-behaviour associations were found for choosing health compromising compared to health promoting foods. Significantly higher intention-behaviour and PBC-behaviour associations were found for choosing health promoting foods compared to avoiding health compromising foods. Participant characteristics were also found to moderate associations within the model. Higher

  18. Specification of the utility function in discrete choice experiments.

    PubMed

    van der Pol, Marjon; Currie, Gillian; Kromm, Seija; Ryan, Mandy

    2014-03-01

    The specification of the utility function has received limited attention within the discrete choice experiment (DCE) literature. This lack of investigation is surprising given that evidence from the contingent valuation literature suggests that welfare estimates are sensitive to different specifications of the utility function. This study investigates the effect of different specifications of the utility function on results within a DCE. The DCE elicited the public's preferences for waiting time for hip and knee replacement and estimated willingness to wait (WTW). The results showed that the WTW for the different patient profiles varied considerably across the three different specifications of the utility function. Assuming a linear utility function led to much higher estimates of marginal rates of substitution (WTWs) than with nonlinear specifications. The goodness-of-fit measures indicated that nonlinear specifications were superior. Copyright © 2014 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  19. Prediction of discretization error using the error transport equation

    NASA Astrophysics Data System (ADS)

    Celik, Ismail B.; Parsons, Don Roscoe

    2017-06-01

    This study focuses on an approach to quantify the discretization error associated with numerical solutions of partial differential equations by solving an error transport equation (ETE). The goal is to develop a method that can be used to adequately predict the discretization error using the numerical solution on only one grid/mesh. The primary problem associated with solving the ETE is the formulation of the error source term which is required for accurately predicting the transport of the error. In this study, a novel approach is considered which involves fitting the numerical solution with a series of locally smooth curves and then blending them together with a weighted spline approach. The result is a continuously differentiable analytic expression that can be used to determine the error source term. Once the source term has been developed, the ETE can easily be solved using the same solver that is used to obtain the original numerical solution. The new methodology is applied to the two-dimensional Navier-Stokes equations in the laminar flow regime. A simple unsteady flow case is also considered. The discretization error predictions based on the methodology presented in this study are in good agreement with the 'true error'. While in most cases the error predictions are not quite as accurate as those from Richardson extrapolation, the results are reasonable and only require one numerical grid. The current results indicate that there is much promise going forward with the newly developed error source term evaluation technique and the ETE.

  20. Consumer preferences for electronic cigarettes: results from a discrete choice experiment.

    PubMed

    Czoli, Christine D; Goniewicz, Maciej; Islam, Towhidul; Kotnowski, Kathy; Hammond, David

    2016-04-01

    E-cigarettes present a formidable challenge to regulators given their variety and the rapidly evolving nicotine market. The current study sought to examine the influence of e-cigarette product characteristics on consumer perceptions and trial intentions among Canadians. An online discrete choice experiment was conducted with 915 Canadians aged 16 years and older in November 2013. An online commercial panel was used to sample 3 distinct subpopulations: (1) non-smoking youth and young adults (n=279); (2) smoking youth and young adults (n=264) and (3) smoking adults (n=372). Participants completed a series of stated-preference tasks, in which they viewed choice sets with e-cigarette product images that featured different combinations of attributes: flavour, nicotine content, health warnings and price. For each choice set, participants were asked to select one of the products or indicate 'none of the above' with respect to the following outcomes: interest in trying, less harm and usefulness in quitting smoking. The attributes' impact on consumer choice for each outcome was analysed using multinomial logit regression. Health warning was the most important attribute influencing participants' intentions to try e-cigarettes (42%) and perceived efficacy as a quit aid (39%). Both flavour (36%) and health warnings (35%) significantly predicted perceptions of product harm. The findings indicate that consumers make trade-offs with respect to e-cigarette product characteristics, and that these trade-offs vary across different subpopulations. Given that health warnings and flavour were weighted most important by consumers in this study, these may represent good targets for e-cigarette regulatory frameworks. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  1. Supporting driver headway choice: the effects of discrete headway feedback when following headway instructions.

    PubMed

    Risto, Malte; Martens, Marieke H

    2014-07-01

    With specific headway instructions drivers are not able to attain the exact headways as instructed. In this study, the effects of discrete headway feedback (and the direction of headway adjustment) on headway accuracy for drivers carrying out time headway instructions were assessed experimentally. Two groups of each 10 participants (one receiving headway feedback; one control) carried out headway instructions in a driving simulator; increasing and decreasing their headway to a target headway of 2 s at speeds of 50, 80, and 100 km/h. The difference between the instructed and chosen headway was a measure for headway accuracy. The feedback group heard a sound signal at the moment that they crossed the distance of the instructed headway. Unsupported participants showed no significant difference in headway accuracy when increasing or decreasing headways. Discrete headway feedback had varying effects on headway choice accuracy. When participants decreased their headway, feedback led to higher accuracy. When increasing their headway, feedback led to a lower accuracy, compared to no headway feedback. Support did not affect driver's performance in maintaining the chosen headway. The present results suggest that (a) in its current form discrete headway feedback is not sufficient to improve the overall accuracy of chosen headways when carrying out headway instructions; (b) the effect of discrete headway feedback depends on the direction of headway adjustment. Copyright © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  2. Societal preferences for rheumatoid arthritis treatments: evidence from a discrete choice experiment.

    PubMed

    Harrison, Mark; Marra, Carlo; Shojania, Kam; Bansback, Nick

    2015-10-01

    There is a concern that cost-effectiveness analysis using quality-adjusted life years does not capture all valuable benefits of treatments. The objective of this study was to determine the value society places on aspects of RA treatment to inform policymaking. A discrete choice experiment was administered to a representative sample of the Canadian general population. The discrete choice experiment, developed using focus groups, had seven attributes (route and frequency of administration, chance of benefit, chance of serious and minor side effects, confidence in evidence and life expectancy). A conditional logit regression model was used to estimate the significance and relative importance of attributes in influencing preferences on the quality-adjusted life years scale. Responses from 733 respondents who provided rational responses were analysed. Six attribute levels within four attributes significantly influenced preferences for treatments: a willingness to trade a year of life expectancy over a 10-year period to increase the probability of benefiting from treatment, or two-thirds of a year to reduce minor or serious side effects to the lowest level or improve the confidence in benefit/side-effect estimates. There was also some evidence of a preference for oral drug delivery, though a subgroup analysis suggested this preference was restricted to injection-naive respondents. Our results suggest society values the degree of confidence in the estimates of risks and benefits of RA treatments and the route of administration, as well as benefits and side effects. This study provides important evidence to policymakers determining the cost-effectiveness of treatments in arthritis. © The Author 2015. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. Designing a Transportation System for a Parent Choice School District: A Transportation Supervisor's Handbook.

    ERIC Educational Resources Information Center

    Paller, Alan; And Others

    This study was commissioned to investigate the special transportation problems in parent-choice school districts and to prepare a handbook to assist transportation supervisors in overcoming these problems. Intended for school districts that have alternative schools, open enrollment plans, magnet schools, or other kinds of parent and student choice…

  4. Personal health records in the Netherlands: potential user preferences quantified by a discrete choice experiment.

    PubMed

    Determann, Domino; Lambooij, Mattijs S; Gyrd-Hansen, Dorte; de Bekker-Grob, Esther W; Steyerberg, Ewout W; Heldoorn, Marcel; Pedersen, Line Bjørnskov; de Wit, G Ardine

    2017-05-01

    To identify groups of potential users based on their preferences for characteristics of personal health records (PHRs) and to estimate potential PHR uptake. We performed a discrete choice experiment, which consisted of 12 choice scenarios, each comprising 2 hypothetical PHR alternatives and an opt-out. The alternatives differed based on 5 characteristics. The survey was administered to Internet panel members of the Dutch Federation of Patients and Consumer Organizations. We used latent class models to analyze the data. A total of 1,443 potential PHR users completed the discrete choice experiment. We identified 3 latent classes: "refusers" (class probability 43%), "eager adopters" (37%), and "reluctant adopters" (20%). The predicted uptake for the reluctant adopters ranged from 4% in the case of a PHR with the worst attribute levels to 68% in the best case. Those with 1 or more chronic diseases were significantly more likely to belong to the eager adopter class. The data storage provider was the most decisive aspect for the eager and reluctant adopters, while cost was most decisive for the refusers. Across all classes, health care providers and independent organizations were the most preferred data storage providers. We identified 3 groups, of which 1 group (more than one-third of potential PHR users) indicated great interest in a PHR irrespective of PHR characteristics. Policymakers who aim to expand the use of PHRs will be most successful when health care providers and health facilities or independent organizations store PHR data while refraining from including market parties. © The Author 2016. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  5. A framework for estimating health state utility values within a discrete choice experiment: modeling risky choices.

    PubMed

    Robinson, Angela; Spencer, Anne; Moffatt, Peter

    2015-04-01

    There has been recent interest in using the discrete choice experiment (DCE) method to derive health state utilities for use in quality-adjusted life year (QALY) calculations, but challenges remain. We set out to develop a risk-based DCE approach to derive utility values for health states that allowed 1) utility values to be anchored directly to normal health and death and 2) worse than dead health states to be assessed in the same manner as better than dead states. Furthermore, we set out to estimate alternative models of risky choice within a DCE model. A survey was designed that incorporated a risk-based DCE and a "modified" standard gamble (SG). Health state utility values were elicited for 3 EQ-5D health states assuming "standard" expected utility (EU) preferences. The DCE model was then generalized to allow for rank-dependent expected utility (RDU) preferences, thereby allowing for probability weighting. A convenience sample of 60 students was recruited and data collected in small groups. Under the assumption of "standard" EU preferences, the utility values derived within the DCE corresponded fairly closely to the mean results from the modified SG. Under the assumption of RDU preferences, the utility values estimated are somewhat lower than under the assumption of standard EU, suggesting that the latter may be biased upward. Applying the correct model of risky choice is important whether a modified SG or a risk-based DCE is deployed. It is, however, possible to estimate a probability weighting function within a DCE and estimate "unbiased" utility values directly, which is not possible within a modified SG. We conclude by setting out the relative strengths and weaknesses of the 2 approaches in this context. © The Author(s) 2014.

  6. Using Blocked Fractional Factorial Designs to Construct Discrete Choice Experiments for Health Care Studies

    PubMed Central

    Jaynes, Jessica; Wong, Weng Kee; Xu, Hongquan

    2016-01-01

    Discrete choice experiments (DCEs) are increasingly used for studying and quantifying subjects preferences in a wide variety of health care applications. They provide a rich source of data to assess real-life decision making processes, which involve trade-offs between desirable characteristics pertaining to health and health care, and identification of key attributes affecting health care. The choice of the design for a DCE is critical because it determines which attributes’ effects and their interactions are identifiable. We apply blocked fractional factorial designs to construct DCEs and address some identification issues by utilizing the known structure of blocked fractional factorial designs. Our design techniques can be applied to several situations including DCEs where attributes have different number of levels. We demonstrate our design methodology using two health care studies to evaluate (1) asthma patients’ preferences for symptom-based outcome measures, and (2) patient preference for breast screening services. PMID:26823156

  7. Do patients prefer mesh or anterior colporrhaphy for primary correction of anterior vaginal wall prolapse: a labelled discrete choice experiment.

    PubMed

    Notten, K J B; Essers, B A; Weemhoff, M; Rutten, A G H; Donners, J J A E; van Gestel, I; Kruitwagen, R F P M; Roovers, J P W R; Dirksen, C D

    2015-05-01

    We investigated patients' preferences for anterior colporrhaphy or mesh surgery as surgical correction of anterior vaginal wall prolapse. Labelled discrete choice experiment. Three Dutch teaching hospitals. Women with anterior vaginal wall prolapse Pelvic Organ Prolapse Quantification stage 2 or more, indicated for anterior colporrhaphy (n = 100). Discrete choice experiments are an attribute-based survey method for measuring preferences. In this experiment, women were asked to choose between two treatment scenarios, mesh surgery or anterior colporrhaphy. These surgical treatments differed in four treatment attributes: (i) recurrence rate, (ii) exposure rate, (iii) infection rate, (iv) dyspareunia. Data were analysed using a multinomial logit model. Women's preferences for anterior colporrhaphy or mesh surgery for the repair of vaginal wall prolapse. All treatment attributes, i.e. recurrence, exposure, infection and dyspareunia, proved to be significant in the woman's decision to choose mesh surgery (P < 0.001), while only two attributes out of three, recurrence and infection, were significant for anterior colporrhaphy (P < 0.001). The relative importance data showed that with regards to the four statistically significant attributes for mesh, dyspareunia was the most important attribute, and of the two significant attributes for anterior colporrhaphy, the risk of infection. Based on the attributes and levels in our discrete choice experiment, anterior colporrhaphy was preferred in 74% as a primary correction of anterior vaginal wall prolapse, followed by a preference for mesh in 26% of all choices. This study showed that next to the risk of recurrence, other aspects like risk of infection, dyspareunia and exposure play a role in the woman's preference for a surgical treatment. In addition, our results indicate that anterior colporrhaphy is preferred in the majority of the choices, followed by a preference for mesh surgery in a quarter of all choice sets. However

  8. A discrete choice experiment to determine UK patient preference for attributes of disease modifying treatments in Multiple Sclerosis.

    PubMed

    Bottomley, Catherine; Lloyd, Andrew; Bennett, Gary; Adlard, Nicholas

    2017-08-01

    The recent licensing of Disease Modifying Treatments (DMTs) for Multiple Sclerosis (MS) has increased available treatment options. The aim of this study was to explore MS patients' preference for the different attributes of DMTs in the UK. Attributes (treatment characteristics) for inclusion in the discrete choice experiment (DCE) were determined through published literature and interviews with 12 people with MS. Seven attributes were selected. Participants were presented with three hypothetical treatment options sampled from included attributes and asked for their most/least preferred options. The influence of patient characteristics and demographics on patient preference was also investigated. The DCE was completed by 350 people with MS (81% female, mean age = 39). Results showed that method of taking medication was the strongest determinant of preference (27%; relative importance out of 100%), followed by relapse free rate (21%) and symptom progression (14%). Risk of fatigue (8%) and type of monitoring (6%) were the weakest determinants of preference. Once-daily oral treatment was preferred over all other methods of administration. Participant characteristics did not influence data on strength of preference. This study assumed adequate participant understanding of the discrete choice experiment task, and recruitment targeted those with access to the internet. These results, derived from people with MS in the UK, should be used to inform individual discussions with patients about DMT choices.

  9. Determinants of the choice of GP practice registration in England: evidence from a discrete choice experiment.

    PubMed

    Lagarde, Mylene; Erens, Bob; Mays, Nicholas

    2015-04-01

    There have been growing concerns that general practitioner (GP) services in England, which are based on registration with a single practice located near the patient's home, are not sufficiently convenient for patients. To inform the decision as to whether to change registration rules allowing patients to register 'out-of-area' and to estimate the demand for this wider choice, we undertook a discrete choice experiment with 1706 respondents. Latent class models were used to analyse preferences for GP practice registration comparing preferences for neighbourhood and non-neighbourhood practices. We find that there is some appetite for registering outside the neighbourhood, but this preference is not uniformly shared across the population. Specifically individuals who are less mobile (e.g. older people and those with caring responsibilities), or satisfied with their local practice are less likely to be interested in registering at a practice outside their neighbourhood. Overall, people feel most strongly about obtaining an appointment with a GP as quickly as possible. Respondents regarded weekend opening as less important than other factors, and particularly less important than extended practice opening hours from Monday to Friday. Assuming a constant demand for GP services, a policy encouraging GP practices to extend their opening hours during the week is likely to decrease the average patient waiting time for an appointment and is likely to be preferred by patients. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  10. Developing attributes and attribute-levels for a discrete choice experiment on micro health insurance in rural Malawi

    PubMed Central

    2014-01-01

    Background Discrete choice experiments (DCEs) are attribute-driven experimental techniques used to elicit stakeholders’ preferences to support the design and implementation of policy interventions. The validity of a DCE, therefore, depends on the appropriate specification of the attributes and their levels. There have been recent calls for greater rigor in implementing and reporting on the processes of developing attributes and attribute-levels for discrete choice experiments (DCEs). This paper responds to such calls by carefully reporting a systematic process of developing micro health insurance attributes and attribute-levels for the design of a DCE in rural Malawi. Methods Conceptual attributes and attribute-levels were initially derived from a literature review which informed the design of qualitative data collection tools to identify context specific attributes and attribute-levels. Qualitative data was collected in August-September 2012 from 12 focus group discussions with community residents and 8 in-depth interviews with health workers. All participants were selected according to stratified purposive sampling. The material was tape-recorded, fully transcribed, and coded by three researchers to identify context-specific attributes and attribute-levels. Expert opinion was used to scale down the attributes and levels. A pilot study confirmed the appropriateness of the selected attributes and levels for a DCE. Results First, a consensus, emerging from an individual level analysis of the qualitative transcripts, identified 10 candidate attributes. Levels were assigned to all attributes based on data from transcripts and knowledge of the Malawian context, derived from literature. Second, through further discussions with experts, four attributes were discarded based on multiple criteria. The 6 remaining attributes were: premium level, unit of enrollment, management structure, health service benefit package, transportation coverage and copayment levels. A final

  11. Developing attributes and attribute-levels for a discrete choice experiment on micro health insurance in rural Malawi.

    PubMed

    Abiiro, Gilbert Abotisem; Leppert, Gerald; Mbera, Grace Bongololo; Robyn, Paul J; De Allegri, Manuela

    2014-05-22

    Discrete choice experiments (DCEs) are attribute-driven experimental techniques used to elicit stakeholders' preferences to support the design and implementation of policy interventions. The validity of a DCE, therefore, depends on the appropriate specification of the attributes and their levels. There have been recent calls for greater rigor in implementing and reporting on the processes of developing attributes and attribute-levels for discrete choice experiments (DCEs). This paper responds to such calls by carefully reporting a systematic process of developing micro health insurance attributes and attribute-levels for the design of a DCE in rural Malawi. Conceptual attributes and attribute-levels were initially derived from a literature review which informed the design of qualitative data collection tools to identify context specific attributes and attribute-levels. Qualitative data was collected in August-September 2012 from 12 focus group discussions with community residents and 8 in-depth interviews with health workers. All participants were selected according to stratified purposive sampling. The material was tape-recorded, fully transcribed, and coded by three researchers to identify context-specific attributes and attribute-levels. Expert opinion was used to scale down the attributes and levels. A pilot study confirmed the appropriateness of the selected attributes and levels for a DCE. First, a consensus, emerging from an individual level analysis of the qualitative transcripts, identified 10 candidate attributes. Levels were assigned to all attributes based on data from transcripts and knowledge of the Malawian context, derived from literature. Second, through further discussions with experts, four attributes were discarded based on multiple criteria. The 6 remaining attributes were: premium level, unit of enrollment, management structure, health service benefit package, transportation coverage and copayment levels. A final step of revision and piloting

  12. Testing Cessation Messages for Cigarette Package Inserts: Findings from a Best/Worst Discrete Choice Experiment

    PubMed Central

    Thrasher, James F.; Davis, Rachel E.; Popova, Lucy; Cho, Yoo Jin; Salloum, Ramzi G.; Louviere, Jordan; Hammond, David

    2018-01-01

    This study assessed smokers’ responses to different smoking cessation topics and imagery for cigarette package inserts. Adult smokers from Canada (n = 1000) participated in three discrete choice experiments (DCEs): DCE 1 assessed five cessation benefit topics and five imagery types; DCE 2 assessed five messages with tips to improve cessation success and five imagery types; DCE 3 assessed four reproductive health benefits of cessation topics and four imagery types. In each DCE, participants evaluated four or five sets of four inserts, selecting the most and least motivating (DCEs 1 & 3) or helpful (DCE 2) for quitting. Linear mixed models regressed choices on insert and smoker characteristics. For DCE 1, the most motivating messages involved novel disease topics and imagery of younger women. For DCE 2, topics of social support, stress reduction and nicotine replacement therapy were selected as most helpful, with no differences by imagery type. For DCE 3, imagery influenced choices more than topic, with imagery of a family or a mom and baby selected as most motivating. Statistically significant interactions for all three experiments indicated that the influence of imagery type on choices depended on the message topic. Messages to promote smoking cessation through cigarette pack inserts should consider specific combinations of message topic and imagery. PMID:29415523

  13. Prioritising health service innovation investments using public preferences: a discrete choice experiment.

    PubMed

    Erdem, Seda; Thompson, Carl

    2014-08-28

    Prioritising scarce resources for investment in innovation by publically funded health systems is unavoidable. Many healthcare systems wish to foster transparency and accountability in the decisions they make by incorporating the public in decision-making processes. This paper presents a unique conceptual approach exploring the public's preferences for health service innovations by viewing healthcare innovations as 'bundles' of characteristics. This decompositional approach allows policy-makers to compare numerous competing health service innovations without repeatedly administering surveys for specific innovation choices. A Discrete Choice Experiment (DCE) was used to elicit preferences. Individuals chose from presented innovation options that they believe the UK National Health Service (NHS) should invest the most in. Innovations differed according to: (i) target population; (ii) target age; (iii) implementation time; (iv) uncertainty associated with their likely effects; (v) potential health benefits; and, (vi) cost to a taxpayer. This approach fosters multidimensional decision-making, rather than imposing a single decision criterion (e.g., cost, target age) in prioritisation. Choice data was then analysed using scale-adjusted Latent Class models to investigate variability in preferences and scale and valuations amongst respondents. Three latent classes with considerable heterogeneity in the preferences were present. Each latent class is composed of two consumer subgroups varying in the level of certainty in their choices. All groups preferred scientifically proven innovations, those with potential health benefits that cost less. There were, however, some important differences in their preferences for innovation investment choices: Class-1 (54%) prefers innovations benefitting adults and young people and does not prefer innovations targeting people with 'drug addiction' and 'obesity'. Class- 2 (34%) prefers innovations targeting 'cancer' patients only and has

  14. Perceived risk and modal choice: risk compensation in transportation systems.

    PubMed

    Noland, R B

    1995-08-01

    A transportation mode choice analysis is performed that examines behavioral responses to perceived risk in the choice of mode for daily commute trips. This methodology provides a technique for examining, by means of disaggregate individual level data, risk-compensating effects in transportation systems. Various measures of perceived risk are examined for explaining modal choice. Other studies have described how safety regulations have resulted in increases in "driving intensity." This study defines one component of driving intensity to be the increased probability of commuting by automobile. The results show that modal shifts occur when risk perceptions for a given mode are reduced. To demonstrate potential risk-compensating effects within the transportation system, an estimate of changes in accident fatalities due to commuting is derived using rough estimates of fatalities per person-mile travelled. It is shown that a given change in the perceived risk of commuting by automobile results in a less than proportionate change in net commuting fatalities. The relative magnitude is dependent on how objective reductions in risk translate into perceived reductions in risk. This study also shows that perceived safety improvements in bicycle transportation have an aggregate elasticity value that is greater than one. This means that bicycle safety improvements attract proportionately more people to bicycle commuting (i.e. a 10% increase in safety results in a greater than 10% increase in the share of people bicycle commuting).

  15. Discrete choice experiment of smoking cessation behaviour in Japan.

    PubMed

    Goto, Rei; Nishimura, Shuzo; Ida, Takanori

    2007-10-01

    In spite of gradual increases in tobacco price and the introduction of laws supporting various anti-tobacco measures, the proportion of smokers in Japan's population is still higher than in other developed nations. To understand what information and individual characteristics drive smokers to attempt to quit smoking. These determinants will help to realise effective tobacco control policy as a base for understanding of cessation behaviour. Discrete choice experiments on a total of 616 respondents registered at a consumer monitoring investigative company. The effect of price is greater on smokers with lower nicotine dependence. For smokers of moderate and low dependency, short term health risks and health risks caused by passive smoking have a strong impact, though the existence of penalties and long term health risks have little influence on smokers' decisions to quit. For highly dependent smokers, non-price attributes have little impact. Furthermore, the effects of age, sex and knowledge are also not uniform in accounting for smoking cessation. Determinants of smoking cessation vary among levels of nicotine dependency. Therefore, how and what information is provided needs to be carefully considered when counselling smokers to help them to quit.

  16. Discrete choice experiment of smoking cessation behaviour in Japan

    PubMed Central

    Goto, Rei; Nishimura, Shuzo; Ida, Takanori

    2007-01-01

    Background In spite of gradual increases in tobacco price and the introduction of laws supporting various anti‐tobacco measures, the proportion of smokers in Japan's population is still higher than in other developed nations. Objective To understand what information and individual characteristics drive smokers to attempt to quit smoking. These determinants will help to realise effective tobacco control policy as a base for understanding of cessation behaviour. Method Discrete choice experiments on a total of 616 respondents registered at a consumer monitoring investigative company. Results The effect of price is greater on smokers with lower nicotine dependence. For smokers of moderate and low dependency, short term health risks and health risks caused by passive smoking have a strong impact, though the existence of penalties and long term health risks have little influence on smokers' decisions to quit. For highly dependent smokers, non‐price attributes have little impact. Furthermore, the effects of age, sex and knowledge are also not uniform in accounting for smoking cessation. Conclusion Determinants of smoking cessation vary among levels of nicotine dependency. Therefore, how and what information is provided needs to be carefully considered when counselling smokers to help them to quit. PMID:17897993

  17. Criteria for prioritization of HIV programs in Viet Nam: a discrete choice experiment.

    PubMed

    Safarnejad, Ali; Pavlova, Milena; Son, Vo Hai; Phuong, Huynh Lan; Groot, Wim

    2017-11-13

    With the decline in funding for Viet Nam's response to the HIV epidemic, there is a need for evidence on the criteria to guide the prioritization of HIV programs. There is a gap in the research on the relative importance of multiple criteria for prioritizing a package of interventions. This study elicits preferences and the trade-offs made between different HIV programs by relevant stakeholders and decision-makers in Viet Nam. It also pays attention to how differences in social and professional characteristics of stakeholders and their agency affiliations shape preferences for HIV program criteria in Viet Nam. This study uses self-explicated ranking and discrete choice experiments to determine the relative importance of five criteria - effectiveness, feasibility, cost-effectiveness, rate of investment and prevention/treatment investment ratio - to stakeholders when they evaluate and select hypothetical HIV programs. The study includes 69 participants from government, civil society, and international development partners. Results of the discrete choice experiment show that overall the feasibility criterion is ranked highest in importance to the participants when choosing a hypothetical HIV program, followed by sustainability, treatment to prevention spending ratio, and effectiveness. The participant's work in management, programming, or decision-making has a significant effect on the importance of some criteria to the participant. In the self-explicated ranking effectiveness is the most important criterion and the cost-effectiveness criterion ranks low in importance across all groups. This study has shown that the preferred HIV program in Viet Nam is feasible, front-loaded for sustainability, has a higher proportion of investment on prevention, saves more lives and prevents more infections. Similarities in government and civil society rankings of criteria can create common grounds for future policy dialogues between stakeholders. Innovative models of planning should

  18. Numerical Experiments on Advective Transport in Large Three-Dimensional Discrete Fracture Networks

    NASA Astrophysics Data System (ADS)

    Makedonska, N.; Painter, S. L.; Karra, S.; Gable, C. W.

    2013-12-01

    Modeling of flow and solute transport in discrete fracture networks is an important approach for understanding the migration of contaminants in impermeable hard rocks such as granite, where fractures provide dominant flow and transport pathways. The discrete fracture network (DFN) model attempts to mimic discrete pathways for fluid flow through a fractured low-permeable rock mass, and may be combined with particle tracking simulations to address solute transport. However, experience has shown that it is challenging to obtain accurate transport results in three-dimensional DFNs because of the high computational burden and difficulty in constructing a high-quality unstructured computational mesh on simulated fractures. An integrated DFN meshing [1], flow, and particle tracking [2] simulation capability that enables accurate flow and particle tracking simulation on large DFNs has recently been developed. The new capability has been used in numerical experiments on advective transport in large DFNs with tens of thousands of fractures and millions of computational cells. The modeling procedure starts from the fracture network generation using a stochastic model derived from site data. A high-quality computational mesh is then generated [1]. Flow is then solved using the highly parallel PFLOTRAN [3] code. PFLOTRAN uses the finite volume approach, which is locally mass conserving and thus eliminates mass balance problems during particle tracking. The flow solver provides the scalar fluxes on each control volume face. From the obtained fluxes the Darcy velocity is reconstructed for each node in the network [4]. Velocities can then be continuously interpolated to any point in the domain of interest, thus enabling random walk particle tracking. In order to describe the flow field on fractures intersections, the control volume cells on intersections are split into four planar polygons, where each polygon corresponds to a piece of a fracture near the intersection line. Thus

  19. Patient Preferences for Managing Insomnia: A Discrete Choice Experiment.

    PubMed

    Cheung, Janet M Y; Bartlett, Delwyn J; Armour, Carol L; Saini, Bandana; Laba, Tracey-Lea

    2018-03-03

    Despite the rapid development of effective treatments, both pharmacological and non-pharmacological, insomnia management remains suboptimal at the practice interface. Patient preferences play a critical role in influencing treatment outcomes. However, there is currently a mismatch between patient preferences and clinician recommendations, partly perpetuated by a limited understanding of the patients' decision-making process. The aim of our study was to empirically quantify patient preferences for treatment attributes common to both pharmacological and non-pharmacological insomnia treatments. An efficient dual-response discrete choice experiment was conducted to evaluate patient treatment preferences for managing insomnia. The sample included 205 patients with self-reported insomnia and an Insomnia Severity Index ≥ 14. Participants were presented with two unlabelled hypothetical scenarios with an opt-out option across 12 choice sets. Data were analyzed using a mixed multinomial logit model to investigate the influence of five attributes (i.e. time, onset of action, maintainability of improved sleep, length of treatment, and monthly cost) on treatment preferences. Treatments were preferentially viewed if they conferred long-term sleep benefits (p < 0.05); had an ongoing, as opposed to a predefined, duration of treatment course (p < 0.05); required some, as opposed to no, additional time commitment (p < 0.05); and had lower monthly out-of-pocket treatment costs (p < 0.001). However, treatment onset of action had no influence on preference. Age, help-seeking status, concession card status and fatigue severity significantly influenced treatment preference. Participants' prioritization of investing time in treatment and valuing the maintainability of therapeutic gains suggests a stronger inclination towards non-pharmacological treatment, defying current assumptions that patients prefer 'quick-fixes' for managing insomnia.

  20. Discrete-choice experiment to measure patient preferences for the surgical management of colorectal cancer.

    PubMed

    Salkeld, G; Solomon, M; Butow, P; Short, L

    2005-06-01

    Establishing trust between a patient and his or her surgeon is of paramount importance. The aim of this study was to assess the relative importance of the 'attributes of trust' between surgeon and patient with colorectal cancer. A discrete-choice questionnaire was conducted with 60 men and 43 women who had completed primary treatment for colorectal cancer in two teaching hospitals in Sydney, Australia. Forty-seven of the 103 patients based their choice of surgical management on a single attribute and the remainder were willing to trade between different attributes. In order of importance, patients based their choice of surgical management on specialty training (beta coefficient = 0.83), surgeon's communication (beta = 0.82), type of hospital (beta = 0.72) and who decides treatment (beta = 0.01). Patients who were vigilant in their decision-making style and those who did not have tertiary education were more likely to change their preferences in the repeat interview. Clinicians may have a better chance of meeting a patient's expectations about the process of care if they assess the patient's desire for knowledge and give those who do not have tertiary education more time to assimilate information about their treatment. Copyright (c) 2005 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.

  1. Women's and healthcare professionals' preferences for prenatal testing: a discrete choice experiment.

    PubMed

    Beulen, Lean; Grutters, Janneke P C; Faas, Brigitte H W; Feenstra, Ilse; Groenewoud, Hans; van Vugt, John M G; Bekker, Mireille N

    2015-06-01

    This study evaluates pregnant women's and healthcare professionals' preferences regarding specific prenatal screening and diagnostic test characteristics. A discrete choice experiment was developed to assess preferences for prenatal tests that differed in seven attributes: minimal gestational age, time to test results, level of information, detection rate, false positive rate, miscarriage risk and costs. The questionnaire was completed by 596 (70.2%) pregnant women and 297 (51.7%) healthcare professionals, of whom 507 (85.1%) and 283 (95.3%), respectively, were included in further analyses as their choice behavior indicated prenatal testing was an option to them. Comparison of results showed differences in relative importance attached to attributes, further reflected by differences in willingness to trade between attributes. Pregnant women are willing to accept a less accurate test to obtain more information on fetal chromosomal status or to exclude the risk of procedure-related miscarriage. Healthcare professionals consider level of information and miscarriage risk to be most important as well but put more emphasis on timing and accuracy. Pregnant women and healthcare professionals differ significantly in their preferences regarding prenatal test characteristics. Healthcare professionals should take these differences into consideration when counseling pregnant women on prenatal testing. © 2015 John Wiley & Sons, Ltd.

  2. Patient Preferences for Features of Health Care Delivery Systems: A Discrete Choice Experiment.

    PubMed

    Mühlbacher, Axel C; Bethge, Susanne; Reed, Shelby D; Schulman, Kevin A

    2016-04-01

    To estimate the relative importance of organizational-, procedural-, and interpersonal-level features of health care delivery systems from the patient perspective. We designed four discrete choice experiments (DCEs) to measure patient preferences for 21 health system attributes. Participants were recruited through the online patient portal of a large health system. We analyzed the DCE data using random effects logit models. DCEs were performed in which respondents were provided with descriptions of alternative scenarios and asked to indicate which scenario they prefer. Respondents were randomly assigned to one of the three possible health scenarios (current health, new lung cancer diagnosis, or diabetes) and asked to complete 15 choice tasks. Each choice task included an annual out-of-pocket cost attribute. A total of 3,900 respondents completed the survey. The out-of-pocket cost attribute was considered the most important across the four different DCEs. Following the cost attribute, trust and respect, multidisciplinary care, and shared decision making were judged as most important. The relative importance of out-of-pocket cost was consistently lower in the hypothetical context of a new lung cancer diagnosis compared with diabetes or the patient's current health. This study demonstrates the complexity of patient decision making processes regarding features of health care delivery systems. Our findings suggest the importance of these features may change as a function of an individual's medical conditions. © Health Research and Educational Trust.

  3. Discrete-choice modelling of patient preferences for modes of drug administration.

    PubMed

    Tetteh, Ebenezer Kwabena; Morris, Steve; Titcheneker-Hooker, Nigel

    2017-12-01

    The administration of (biologically-derived) drugs for various disease conditions involves consumption of resources that constitutes a direct monetary cost to healthcare payers and providers. An often ignored cost relates to a mismatch between patients' preferences and the mode of drug administration. The "intangible" benefits of giving patients what they want in terms of the mode of drug delivery is seldom considered. This study aims to evaluate, in monetary terms, end-user preferences for the non-monetary attributes of different modes of drug administration using a discrete-choice experiment. It provides empirical support to the notion that there are significant benefits from developing patient-friendly approaches to drug delivery. The gross benefits per patient per unit administration is in the same order of magnitude as the savings in resource costs of administering drugs. The study argues that, as long as the underlying manufacturing science is capable, a patient-centred approach to producing drug delivery systems should be encouraged and pursued.

  4. Qualitative Development of a Discrete Choice Experiment for Physical Activity Interventions to Improve Knee Osteoarthritis.

    PubMed

    Pinto, Daniel; Danilovich, Margaret K; Hansen, Paul; Finn, Daniel J; Chang, Rowland W; Holl, Jane L; Heinemann, Allen W; Bockenholt, Ulf

    2017-06-01

    To describe the qualitative process used to develop attributes and attribute levels for inclusion in a discrete choice experiments (DCE) for older adult physical activity interventions. Five focus groups (n=41) were conducted, grounded in the Health Action Process Approach framework. Discussion emphasized identification and prioritization attributes for a DCE on physical activity. Semi-structured interviews (n=6) investigated attribute levels and lay-language for the DCE. A focus group with physical activity researchers and health care providers was the final stakeholder group used to establish a comprehensive approach for the generation of attributes and levels. A DCE pilot test (n=8) was then conducted with individuals of the target patient population. All transcripts were analyzed using a constant comparative approach. General community and university-based research setting. Volunteers (N=55) aged >45 years with knee pain, aches, or stiffness for at least 1 month over the previous 12 months. Not applicable. Interview guides, attributes, attribute levels, and discrete choice experiment. The most influential identified attributes for physical activity were time, effort, cost, convenience, enjoyment, and health benefits. Each attribute had 3 levels that were understandable in the pilot test of the DCE. The identification of 6 physical activity attributes that are most salient to adults with knee osteoarthritis resulted from a systematic qualitative process, including attribute-ranking exercises. A DCE will provide insight into the relative importance of these attributes for participating in physical activity, which can guide intervention development. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  5. Preferences for policy options for cannabis in an Australian general population: A discrete choice experiment.

    PubMed

    Shanahan, Marian; Gerard, Karen; Ritter, Alison

    2014-07-01

    Policy choices for illicit drugs such as cannabis entail consideration of competing factors such as individual health, societal views about pleasure, and criminal justice impacts. Society must weigh up these factors in determining the preferred cannabis policy; although often cast as a contest between legalisation of cannabis or full prohibition the actual policy choices are not so black and white. This study assessed societal preferences for different cannabis policies and multiple consequences. A discrete choice experiment (DCE) quantified value-based preferences for alternative cannabis policies described by the five key attributes legal status, health harms, criminal justice service costs, rates of cannabis use and purchase location. An online survey was conducted on a population sample of 1020 Australians. The analytical model was based on stated choices for Policy A, B or Current Policy. The results revealed a strong general preference for either civil penalties or legalisation compared to cannabis cautioning (Current Policy) and a strong dislike of criminalising possession and use of cannabis. Results also demonstrate difference in preferences among those with different demographics and beliefs. Understanding these nuances help to quantify the range of preferences held within the population and can be used to inform policy. This is the first known DCE survey applied to the area of illicit drugs policy. It demonstrates the public hold disparate views on the most appropriate status for cannabis offences and they are able to make trade-offs between policy choices and outcomes in complex areas of social policy. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Environmental Factors in the Choice of EGMs: A Discrete Choice Experiment.

    PubMed

    Rockloff, Matthew J; Moskovsky, Neda; Thorne, Hannah; Browne, Matthew; Bryden, Gabrielle M

    2017-09-01

    EGMs are a form of entertainment, and the gambling environment is an important contributor to the overall experience. Logically, to select a play-environment, EGM gamblers must choose the platform through which to access the EGM (e.g., internet, mobile application or land-based venue), a particular provider (e.g., specific website, app vendor or branded casino), and the game itself (e.g., based on graphical theme or bonus features; Thorne et al. in J Gambl Stud, 2016. doi: 10.1007/s10899-016-9601-2 ). A discrete choice experiment was conducted to identify the features of the platform, provider and game that are most strongly preferred by EGM gamblers. Participants were 245 EGM gamblers from clubs in Victoria, Australia and 7516 EGM gamblers from an Australian online panel. Results indicate that the ideal environment for the average gambler consists of: gambling at a club that is close to home; with a group of friends; in a relatively quiet place that has air conditioning, cheap food and a large space to play in; on a classic game with quality animations and small bet sizes; where you feel safe and secure; and where there is a wide variety of other games to play when you are done. Segmenting these results by problem-gambler status highlights important differences in preferences between problem and non-problem gamblers. Problem gamblers are less likely to give weight to the company they share and have a preference for larger venues. Using a powerful paradigm from marketing research, the present study was able to determine the relative value of different features of the EGM gambling environment, and also contributes important insight towards what constitutes a safer environment for recreational play.

  7. Prioritising wheelchair services for children: a pilot discrete choice experiment to understand how child wheelchair users and their parents prioritise different attributes of wheelchair services.

    PubMed

    Bray, Nathan; Yeo, Seow Tien; Noyes, Jane; Harris, Nigel; Edwards, Rhiannon Tudor

    2016-01-01

    Approximately 95 million children worldwide are disabled; 10 % use a wheelchair. In the UK, an estimated 770,000 children are disabled. National Health Service Wheelchair Services are the largest provider of wheelchairs in the UK; however, recent reports have highlighted issues with these services. This study explores the use of discrete choice experiment methods to inform wheelchair service provision for disabled children based on service user preferences. The aim was to explore how disabled children and their parents prioritise different attributes of wheelchair services. The secondary aims were to compare priorities between parents and disabled children and to explore marginal rate of substitution for incremental changes in attributes. Discrete choice experiments are a method of attribute-based stated preference valuation used by health economists to understand how individuals prioritise different attributes of healthcare services and treatments. We conducted the first pilot discrete choice experiment to explore how disabled children (aged 11 to 18) and their parents prioritise different attributes of hypothetical wheelchair services. Eleven disabled children (aged 11 to 18) and 30 parents of disabled children completed eight pairwise choice tasks based on five service attributes: wheelchair assessment, cost contribution, training, delivery time and frequency of review. Data were analysed using conditional logistic regression. For each pairwise choice, the participants were asked to choose which service scenario (A or B) they preferred. Comprehensiveness of wheelchair assessment and wheelchair delivery time significantly ( P  < 0.05) affected service preferences of children ( β -coefficients = 1.43 [95 % bootstrapped CI = 1.42 to 2.08] and -0.92 [95 % bootstrapped CI = -1.41 to -0.84], respectively) and parents ( β -coefficients = 1.53 [95 % bootstrapped CI = 1.45 to 2.16] and -1.37 [95 % bootstrapped CI = -1.99 to -1

  8. Incorporating environmental attitudes in discrete choice models: an exploration of the utility of the awareness of consequences scale.

    PubMed

    Hoyos, David; Mariel, Petr; Hess, Stephane

    2015-02-01

    Environmental economists are increasingly interested in better understanding how people cognitively organise their beliefs and attitudes towards environmental change in order to identify key motives and barriers that stimulate or prevent action. In this paper, we explore the utility of a commonly used psychometric scale, the awareness of consequences (AC) scale, in order to better understand stated choices. The main contribution of the paper is that it provides a novel approach to incorporate attitudinal information into discrete choice models for environmental valuation: firstly, environmental attitudes are incorporated using a reinterpretation of the classical AC scale recently proposed by Ryan and Spash (2012); and, secondly, attitudinal data is incorporated as latent variables under a hybrid choice modelling framework. This novel approach is applied to data from a survey conducted in the Basque Country (Spain) in 2008 aimed at valuing land-use policies in a Natura 2000 Network site. The results are relevant to policy-making because choice models that are able to accommodate underlying environmental attitudes may help in designing more effective environmental policies. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. German travelers' preferences for travel vaccines assessed by a discrete choice experiment.

    PubMed

    Poulos, Christine; Curran, Desmond; Anastassopoulou, Anastassia; De Moerlooze, Laurence

    2018-02-08

    Many travelers to regions with endemic infectious diseases do not follow health authorities' recommendations regarding vaccination against vaccine-preventable infectious diseases, before traveling. The determinants of individual travelers' decisions to vaccinate before traveling are largely unknown. This study aimed to provide this information using a discrete choice experiment (DCE) administered to four types of German travelers: (1) business travelers; (2) travelers visiting friends and relatives (VFR); (3) leisure travelers; and (4) backpackers. A DCE survey was developed, pretested and administered online. It included a series of choice questions in which respondents chose between two hypothetical vaccines, each characterized by four disease attributes with varying levels describing the of risk, health impact, curability and transmissibility of the disease they would prevent (described with four disease attributes with varying levels of risk, health impact, curability and transmissibility), and varying levels of four vaccine attributes (duration of protection, number of doses required, time required for vaccination, and vaccine cost). A random-parameters logit model was used to estimate the importance weights each traveler type placed on the various attribute levels. These weights were used to calculate mean monetary equivalents (MMEs) of changes in each attribute (holding all others constant) and of hypothetical disease-vaccine combinations. All traveler types' choices indicated that they attached the greatest importance to the risk and health impact of disease and to the vaccine cost whereas the other disease and vaccine attributes were less important for their decisions about travel vaccines. An option of not choosing any of the vaccine-pairs presented was rarely selected indicating that travelers' generally prefer to be vaccinated rather than not. The MMEs of changes in vaccine attributes indicated a very high variability between the individual travelers

  10. GPU accelerated simulations of 3D deterministic particle transport using discrete ordinates method

    NASA Astrophysics Data System (ADS)

    Gong, Chunye; Liu, Jie; Chi, Lihua; Huang, Haowei; Fang, Jingyue; Gong, Zhenghu

    2011-07-01

    Graphics Processing Unit (GPU), originally developed for real-time, high-definition 3D graphics in computer games, now provides great faculty in solving scientific applications. The basis of particle transport simulation is the time-dependent, multi-group, inhomogeneous Boltzmann transport equation. The numerical solution to the Boltzmann equation involves the discrete ordinates ( Sn) method and the procedure of source iteration. In this paper, we present a GPU accelerated simulation of one energy group time-independent deterministic discrete ordinates particle transport in 3D Cartesian geometry (Sweep3D). The performance of the GPU simulations are reported with the simulations of vacuum boundary condition. The discussion of the relative advantages and disadvantages of the GPU implementation, the simulation on multi GPUs, the programming effort and code portability are also reported. The results show that the overall performance speedup of one NVIDIA Tesla M2050 GPU ranges from 2.56 compared with one Intel Xeon X5670 chip to 8.14 compared with one Intel Core Q6600 chip for no flux fixup. The simulation with flux fixup on one M2050 is 1.23 times faster than on one X5670.

  11. Incentives for Blood Donation: A Discrete Choice Experiment to Analyze Extrinsic Motivation.

    PubMed

    Sadler, Andrew; Shi, Ling; Bethge, Susanne; Mühlbacher, Axel

    2018-04-01

    Background: Demographic trends affect size and age structure of populations. One of the consequences will be an increasing need for blood products to treat age-related diseases. Donation services rely on voluntariness and charitable motivation. It might be questioned whether there will be sufficient blood supply with voluntary donation. The present study focused on elicitation of preferences for incentives and aimed to contribute to the discussion on how to increase donation rates. Methods: A self-administered discrete choice experiment (DCE) was applied. Respondents were repeatedly asked to choose between hypothetical blood donation centers. In case of reluctance to receiving incentives a none-option was included. Random parameter logit (RPL) and latent class models (LCM) were used for analysis. Results: The study sample included 416 college students from the US and Germany. Choice decisions were significantly influenced by the characteristics of the donation center in the DCE. Incentives most preferred were monetary compensation, paid leave, and blood screening test. LCM identified subgroups with preference heterogeneity. Small subgroups indicated moderate to strong aversion to incentives. Conclusion: The majority of the sample positively responded to incentives and indicated a willingness to accept incentives. In face of future challenges, the judicious use and appropriate utilization of incentives might be an option to motivate potential donors and should be open to discussion.

  12. Preferences for long-term care services: willingness to pay estimates derived from a discrete choice experiment.

    PubMed

    Nieboer, Anna P; Koolman, Xander; Stolk, Elly A

    2010-05-01

    Ageing populations increase pressure on long-term care. Optimal resource allocation requires an optimal mix of care services based on costs and benefits. Contrary to costs, benefits remain largely unknown. This study elicits preferences in the general elderly population for long-term care services for varying types of patients. A discrete choice experiment was conducted in a general population subsample aged 50-65 years (N = 1082) drawn from the Dutch Survey Sampling International panel. To ascertain relative preferences for long-term care and willingness to pay for these, participants were asked to choose the best of two care scenarios for four groups of hypothetical patients: frail and demented elderly, with and without partner. The scenarios described long-term care using ten attributes based on Social Production Function theory: hours of care, organized social activities, transportation, living situation, same person delivering care, room for individual preferences, coordination of services, punctuality, time on waiting list, and co-payments. We found the greatest value was attached to same person delivering care and transportation services. Low value was attached to punctuality and room for individual preferences. Nursing homes were generally considered to be detrimental for well-being except for dementia patients without a partner. Overall, long-term care services were thought to produce greatest well-being for the patients 'without a partner' and those 'with dementia'. Individuals combining these two risk factors would benefit the most from all services except transportation which was considered more important for the frail elderly. The results support the notion that long-term care services represent different value for different types of patients and that the value of a service depends upon the social context. Examination of patient profiles confirmed the notion that physical, mental and social vulnerability affect valuation of the services. Policy

  13. Patient preferences for community pharmacy asthma services: a discrete choice experiment.

    PubMed

    Naik-Panvelkar, Pradnya; Armour, Carol; Rose, John M; Saini, Bandana

    2012-10-01

    Specialized community pharmacy services, involving the provision of disease state management and care by pharmacists, have been developed and trialled and have demonstrated very good health outcomes. Most of these services have been developed from a healthcare professional perspective. However, for the future uptake and long-term sustainability of these services as well as for better and sustained health outcomes for patients, it is vital to gain an understanding of patients' preferences. We can then structure healthcare services to match these preferences and needs rather than around clinical viewpoints alone. The aim of this study was to elicit patient preferences for pharmacy-based specialized asthma services using a discrete choice experiment and to explore the value/importance that patients place on the different attributes of the asthma service. The existence of preference heterogeneity in the population was also investigated. The study was conducted with asthma patients who had recently experienced a specialized asthma management service at their pharmacy in New South Wales, Australia. Pharmacists delivering the asthma service mailed out the discrete choice questionnaires to participating patients at the end of 6 months of service provision. A latent class (LC) model was used to investigate each patient's strength of preference and preference heterogeneity for several key attributes related to asthma service provision: frequency of visits, access to pharmacist, interaction with pharmacy staff, availability of a private area for consultation, provision of lung function testing, type and depth of advice provision, number of days with asthma symptoms and cost of service. Eighty useable questionnaires (of 170 questionnaires sent out) were received (response rate 47.1%). The study identified various key elements of asthma services important to patients. Further, the LC analysis revealed three classes with differing patient preferences for levels of asthma service

  14. Preferences for breast cancer risk reduction among BRCA1/BRCA2 mutation carriers: a discrete-choice experiment.

    PubMed

    Liede, Alexander; Mansfield, Carol A; Metcalfe, Kelly A; Price, Melanie A; Snyder, Carrie; Lynch, Henry T; Friedman, Sue; Amelio, Justyna; Posner, Joshua; Narod, Steven A; Lindeman, Geoffrey J; Evans, D Gareth

    2017-09-01

    Unaffected women who carry BRCA1 or BRCA2 mutations face difficult choices about reducing their breast cancer risk. Understanding their treatment preferences could help us improve patient counseling and inform drug trials. The objective was to explore preferences for various risk-reducing options among women with germline BRCA1/2 mutations using a discrete-choice experiment survey and to compare expressed preferences with actual behaviors. A discrete-choice experiment survey was designed wherein women choose between hypothetical treatments to reduce breast cancer risk. The hypothetical treatments were characterized by the extent of breast cancer risk reduction, treatment duration, impact on fertility, hormone levels, risk of uterine cancer, and ease and mode of administration. Data were analyzed using a random-parameters logit model. Women were also asked to express their preference between surgical and chemoprevention options and to report on their actual risk-reduction actions. Women aged 25-55 years with germline BRCA1/2 mutations who were unaffected with breast or ovarian cancer were recruited through research registries at five clinics and a patient advocacy group. Between January 2015 and March 2016, 622 women completed the survey. Breast cancer risk reduction was the most important consideration expressed, followed by maintaining fertility. Among the subset of women who wished to have children in future, the ability to maintain fertility was the most important factor, followed by the extent of risk reduction. Many more women said they would take a chemoprevention drug than had actually taken chemoprevention. Women with BRCA1/2 mutations indicated strong preferences for breast cancer risk reduction and maintaining fertility. The expressed desire to have a safe chemoprevention drug available to them was not met by current chemoprevention options.

  15. Discretization of 3d gravity in different polarizations

    NASA Astrophysics Data System (ADS)

    Dupuis, Maïté; Freidel, Laurent; Girelli, Florian

    2017-10-01

    We study the discretization of three-dimensional gravity with Λ =0 following the loop quantum gravity framework. In the process, we realize that different choices of polarization are possible. This allows us to introduce a new discretization based on the triad as opposed to the connection as in the standard loop quantum gravity framework. We also identify the classical nontrivial symmetries of discrete gravity, namely the Drinfeld double, given in terms of momentum maps. Another choice of polarization is given by the Chern-Simons formulation of gravity. Our framework also provides a new discretization scheme of Chern-Simons, which keeps track of the link between the continuum variables and the discrete ones. We show how the Poisson bracket we recover between the Chern-Simons holonomies allows us to recover the Goldman bracket. There is also a transparent link between the discrete Chern-Simons formulation and the discretization of gravity based on the connection (loop gravity) or triad variables (dual loop gravity).

  16. Perceived Risks Contra Benefits of Using Biosimilar Drugs in Ulcerative Colitis: Discrete Choice Experiment among Gastroenterologists.

    PubMed

    Baji, Petra; Gulácsi, László; Golovics, Petra A; Lovász, Barbara D; Péntek, Márta; Brodszky, Valentin; Rencz, Fanni; Lakatos, Péter L

    2016-09-01

    In middle-income countries, access to biological therapy is limited in ulcerative colitis in terms of the number of patients and the length of therapy. Because of their cost advantages, biosimilars have the potential to improve access to therapy, but physicians have concerns toward their use because of the lack of evidence from randomized clinical trials. To explore the preferences of gastroenterologists for biosimilar drugs in ulcerative colitis as well as to compare our results with results of previous studies on gastroenterologists' preferences toward biosimilars. A discrete choice experiment was carried out involving 51 Hungarian gastroenterologists treating patients with inflammatory bowel disease in May 2014 with the following attributes: type of treatment (biosimilar/originator), severity of disease, availability of continuous medicine supply, and the stopping rule (whether the treatment is covered after 12 months). A conditional logit model was used to estimate the probabilities of choosing a given profile. According to the results, the stopping rule was the most important attribute. The type of treatment mattered only for patients already on biologicals. The probabilities of choosing the biosimilar option with all the benefits offered in the discrete choice experiment over the originator option under the present reimbursement conditions are 85% for new patients and 63% for patients already treated. Most gastroenterologists have concerns about using biosimilars. They, however, are willing to consider the use of biosimilars if they could reallocate the potential savings to provide their patients better access to biological treatment. Copyright © 2016 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  17. Alternative-Specific and Case-Specific Factors Involved in the Decisions of Islamic School Teachers Affecting Teacher Retention: A Discrete Choice Experiment

    ERIC Educational Resources Information Center

    Abd-El-Hafez, Alaa Karem

    2015-01-01

    Teacher retention is a concern in all educational sectors in America. It is of special importance to Islamic schools, which tend to lack the resources necessary in recruiting and training new teachers. This dissertation addressed this problem in full-time Islamic schools in New York State by conducting a discrete choice experiment, which reflects…

  18. Simulation study to determine the impact of different design features on design efficiency in discrete choice experiments

    PubMed Central

    Vanniyasingam, Thuva; Cunningham, Charles E; Foster, Gary; Thabane, Lehana

    2016-01-01

    Objectives Discrete choice experiments (DCEs) are routinely used to elicit patient preferences to improve health outcomes and healthcare services. While many fractional factorial designs can be created, some are more statistically optimal than others. The objective of this simulation study was to investigate how varying the number of (1) attributes, (2) levels within attributes, (3) alternatives and (4) choice tasks per survey will improve or compromise the statistical efficiency of an experimental design. Design and methods A total of 3204 DCE designs were created to assess how relative design efficiency (d-efficiency) is influenced by varying the number of choice tasks (2–20), alternatives (2–5), attributes (2–20) and attribute levels (2–5) of a design. Choice tasks were created by randomly allocating attribute and attribute level combinations into alternatives. Outcome Relative d-efficiency was used to measure the optimality of each DCE design. Results DCE design complexity influenced statistical efficiency. Across all designs, relative d-efficiency decreased as the number of attributes and attribute levels increased. It increased for designs with more alternatives. Lastly, relative d-efficiency converges as the number of choice tasks increases, where convergence may not be at 100% statistical optimality. Conclusions Achieving 100% d-efficiency is heavily dependent on the number of attributes, attribute levels, choice tasks and alternatives. Further exploration of overlaps and block sizes are needed. This study's results are widely applicable for researchers interested in creating optimal DCE designs to elicit individual preferences on health services, programmes, policies and products. PMID:27436671

  19. Consumer preferences for health and nonhealth outcomes of health promotion: results from a discrete choice experiment.

    PubMed

    Alayli-Goebbels, Adrienne F G; Dellaert, Benedict G C; Knox, Stephanie A; Ament, André J H A; Lakerveld, Jeroen; Bot, Sandra D M; Nijpels, G; Severens, J L

    2013-01-01

    Health promotion (HP) interventions have outcomes that go beyond health. Such broader nonhealth outcomes are usually neglected in economic evaluation studies. To allow for their consideration, insights are needed into the types of nonhealth outcomes that HP interventions produce and their relative importance compared with health outcomes. This study explored consumer preferences for health and nonhealth outcomes of HP in the context of lifestyle behavior change. A discrete choice experiment was conducted among participants in a lifestyle intervention (n = 132) and controls (n = 141). Respondents made 16 binary choices between situations that can be experienced after lifestyle behavior change. The situations were described by 10 attributes: future health state value, start point of future health state, life expectancy, clothing size above ideal, days with sufficient relaxation, endurance, experienced control over lifestyle choices, lifestyle improvement of partner and/or children, monetary cost per month, and time cost per week. With the exception of "time cost per week" and "start point of future health state," all attributes significantly determined consumer choices. Thus, both health and nonhealth outcomes affected consumer choice. Marginal rates of substitution between the price attribute and the other attributes revealed that the attributes "endurance," "days with sufficient relaxation," and "future health state value" had the greatest impact on consumer choices. The "life expectancy" attribute had a relatively low impact and for increases of less than 3 years, respondents were not willing to trade. Health outcomes and nonhealth outcomes of lifestyle behavior change were both important to consumers in this study. Decision makers should respond to consumer preferences and consider nonhealth outcomes when deciding about HP interventions. Copyright © 2013 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All

  20. A discrete-choice experiment to determine patient preferences for injectable multiple sclerosis treatments in Germany.

    PubMed

    Poulos, Christine; Kinter, Elizabeth; Yang, Jui-Chen; Bridges, John F P; Posner, Joshua; Gleißner, Erika; Mühlbacher, Axel; Kieseier, Bernd

    2016-03-01

    The aim of this study was to assess the relative importance of features of a hypothetical injectable disease-modifying treatment for patients with multiple sclerosis using a discrete-choice experiment. German residents at least 18 years of age with a self-reported physician diagnosis of multiple sclerosis completed a 25-30 minute online discrete-choice experiment. Patients were asked to choose one of two hypothetical injectable treatments for multiple sclerosis, defined by different levels of six attributes (disability progression, the number of relapses in the next 4 years, injection time, frequency of injections, presence of flu-like symptoms, and presence of injection-site reactions). The data were analyzed using a random-parameters logit model. Of 202 adults who completed the survey, results from 189 were used in the analysis. Approximately 50% of all patients reported a diagnosis of relapsing-remitting multiple sclerosis, and 31% reported secondary progressive multiple sclerosis. Approximately 71% of patients had current or prior experience with injectable multiple sclerosis medication. Approximately 53% had experienced flu-like symptoms caused by their medication, and 47% had experienced mild injection-site reactions. At least one significant difference was seen between levels in all attributes, except injection time. The greatest change in relative importance between levels of an attribute was years until symptoms get worse from 1 to 4 years. The magnitude of this difference was about twice that of relapses in the next 4 years, frequency of injections, and flu-like symptoms. Most attributes examined in this experiment had an influence on patient preference. Patients placed a significant value on improvements in the frequency of dosing and disability progression. Results suggest that changes in injection frequency can be as important as changes in efficacy and safety attributes. Understanding which attributes of injectable therapies influence patient

  1. Preferences for physician services in Ukraine: a discrete choice experiment.

    PubMed

    Danyliv, Andriy; Pavlova, Milena; Gryga, Irena; Groot, Wim

    2015-01-01

    Evidence on preferences of Ukrainian consumers for healthcare improvements can help to design reforms that correspond to societal priorities. This study aims to elicit and to place monetary values on public preferences for out-patient physician services in Ukraine. The method of discrete choice experiment is used on a sample of 303 respondents, representative of the adult Ukrainian population. The random effect logit model with interactions provides the best fit for the data and is used to calculate the marginal willingness to pay (MWTP) for quality and access improvements. At a sample level, there is no clear preference to pay formally rather than informally or vice versa. We also do not find that visiting a general practitioner is preferred over direct access to a medical specialist. However, there are differences between population groups. Quality-related attributes of physician services appear important to respondents, especially the attitude of medical staff. Thus, interpersonal aspects of out-patient care should be given priority in decisions about investments in quality improvements. Other aspects, that is social quality and access, are important as well but their improvement brings fewer social gains. Measures should be taken to eradicate the informal payment channels and to strengthen the gate-keeping role of primary care. Copyright © 2014 John Wiley & Sons, Ltd.

  2. Improving the quality of discrete-choice experiments in health: how can we assess validity and reliability?

    PubMed

    Janssen, Ellen M; Marshall, Deborah A; Hauber, A Brett; Bridges, John F P

    2017-12-01

    The recent endorsement of discrete-choice experiments (DCEs) and other stated-preference methods by regulatory and health technology assessment (HTA) agencies has placed a greater focus on demonstrating the validity and reliability of preference results. Areas covered: We present a practical overview of tests of validity and reliability that have been applied in the health DCE literature and explore other study qualities of DCEs. From the published literature, we identify a variety of methods to assess the validity and reliability of DCEs. We conceptualize these methods to create a conceptual model with four domains: measurement validity, measurement reliability, choice validity, and choice reliability. Each domain consists of three categories that can be assessed using one to four procedures (for a total of 24 tests). We present how these tests have been applied in the literature and direct readers to applications of these tests in the health DCE literature. Based on a stakeholder engagement exercise, we consider the importance of study characteristics beyond traditional concepts of validity and reliability. Expert commentary: We discuss study design considerations to assess the validity and reliability of a DCE, consider limitations to the current application of tests, and discuss future work to consider the quality of DCEs in healthcare.

  3. Women's Preferences for Treatment of Perinatal Depression and Anxiety: A Discrete Choice Experiment.

    PubMed

    Ride, Jemimah; Lancsar, Emily

    2016-01-01

    Perinatal depression and anxiety (PNDA) are an international healthcare priority, associated with significant short- and long-term problems for women, their children and families. Effective treatment is available but uptake is suboptimal: some women go untreated whilst others choose treatments without strong evidence of efficacy. Better understanding of women's preferences for treatment is needed to facilitate uptake of effective treatment. To address this issue, a discrete choice experiment (DCE) was administered to 217 pregnant or postnatal women in Australia, who were recruited through an online research company and had similar sociodemographic characteristics to Australian data for perinatal women. The DCE investigated preferences regarding cost, treatment type, availability of childcare, modality and efficacy. Data were analysed using logit-based models accounting for preference and scale heterogeneity. Predicted probability analysis was used to explore relative attribute importance and policy change scenarios, including how these differed by women's sociodemographic characteristics. Cost and treatment type had the greatest impact on choice, such that a policy of subsidising effective treatments was predicted to double their uptake compared with the base case. There were differences in predicted uptake associated with certain sociodemographic characteristics: for example, women with higher educational attainment were more likely to choose effective treatment. The findings suggest policy directions for decision makers whose goal is to reduce the burden of PNDA on women, their children and families.

  4. Discrete Choice Model of Food Store Trips Using National Household Food Acquisition and Purchase Survey (FoodAPS).

    PubMed

    Hillier, Amy; Smith, Tony E; Whiteman, Eliza D; Chrisinger, Benjamin W

    2017-09-27

    Where households across income levels shop for food is of central concern within a growing body of research focused on where people live relative to where they shop, what they purchase and eat, and how those choices influence the risk of obesity and chronic disease. We analyzed data from the National Household Food Acquisition and Purchase Survey (FoodAPS) using a conditional logit model to determine where participants shop for food to be prepared and eaten at home and how individual and household characteristics of food shoppers interact with store characteristics and distance from home in determining store choice. Store size, whether or not it was a full-service supermarket, and the driving distance from home to the store constituted the three significant main effects on store choice. Overall, participants were more likely to choose larger stores, conventional supermarkets rather than super-centers and other types of stores, and stores closer to home. Interaction effects show that participants receiving Supplemental Nutrition Assistance Program (SNAP) were even more likely to choose larger stores. Hispanic participants were more likely than non-Hispanics to choose full-service supermarkets while White participants were more likely to travel further than non-Whites. This study demonstrates the value of explicitly spatial discrete choice models and provides evidence of national trends consistent with previous smaller, local studies.

  5. Discrete Choice Model of Food Store Trips Using National Household Food Acquisition and Purchase Survey (FoodAPS)

    PubMed Central

    Hillier, Amy; Smith, Tony E.; Whiteman, Eliza D.

    2017-01-01

    Where households across income levels shop for food is of central concern within a growing body of research focused on where people live relative to where they shop, what they purchase and eat, and how those choices influence the risk of obesity and chronic disease. We analyzed data from the National Household Food Acquisition and Purchase Survey (FoodAPS) using a conditional logit model to determine where participants shop for food to be prepared and eaten at home and how individual and household characteristics of food shoppers interact with store characteristics and distance from home in determining store choice. Store size, whether or not it was a full-service supermarket, and the driving distance from home to the store constituted the three significant main effects on store choice. Overall, participants were more likely to choose larger stores, conventional supermarkets rather than super-centers and other types of stores, and stores closer to home. Interaction effects show that participants receiving Supplemental Nutrition Assistance Program (SNAP) were even more likely to choose larger stores. Hispanic participants were more likely than non-Hispanics to choose full-service supermarkets while White participants were more likely to travel further than non-Whites. This study demonstrates the value of explicitly spatial discrete choice models and provides evidence of national trends consistent with previous smaller, local studies. PMID:28953221

  6. Simulation study to determine the impact of different design features on design efficiency in discrete choice experiments.

    PubMed

    Vanniyasingam, Thuva; Cunningham, Charles E; Foster, Gary; Thabane, Lehana

    2016-07-19

    Discrete choice experiments (DCEs) are routinely used to elicit patient preferences to improve health outcomes and healthcare services. While many fractional factorial designs can be created, some are more statistically optimal than others. The objective of this simulation study was to investigate how varying the number of (1) attributes, (2) levels within attributes, (3) alternatives and (4) choice tasks per survey will improve or compromise the statistical efficiency of an experimental design. A total of 3204 DCE designs were created to assess how relative design efficiency (d-efficiency) is influenced by varying the number of choice tasks (2-20), alternatives (2-5), attributes (2-20) and attribute levels (2-5) of a design. Choice tasks were created by randomly allocating attribute and attribute level combinations into alternatives. Relative d-efficiency was used to measure the optimality of each DCE design. DCE design complexity influenced statistical efficiency. Across all designs, relative d-efficiency decreased as the number of attributes and attribute levels increased. It increased for designs with more alternatives. Lastly, relative d-efficiency converges as the number of choice tasks increases, where convergence may not be at 100% statistical optimality. Achieving 100% d-efficiency is heavily dependent on the number of attributes, attribute levels, choice tasks and alternatives. Further exploration of overlaps and block sizes are needed. This study's results are widely applicable for researchers interested in creating optimal DCE designs to elicit individual preferences on health services, programmes, policies and products. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  7. 34 CFR 200.48 - Funding for choice-related transportation and supplemental educational services.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Agencies Lea and School Improvement § 200.48 Funding for choice-related transportation and supplemental... all requests for supplemental educational services under § 200.45; or (iii) Pay for both paragraph (a... school choice options under § 200.44, in the amounts required under paragraph (a)(2) of this section; and...

  8. 34 CFR 200.48 - Funding for choice-related transportation and supplemental educational services.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Agencies Lea and School Improvement § 200.48 Funding for choice-related transportation and supplemental... all requests for supplemental educational services under § 200.45; or (iii) Pay for both paragraph (a... school choice options under § 200.44, in the amounts required under paragraph (a)(2) of this section; and...

  9. Designing a Text Messaging Intervention to Improve Physical Activity Behavior Among Low-Income Latino Patients With Diabetes: A Discrete-Choice Experiment, Los Angeles, 2014-2015.

    PubMed

    Ramirez, Magaly; Wu, Shinyi; Beale, Elizabeth

    2016-12-22

    Automated text messaging can deliver self-management education to activate self-care behaviors among people with diabetes. We demonstrated how a discrete-choice experiment was used to determine the features of a text-messaging intervention that are important to urban, low-income Latino patients with diabetes and that could support improvement in their physical activity behavior. In a discrete-choice experiment from December 2014 through August 2015 we conducted a survey to elicit information on patient preferences for 5 features of a text-messaging intervention. We described 2 hypothetical interventions and in 7 pairwise comparisons asked respondents to indicate which they preferred. Respondents (n = 125) were recruited in person from a diabetes management program of a safety-net ambulatory care clinic in Los Angeles; clinicians referred patients to the research assistant after routine clinic visits. Data were analyzed by using conditional logistic regression. We found 2 intervention features that were considered by the survey respondents to be important: 1) the frequency of text messaging and 2) physical activity behavior-change education (the former being more important than the latter). Physical activity goal setting, feedback on physical activity performance, and social support were not significantly important. A discrete-choice experiment is a feasible way to elicit information on patient preferences for a text-messaging intervention designed to support behavior change. However, discrepancies may exist between patients' stated preferences and their actual behavior. Future research should validate and expand our findings.

  10. Contraceptive preferences and use among auto artisanal workers in the informal sector of Kumasi, Ghana: a discrete choice experiment.

    PubMed

    Agyei-Baffour, Peter; Boahemaa, Mary Yaa; Addy, Ernestine A

    2015-04-12

    Contraceptive uptake in Ghana, especially in the Ashanti region remains low. This may be partly due to products' characteristics and choice which are influenced by attribute utility trade-offs by consumers in determining which method offers the optimal combinations, given the needs and desires of the individuals making the choice. The study sought to determine how specific attributes of contraceptives influence artisanal auto mechanics' stated preferences for a hypothetical contraceptive use in the Tafo-Suame industrial area of Kumasi, Ghana. A discrete choice experiment was conducted with artisanal auto mechanics in the study area from May to September 2011. Based on the summary of the attributes from the focus group discussion and in-depth interviews preceded administration of structured questionnaire, a discrete choice experiment (DCE) was created. The attributes used were; side effects, reversibility, ease of use, ability to prevent both pregnancy and sexually transmitted infection (STI's), price and privacy in acquiring and attractiveness of the method. A total of 340 consented respondents aged 15 to 49 years participated in the study. Data were entered in Access and Sawtooth software SSI Web CAPi module and then exported to Stata for analysis. The study showed a universal (99.4%) knowledge on contraception, ever used 87% and currently using a method, 58%. The study revealed that methods' reversibility (β = 21.74; 95% CI: 20.17, 23.3), minimal allergic reaction (β = 13.93; 95% CI: 12.8, 15.05) and no effect on blood pressure (β = 12.71; 95% CI: 11.62, 13.79), were strongly associated with contraceptive preference and use. While contraceptives' ability to prevent "only pregnancy", (β = -15.13: 95% CI: -16.2, -14.02; "only STI's") (β = -11.65; 95% CI: -11.84, -11.46); and interrupt during sexual activity (β = -4.26; 95% CI: -5.19, -3.34), had large negative influence on contraceptive preference and use. The study has documented the

  11. Deleting 'irrational' responses from discrete choice experiments: a case of investigating or imposing preferences?

    PubMed

    Lancsar, Emily; Louviere, Jordan

    2006-08-01

    Investigation of the 'rationality' of responses to discrete choice experiments (DCEs) has been a theme of research in health economics. Responses have been deleted from DCEs where they have been deemed by researchers to (a) be 'irrational', defined by such studies as failing tests for non-satiation, or (b) represent lexicographic preferences. This paper outlines a number of reasons why deleting responses from DCEs may be inappropriate after first reviewing the theory underpinning rationality, highlighting that the importance placed on rationality depends on the approach to consumer theory to which one ascribes. The aim of this paper is not to suggest that all preferences elicited via DCEs are rational. Instead, it is to suggest a number of reasons why it may not be the case that all preferences labelled as 'irrational' are indeed so. Hence, deleting responses may result in the removal of valid preferences; induce sample selection bias; and reduce the statistical efficiency and power of the estimated choice models. Further, evidence suggests random utility theory may be able to cope with such preferences. Finally, we discuss a number of implications for the design, implementation and interpretation of DCEs and recommend caution regarding the deletion of preferences from stated preference experiments. Copyright 2006 John Wiley & Sons, Ltd.

  12. Employment preferences of public sector nurses in Malawi: results from a discrete choice experiment.

    PubMed

    Mangham, Lindsay J; Hanson, Kara

    2008-12-01

    To understand the employment preferences of Malawian public sector registered nurses, and to ascertain whether salary increases significantly affect how nurses regard their employment. A discrete choice experiment was used to assess the significance of six job attributes on nurses' preferences over pairs of job descriptions: net monthly pay, provision of government housing, opportunities to upgrade their qualifications, typical workload, availability of resources and place of work. A multivariate model was used to estimate the extent to which nurses were willing to trade between their monetary benefits, non-monetary benefits, and working conditions, and to determine the relative importance of the job attributes. Most nurses were willing to trade among attributes, and very few appeared to have preferences that were dominated by a single job attribute. All attributes had a statistically significant influence on nurses' preferences, and further analysis showed the rate at which they were willing to forego pay increases for other improvements in their employment conditions. Opportunities to upgrade professional qualifications, government housing and the increases in net monthly pay had the greatest impact on nurses' employment choices. Salary enhancement can improve the motivation and retention of nurses, as well as improvements of employment conditions, which support existing efforts to address the health worker shortage.

  13. Eliciting preferences for social health insurance in Ethiopia: a discrete choice experiment.

    PubMed

    Obse, Amarech; Ryan, Mandy; Heidenreich, Sebastian; Normand, Charles; Hailemariam, Damen

    2016-12-01

    As low-income countries are initiating health insurance schemes, Ethiopia is also planning to move away from out-of-pocket private payments to health insurance. The success of such a policy depends on understanding and predicting preferences of potential enrolees. This is because a scarce health care budget forces providers and consumers to make trade-offs between potential benefits within a health insurance. An assessment of preferences of potential enrolees can therefore add important information to optimal resource allocation in the design of health insurance. We used a discrete choice experiment to elicit preferences for social health insurance (SHI) among formal sector employees in Ethiopia. Respondents were presented with 18 binary hypothetical choices of SHI. Each insurance package was described by eight policy relevant attributes: premium, enrolment, exclusions, providers and coverage of inpatient services, outpatient services, drugs and tests. A mixed logit model was estimated to determine respondents' willingness to pay (WTP) for the different health insurance attributes. We also predicted probabilities of uptake for alternative SHI scenarios. Health insurance packages with 'no exclusions', 'public and private' providers, low rate of premium and full coverage of tests and drugs were highly valued and had greatest impact on the choices . Other things being equal, respondents were willing to contribute 1.52% (95% confidence interval (CI): 0.71, 2.32) of their salary to a SHI package with no service exclusions having public and private service providers. This is substantially lower than the proposed 3% premium in the draft SHI strategy. For the typical SHI package proposed by the SHI strategy at the time, the uptake probability was predicted to be 29% (95% CI: 0.25, 0.33). The low uptake probability and WTP for the proposed SHI package suggests considering preferences of the potential enrolees' in revisions of the draft SHI strategy for introduction of

  14. Preferences for a third-trimester ultrasound scan in a low-risk obstetric population: a discrete choice experiment.

    PubMed

    Lynn, Fiona A; Crealey, Grainne E; Alderdice, Fiona A; McElnay, James C

    2015-10-01

    Establish maternal preferences for a third-trimester ultrasound scan in a healthy, low-risk pregnant population. Cross-sectional study incorporating a discrete choice experiment. A large, urban maternity hospital in Northern Ireland. One hundred and forty-six women in their second trimester of pregnancy. A discrete choice experiment was designed to elicit preferences for four attributes of a third-trimester ultrasound scan: health-care professional conducting the scan, detection rate for abnormal foetal growth, provision of non-medical information, cost. Additional data collected included age, marital status, socio-economic status, obstetric history, pregnancy-specific stress levels, perceived health and whether pregnancy was planned. Analysis was undertaken using a mixed logit model with interaction effects. Women's preferences for, and trade-offs between, the attributes of a hypothetical scan and indirect willingness-to-pay estimates. Women had significant positive preference for higher rate of detection, lower cost and provision of non-medical information, with no significant value placed on scan operator. Interaction effects revealed subgroups that valued the scan most: women experiencing their first pregnancy, women reporting higher levels of stress, an adverse obstetric history and older women. Women were able to trade on aspects of care and place relative importance on clinical, non-clinical outcomes and processes of service delivery, thus highlighting the potential of using health utilities in the development of services from a clinical, economic and social perspective. Specifically, maternal preferences exhibited provide valuable information for designing a randomized trial of effectiveness and insight for clinical and policy decision makers to inform woman-centred care. © 2013 Blackwell Publishing Ltd.

  15. Preferences for Early Intervention Mental Health Services: A Discrete-Choice Conjoint Experiment.

    PubMed

    Becker, Mackenzie P E; Christensen, Bruce K; Cunningham, Charles E; Furimsky, Ivana; Rimas, Heather; Wilson, Fiona; Jeffs, Lisa; Bieling, Peter J; Madsen, Victoria; Chen, Yvonne Y S; Mielko, Stephanie; Zipursky, Robert B

    2016-02-01

    Early intervention services (EISs) for mental illness may improve outcomes, although treatment engagement is often a problem. Incorporating patients' preferences in the design of interventions improves engagement. A discrete-choice conjoint experiment was conducted in Canada to identify EIS attributes that encourage treatment initiation. Sixteen four-level attributes were formalized into a conjoint survey, completed by patients, family members, and mental health professionals (N=562). Participants were asked which EIS option people with mental illness would contact. Latent-class analysis identified respondent classes characterized by shared preferences. Randomized first-choice simulations predicted which hypothetical options, based on attributes, would result in maximum utilization. Participants in the conventional-service class (N=241, 43%) predicted that individuals would contact traditional services (for example, hospital location and staffed by psychologists or psychiatrists). Membership was associated with being a patient or family member and being male. Participants in the convenient-service class (N=321, 57%) predicted that people would contact services promoting easy access (for example, self-referral and access from home). Membership was associated with being a professional. Both classes predicted that people would contact services that included short wait times, direct contact with professionals, patient autonomy, and psychological treatment information. The convenient-service class predicted that people would use an e-health model, whereas the conventional-service class predicted that people would use a primary care or clinic-hospital model. Provision of a range of services may maximize EIS use. Professionals may be more apt to adopt EISs in line with their beliefs regarding patient preferences. Considering several perspectives is important for service design.

  16. Lost in the crowd? Using eye-tracking to investigate the effect of complexity on attribute non-attendance in discrete choice experiments.

    PubMed

    Spinks, Jean; Mortimer, Duncan

    2016-02-03

    The provision of additional information is often assumed to improve consumption decisions, allowing consumers to more accurately weigh the costs and benefits of alternatives. However, increasing the complexity of decision problems may prompt changes in information processing. This is particularly relevant for experimental methods such as discrete choice experiments (DCEs) where the researcher can manipulate the complexity of the decision problem. The primary aims of this study are (i) to test whether consumers actually process additional information in an already complex decision problem, and (ii) consider the implications of any such 'complexity-driven' changes in information processing for design and analysis of DCEs. A discrete choice experiment (DCE) is used to simulate a complex decision problem; here, the choice between complementary and conventional medicine for different health conditions. Eye-tracking technology is used to capture the number of times and the duration that a participant looks at any part of a computer screen during completion of DCE choice sets. From this we can analyse what has become known in the DCE literature as 'attribute non-attendance' (ANA). Using data from 32 participants, we model the likelihood of ANA as a function of choice set complexity and respondent characteristics using fixed and random effects models to account for repeated choice set completion. We also model whether participants are consistent with regard to which characteristics (attributes) they consider across choice sets. We find that complexity is the strongest predictor of ANA when other possible influences, such as time pressure, ordering effects, survey specific effects and socio-demographic variables (including proxies for prior experience with the decision problem) are considered. We also find that most participants do not apply a consistent information processing strategy across choice sets. Eye-tracking technology shows promise as a way of obtaining

  17. Discrete element modelling of bedload transport

    NASA Astrophysics Data System (ADS)

    Loyer, A.; Frey, P.

    2011-12-01

    Discrete element modelling (DEM) has been widely used in solid mechanics and in granular physics. In this type of modelling, each individual particle is taken into account and intergranular interactions are modelled with simple laws (e.g. Coulomb friction). Gravity and contact forces permit to solve the dynamical behaviour of the system. DEM is interesting to model configurations and access to parameters not directly available in laboratory experimentation, hence the term "numerical experimentations" sometimes used to describe DEM. DEM was used to model bedload transport experiments performed at the particle scale with spherical glass beads in a steep and narrow flume. Bedload is the larger material that is transported on the bed on stream channels. It has a great geomorphic impact. Physical processes ruling bedload transport and more generally coarse-particle/fluid systems are poorly known, arguably because granular interactions have been somewhat neglected. An existing DEM code (PFC3D) already computing granular interactions was used. We implemented basic hydrodynamic forces to model the fluid interactions (buoyancy, drag, lift). The idea was to use the minimum number of ingredients to match the experimental results. Experiments were performed with one-size and two-size mixtures of coarse spherical glass beads entrained by a shallow turbulent and supercritical water flow down a steep channel with a mobile bed. The particle diameters were 4 and 6mm, the channel width 6.5mm (about the same width as the coarser particles) and the channel inclination was typically 10%. The water flow rate and the particle rate were kept constant at the upstream entrance and adjusted to obtain bedload transport equilibrium. Flows were filmed from the side by a high-speed camera. Using image processing algorithms made it possible to determine the position, velocity and trajectory of both smaller and coarser particles. Modelled and experimental particle velocity and concentration depth

  18. Treatment preferences of originator versus biosimilar drugs in Crohn's disease; discrete choice experiment among gastroenterologists.

    PubMed

    Baji, Petra; Gulácsi, László; Lovász, Barbara D; Golovics, Petra A; Brodszky, Valentin; Péntek, Márta; Rencz, Fanni; Lakatos, Péter L

    2016-01-01

    To explore preferences of gastroenterologists for biosimilar drugs in Crohn's disease. Discrete choice experiment was carried out involving 51 Hungarian gastroenterologists in May 2014. The following attributes were used to describe hypothetical choice sets: 1) type of the treatment (biosimilar/originator), 2) severity of disease, 3) availability of continuous medicine supply, 4) frequency of the efficacy check-ups. Multinomial logit model was used to differentiate between three attitude types: 1) always opting for the originator, 2) willing to consider biosimilar for biological-naïve patients only, 3) willing to consider biosimilar treatment for both types of patients. Conditional logit model was used to estimate the probabilities of choosing a given profile. Men, senior consultants, working in inflammatory bowel disease center and treating more patients were more likely willing to consider biosimilar for biological-naïve patients only. Treatment type (originator/biosimilar) was the most important determinant of choice for patients already treated with biologicals, and the availability of continuous medicine supply in case of biological-naïve patients. The probabilities of choosing the biosimilar with all the benefits offered over the originator under current reimbursement conditions are 89% versus 11% for new patients, and 44% versus 56% for patients already treated with biological. For gastroenterologist, the continuous medical supply would be one of the major benefits of biosimilars. However, benefits offered in the scenarios do not compensate for the change from the originator to the biosimilar treatment of patients already treated with biologicals.

  19. End-of-life healthcare expenditure: Testing economic explanations using a discrete choice experiment.

    PubMed

    Fischer, Barbara; Telser, Harry; Zweifel, Peter

    2018-06-07

    Healthcare expenditure (HCE) spent during an individual's last year of life accounts for a high share of lifetime HCE. This finding is puzzling because an investment in health is unlikely to have a sufficiently long payback period. However, Becker et al. (2007) and Philipson et al. (2010) have advanced a theory designed to explain high willingness to pay (WTP) for an extension of life close to its end. Their testable implications are complemented by the concept of 'pain of risk bearing' introduced by Eeckhoudt and Schlesinger (2006). They are tested using a discrete choice experiment performed in 2014, involving 1,529 Swiss adults. An individual setting where the price attribute is substantial out-of-pocket payment for a novel drug for treatment of terminal cancer is distinguished from a societal one, where it is an increase in contributions to social health insurance. Most of the economic predictions receive empirical support. Copyright © 2018. Published by Elsevier B.V.

  20. Education and patient preferences for treating type 2 diabetes: a stratified discrete-choice experiment

    PubMed Central

    Janssen, Ellen M; Longo, Daniel R; Bardsley, Joan K; Bridges, John FP

    2017-01-01

    Purpose Diabetes is a chronic condition that is more prevalent among people with lower educational attainment. This study assessed the treatment preferences of patients with type 2 diabetes by educational attainment. Methods Patients with type 2 diabetes were recruited from a national online panel in the US. Treatment preferences were assessed using a discrete-choice experiment. Participants completed 16 choice tasks in which they compared pairs of treatment profiles composed of six attributes: A1c decrease, stable blood glucose, low blood glucose, nausea, treatment burden, and out-of-pocket cost. Choice models and willingness-to-pay (WTP) estimates were estimated using a conditional logit model and were stratified by educational status. Results A total of 231 participants with a high school diploma or less education, 156 participants with some college education, and 165 participants with a college degree or more completed the survey. Participants with a college degree or more education were willing to pay more for A1c decreases ($58.84, standard error [SE]: 10.6) than participants who had completed some college ($28.47, SE: 5.53) or high school or less ($17.56, SE: 3.55) (p≤0.01). People with a college education were willing to pay more than people with high school or less to avoid nausea, low blood glucose events during the day/night, or two pills per day. Conclusion WTP for aspects of diabetes medication differed for people with a college education or more and a high school education or less. Advanced statistical methods might overcome limitations of stratification and advance understanding of preference heterogeneity for use in patient-centered benefit–risk assessments and personalized care approaches. PMID:29070940

  1. Education and patient preferences for treating type 2 diabetes: a stratified discrete-choice experiment.

    PubMed

    Janssen, Ellen M; Longo, Daniel R; Bardsley, Joan K; Bridges, John Fp

    2017-01-01

    Diabetes is a chronic condition that is more prevalent among people with lower educational attainment. This study assessed the treatment preferences of patients with type 2 diabetes by educational attainment. Patients with type 2 diabetes were recruited from a national online panel in the US. Treatment preferences were assessed using a discrete-choice experiment. Participants completed 16 choice tasks in which they compared pairs of treatment profiles composed of six attributes: A1c decrease, stable blood glucose, low blood glucose, nausea, treatment burden, and out-of-pocket cost. Choice models and willingness-to-pay (WTP) estimates were estimated using a conditional logit model and were stratified by educational status. A total of 231 participants with a high school diploma or less education, 156 participants with some college education, and 165 participants with a college degree or more completed the survey. Participants with a college degree or more education were willing to pay more for A1c decreases ($58.84, standard error [SE]: 10.6) than participants who had completed some college ($28.47, SE: 5.53) or high school or less ($17.56, SE: 3.55) ( p ≤0.01). People with a college education were willing to pay more than people with high school or less to avoid nausea, low blood glucose events during the day/night, or two pills per day. WTP for aspects of diabetes medication differed for people with a college education or more and a high school education or less. Advanced statistical methods might overcome limitations of stratification and advance understanding of preference heterogeneity for use in patient-centered benefit-risk assessments and personalized care approaches.

  2. Women's Benefits and Harms Trade-Offs in Breast Cancer Screening: Results from a Discrete-Choice Experiment.

    PubMed

    Sicsic, Jonathan; Pelletier-Fleury, Nathalie; Moumjid, Nora

    2018-01-01

    Over the past decade, the benefits and harms balance of breast cancer (BC) screening has been widely debated. To elicit women's trade-offs between the benefits and harms of BC screening and to analyze the main determinants of these trade-offs. A discrete-choice experiment with seven attributes depicting BC screening programs including varying levels of BC mortality, overdiagnosis, and false-positive result was used. Eight hundred twelve women aged 40 to 74 years with no personal history of BC recruited by a survey institute and representative of the French general population (age, socioeconomic level, and geographical location) completed the discrete-choice experiment. Preference heterogeneity was investigated using generalized multinomial logit models from which individual trade-offs were derived, and their main determinants were assessed using generalized linear models. Screening acceptance rates under various benefits and harms ratios were simulated on the basis of the distribution of individual preferences. The women would be willing to accept on average 14.1 overdiagnosis cases (median = 9.6) and 47.8 false-positive results (median = 27.2) to avoid one BC-related death. After accounting for preference heterogeneity, less than 50% of women would be willing to accept 10 overdiagnosis cases for one BC-related death avoided. Screening acceptance rates were higher among women with higher socioeconomic level and lower among women with poor health. Women are sensitive to both the benefits and the harms of BC screening and their preferences are highly heterogeneous. Our study provides useful results for public health authorities and clinicians willing to improve their recommendations of BC screening on the basis of women's preferences. Copyright © 2018 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  3. Impact of Retirement Choices of Early Career Marines: A Choice Analysis Model

    DTIC Science & Technology

    2013-03-01

    CHOICES OF EARLY CAREER MARINES: A CHOICE ANALYSIS MODEL by André G. La Taste Aaron Masaitis March 2013 Thesis Advisor: Michael Dixon... ANALYSIS MODEL 5. FUNDING NUMBERS 6. AUTHOR(S) André G. La Taste, Aaron Masaitis 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Naval Postgraduate...system. The research will be conducted using a discrete choice analysis methodology that is often used to differentiate factors that lead to

  4. A flexible nonlinear diffusion acceleration method for the S N transport equations discretized with discontinuous finite elements

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Schunert, Sebastian; Wang, Yaqi; Gleicher, Frederick

    This paper presents a flexible nonlinear diffusion acceleration (NDA) method that discretizes both the S N transport equation and the diffusion equation using the discontinuous finite element method (DFEM). The method is flexible in that the diffusion equation can be discretized on a coarser mesh with the only restriction that it is nested within the transport mesh and the FEM shape function orders of the two equations can be different. The consistency of the transport and diffusion solutions at convergence is defined by using a projection operator mapping the transport into the diffusion FEM space. The diffusion weak form ismore » based on the modified incomplete interior penalty (MIP) diffusion DFEM discretization that is extended by volumetric drift, interior face, and boundary closure terms. In contrast to commonly used coarse mesh finite difference (CMFD) methods, the presented NDA method uses a full FEM discretized diffusion equation for acceleration. Suitable projection and prolongation operators arise naturally from the FEM framework. Via Fourier analysis and numerical experiments for a one-group, fixed source problem the following properties of the NDA method are established for structured quadrilateral meshes: (1) the presented method is unconditionally stable and effective in the presence of mild material heterogeneities if the same mesh and identical shape functions either of the bilinear or biquadratic type are used, (2) the NDA method remains unconditionally stable in the presence of strong heterogeneities, (3) the NDA method with bilinear elements extends the range of effectiveness and stability by a factor of two when compared to CMFD if a coarser diffusion mesh is selected. In addition, the method is tested for solving the C5G7 multigroup, eigenvalue problem using coarse and fine mesh acceleration. Finally, while NDA does not offer an advantage over CMFD for fine mesh acceleration, it reduces the iteration count required for convergence by almost

  5. A flexible nonlinear diffusion acceleration method for the S N transport equations discretized with discontinuous finite elements

    DOE PAGES

    Schunert, Sebastian; Wang, Yaqi; Gleicher, Frederick; ...

    2017-02-21

    This paper presents a flexible nonlinear diffusion acceleration (NDA) method that discretizes both the S N transport equation and the diffusion equation using the discontinuous finite element method (DFEM). The method is flexible in that the diffusion equation can be discretized on a coarser mesh with the only restriction that it is nested within the transport mesh and the FEM shape function orders of the two equations can be different. The consistency of the transport and diffusion solutions at convergence is defined by using a projection operator mapping the transport into the diffusion FEM space. The diffusion weak form ismore » based on the modified incomplete interior penalty (MIP) diffusion DFEM discretization that is extended by volumetric drift, interior face, and boundary closure terms. In contrast to commonly used coarse mesh finite difference (CMFD) methods, the presented NDA method uses a full FEM discretized diffusion equation for acceleration. Suitable projection and prolongation operators arise naturally from the FEM framework. Via Fourier analysis and numerical experiments for a one-group, fixed source problem the following properties of the NDA method are established for structured quadrilateral meshes: (1) the presented method is unconditionally stable and effective in the presence of mild material heterogeneities if the same mesh and identical shape functions either of the bilinear or biquadratic type are used, (2) the NDA method remains unconditionally stable in the presence of strong heterogeneities, (3) the NDA method with bilinear elements extends the range of effectiveness and stability by a factor of two when compared to CMFD if a coarser diffusion mesh is selected. In addition, the method is tested for solving the C5G7 multigroup, eigenvalue problem using coarse and fine mesh acceleration. Finally, while NDA does not offer an advantage over CMFD for fine mesh acceleration, it reduces the iteration count required for convergence by almost

  6. Using a discrete choice experiment to value the QLU-C10D: feasibility and sensitivity to presentation format.

    PubMed

    Norman, R; Viney, R; Aaronson, N K; Brazier, J E; Cella, D; Costa, D S J; Fayers, P M; Kemmler, G; Peacock, S; Pickard, A S; Rowen, D; Street, D J; Velikova, G; Young, T A; King, M T

    2016-03-01

    To assess the feasibility of using a discrete choice experiment (DCE) to value health states within the QLU-C10D, a utility instrument derived from the QLQ-C30, and to assess clarity, difficulty, and respondent preference between two presentation formats. We ran a DCE valuation task in an online panel (N = 430). Respondents answered 16 choice pairs; in half of these, differences between dimensions were highlighted, and in the remainder, common dimensions were described in text and differing attributes were tabulated. To simplify the cognitive task, only four of the QLU-C10D's ten dimensions differed per choice set. We assessed difficulty and clarity of the valuation task with Likert-type scales, and respondents were asked which format they preferred. We analysed the DCE data by format with a conditional logit model and used Chi-squared tests to compare other responses by format. Semi-structured telephone interviews (N = 8) explored respondents' cognitive approaches to the valuation task. Four hundred and forty-nine individuals were recruited, 430 completed at least one choice set, and 422/449 (94 %) completed all 16 choice sets. Interviews revealed that respondents found ten domains difficult but manageable, many adopting simplifying heuristics. Results for clarity and difficulty were identical between formats, but the "highlight" format was preferred by 68 % of respondents. Conditional logit parameter estimates were monotonic within domains, suggesting respondents were able to complete the DCE sensibly, yielding valid results. A DCE valuation task in which only four of the QLU-C10D's ten dimensions differed in any choice set is feasible for deriving utility weights for the QLU-C10D.

  7. Women’s Preferences for Treatment of Perinatal Depression and Anxiety: A Discrete Choice Experiment

    PubMed Central

    Ride, Jemimah; Lancsar, Emily

    2016-01-01

    Perinatal depression and anxiety (PNDA) are an international healthcare priority, associated with significant short- and long-term problems for women, their children and families. Effective treatment is available but uptake is suboptimal: some women go untreated whilst others choose treatments without strong evidence of efficacy. Better understanding of women’s preferences for treatment is needed to facilitate uptake of effective treatment. To address this issue, a discrete choice experiment (DCE) was administered to 217 pregnant or postnatal women in Australia, who were recruited through an online research company and had similar sociodemographic characteristics to Australian data for perinatal women. The DCE investigated preferences regarding cost, treatment type, availability of childcare, modality and efficacy. Data were analysed using logit-based models accounting for preference and scale heterogeneity. Predicted probability analysis was used to explore relative attribute importance and policy change scenarios, including how these differed by women’s sociodemographic characteristics. Cost and treatment type had the greatest impact on choice, such that a policy of subsidising effective treatments was predicted to double their uptake compared with the base case. There were differences in predicted uptake associated with certain sociodemographic characteristics: for example, women with higher educational attainment were more likely to choose effective treatment. The findings suggest policy directions for decision makers whose goal is to reduce the burden of PNDA on women, their children and families. PMID:27258096

  8. dfnWorks: A discrete fracture network framework for modeling subsurface flow and transport

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hyman, Jeffrey D.; Karra, Satish; Makedonska, Nataliia

    DFNWORKS is a parallelized computational suite to generate three-dimensional discrete fracture networks (DFN) and simulate flow and transport. Developed at Los Alamos National Laboratory over the past five years, it has been used to study flow and transport in fractured media at scales ranging from millimeters to kilometers. The networks are created and meshed using DFNGEN, which combines FRAM (the feature rejection algorithm for meshing) methodology to stochastically generate three-dimensional DFNs with the LaGriT meshing toolbox to create a high-quality computational mesh representation. The representation produces a conforming Delaunay triangulation suitable for high performance computing finite volume solvers in anmore » intrinsically parallel fashion. Flow through the network is simulated in dfnFlow, which utilizes the massively parallel subsurface flow and reactive transport finite volume code PFLOTRAN. A Lagrangian approach to simulating transport through the DFN is adopted within DFNTRANS to determine pathlines and solute transport through the DFN. Example applications of this suite in the areas of nuclear waste repository science, hydraulic fracturing and CO 2 sequestration are also included.« less

  9. dfnWorks: A discrete fracture network framework for modeling subsurface flow and transport

    DOE PAGES

    Hyman, Jeffrey D.; Karra, Satish; Makedonska, Nataliia; ...

    2015-11-01

    DFNWORKS is a parallelized computational suite to generate three-dimensional discrete fracture networks (DFN) and simulate flow and transport. Developed at Los Alamos National Laboratory over the past five years, it has been used to study flow and transport in fractured media at scales ranging from millimeters to kilometers. The networks are created and meshed using DFNGEN, which combines FRAM (the feature rejection algorithm for meshing) methodology to stochastically generate three-dimensional DFNs with the LaGriT meshing toolbox to create a high-quality computational mesh representation. The representation produces a conforming Delaunay triangulation suitable for high performance computing finite volume solvers in anmore » intrinsically parallel fashion. Flow through the network is simulated in dfnFlow, which utilizes the massively parallel subsurface flow and reactive transport finite volume code PFLOTRAN. A Lagrangian approach to simulating transport through the DFN is adopted within DFNTRANS to determine pathlines and solute transport through the DFN. Example applications of this suite in the areas of nuclear waste repository science, hydraulic fracturing and CO 2 sequestration are also included.« less

  10. Forecasting the impact of transport improvements on commuting and residential choice

    NASA Astrophysics Data System (ADS)

    Elhorst, J. Paul; Oosterhaven, Jan

    2006-03-01

    This paper develops a probabilistic, competing-destinations, assignment model that predicts changes in the spatial pattern of the working population as a result of transport improvements. The choice of residence is explained by a new non-parametric model, which represents an alternative to the popular multinominal logit model. Travel times between zones are approximated by a normal distribution function with different mean and variance for each pair of zones, whereas previous models only use average travel times. The model’s forecast error of the spatial distribution of the Dutch working population is 7% when tested on 1998 base-year data. To incorporate endogenous changes in its causal variables, an almost ideal demand system is estimated to explain the choice of transport mode, and a new economic geography inter-industry model (RAEM) is estimated to explain the spatial distribution of employment. In the application, the model is used to forecast the impact of six mutually exclusive Dutch core-periphery railway proposals in the projection year 2020.

  11. Modeling the Mental Health Practice Change Preferences of Educators: A Discrete-Choice Conjoint Experiment.

    PubMed

    Cunningham, Charles E; Barwick, Melanie; Short, Kathy; Chen, Yvonne; Rimas, Heather; Ratcliffe, Jenna; Mielko, Stephanie

    2014-01-01

    Schools are sometimes slow to adopt evidence-based strategies for improving the mental health outcomes of students. This study used a discrete-choice conjoint experiment to model factors influencing the decision of educators to adopt strategies for improving children's mental health outcomes. A sample of 1,010 educators made choices between hypothetical mental health practice change strategies composed by systematically varying the four levels of 16 practice change attributes. Latent class analysis yielded two segments with different practice change preferences. Both segments preferred small-group workshops, conducted by engaging experts, teaching skills applicable to all students. Participants expressed little interest in Internet options. The support of colleagues, administrators, and unions exerted a strong influence on the practice change choices of both segments. The Change Ready segment, 77.1 % of the sample, was more intent on adopting new strategies to improve the mental health of students. They preferred that schools, rather than the provincial ministry of education, make practice change decisions, coaching was provided to all participants, and participants received post-training follow-up sessions. The Demand Sensitive segment (22.9 %) was less intent on practice change. They preferred that individual teachers make practice change decisions, recommended discretionary coaching, and chose no post-training follow-up support. This study emphasizes the complex social, organizational, and policy context within which educators make practice change decisions. Efforts to disseminate strategies to improve the mental health outcomes of students need to be informed by the preferences of segments of educators who are sensitive to different dimensions of the practice change process. In the absence of a broad consensus of educators, administrators, and unions, potentially successful practice changes are unlikely to be adopted.

  12. Using stated preference discrete choice modelling to evaluate the introduction of varicella vaccination.

    PubMed

    Hall, Jane; Kenny, Patricia; King, Madeleine; Louviere, Jordan; Viney, Rosalie; Yeoh, Angela

    2002-07-01

    Applications of stated preference discrete choice modelling (SPDCM) in health economics have been used to estimate consumer willingness to pay and to broaden the range of consequences considered in economic evaluation. This paper demonstrates how SPDCM can be used to predict participation rates, using the case of varicella (chickenpox) vaccination. Varicella vaccination may be cost effective compared to other public health programs, but this conclusion is sensitive to the proportion of the target population immunised. A choice experiment was conducted on a sample of Australian parents to predict uptake across a range of hypothetical programs. Immunisation rates would be increased by providing immunisation at no cost, by requiring it for school entry, by increasing immunisation rates in the community and decreasing the incidence of mild and severe side effects. There were two significant interactions; price modified the effect of both support from authorities and severe side effects. Country of birth was the only significant demographic characteristic. Depending on aspects of the immunisation program, the immunisation rates of children with Australian-born parents varied from 9% to 99% while for the children with parents born outside Australia they varied from 40% to 99%. This demonstrates how SPDCM can be used to understand the levels of attributes that will induce a change in the decision to immunise, the modification of the effect of one attribute by another, and subgroups in the population. Such insights can contribute to the optimal design and targeting of health programs. Copyright 2002 John Wiley & Sons, Ltd.

  13. Functional forms and price elasticities in a discrete continuous choice model of the residential water demand

    NASA Astrophysics Data System (ADS)

    Vásquez Lavín, F. A.; Hernandez, J. I.; Ponce, R. D.; Orrego, S. A.

    2017-07-01

    During recent decades, water demand estimation has gained considerable attention from scholars. From an econometric perspective, the most used functional forms include log-log and linear specifications. Despite the advances in this field and the relevance for policymaking, little attention has been paid to the functional forms used in these estimations, and most authors have not provided justifications for their selection of functional forms. A discrete continuous choice model of the residential water demand is estimated using six functional forms (log-log, full-log, log-quadratic, semilog, linear, and Stone-Geary), and the expected consumption and price elasticity are evaluated. From a policy perspective, our results highlight the relevance of functional form selection for both the expected consumption and price elasticity.

  14. Patient versus neurologist preferences: A discrete choice experiment for antiepileptic drug therapies.

    PubMed

    Ettinger, Alan B; Carter, John A; Rajagopalan, Krithika

    2018-03-01

    This assessment was conducted to quantify and compare patient and neurologist preferences regarding antiepileptic drug (AED) attributes for treating epilepsy. Patients with epilepsy (≥18years, treated with AEDs) and neurologists were recruited from nationally representative US panels to complete an online survey that included a discrete choice experiment (DCE). Participants chose between two hypothetical AEDs, characterized by six attributes in the DCE, which included 1) level of seizure control/reduction; 2) dosing frequency, 3) diminished coordination and balance, 4) psychiatric issues, 5) diminished energy level, and 6) dietary restrictions. The Sawtooth Software Choice-Based Conjoint (CBC) System for CBC Analysis was used to estimate treatment attribute ranking and weighting. Of the 720 respondents (518 patients and 202 neurologists), both patients and neurologists ranked seizure control as the most important attribute (rank 1) and dietary restrictions as the least important attribute (rank 6). However, seizure control had a significantly greater weighting in neurologists' decision-making than among patients (45% vs 32%, p<0.005). On the other hand, patients considered the risks of psychiatric adverse effects (19% vs 15%), diminished coordination and balance (16% vs 10%), and fatigue or diminished energy (13% vs 11%) as significantly more important (p<0.05) than did neurologists. Patients and neurologists had similar preference ranking order, with seizure reduction being ranked the most important attribute. However, neurologist treatment preferences were significantly more influenced by seizure reduction while patient preferences were significantly more influenced by adverse effects that may impact their quality of life. Understanding how patient and neurologist perspectives differ should encourage dialog to communicate the potential risks and benefits of AED therapy and assist in the shared decision-making process. Copyright © 2018 Elsevier Inc. All rights

  15. Calculating Preference Weights for the Labor and Delivery Index: A Discrete Choice Experiment on Women's Birth Experiences.

    PubMed

    Gärtner, Fania R; de Bekker-Grob, Esther W; Stiggelbout, Anne M; Rijnders, Marlies E; Freeman, Liv M; Middeldorp, Johanna M; Bloemenkamp, Kitty W M; de Miranda, Esteriek; van den Akker-van Marle, M Elske

    2015-09-01

    The aim of this study was to calculate preference weights for the Labor and Delivery Index (LADY-X) to make it suitable as a utility measure for perinatal care studies. In an online discrete choice experiment, 18 pairs of hypothetical scenarios were presented to respondents, from which they had to choose a preferred option. The scenarios describe the birth experience in terms of the seven LADY-X attributes. A D-efficient discrete choice experiment design with priors based on a small sample (N = 110) was applied. Two samples were gathered, women who had recently given birth and subjects from the general population. Both samples were analyzed separately using a panel mixed logit (MMNL) model. Using the panel mixed multinomial logit (MMNL) model results and accounting for preference heterogeneity, we calculated the average preference weights for LADY-X attribute levels. These were transformed to represent a utility score between 0 and 1, with 0 representing the worst and 1 representing the best birth experience. In total, 1097 women who had recently given birth and 367 subjects from the general population participated. Greater value was placed on differences between bottom and middle attribute levels than on differences between middle and top levels. The attributes that resulted in larger utility increases than the other attributes were "feeling of safety" in the sample of women who had recently given birth and "feeling of safety" and "availability of professionals" in the general population sample. By using the derived preference weights, LADY-X has the potential to be used as a utility measure for perinatal (cost-) effectiveness studies. Copyright © 2015 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  16. The episodic random utility model unifies time trade-off and discrete choice approaches in health state valuation

    PubMed Central

    Craig, Benjamin M; Busschbach, Jan JV

    2009-01-01

    Background To present an episodic random utility model that unifies time trade-off and discrete choice approaches in health state valuation. Methods First, we introduce two alternative random utility models (RUMs) for health preferences: the episodic RUM and the more common instant RUM. For the interpretation of time trade-off (TTO) responses, we show that the episodic model implies a coefficient estimator, and the instant model implies a mean slope estimator. Secondly, we demonstrate these estimators and the differences between the estimates for 42 health states using TTO responses from the seminal Measurement and Valuation in Health (MVH) study conducted in the United Kingdom. Mean slopes are estimates with and without Dolan's transformation of worse-than-death (WTD) responses. Finally, we demonstrate an exploded probit estimator, an extension of the coefficient estimator for discrete choice data that accommodates both TTO and rank responses. Results By construction, mean slopes are less than or equal to coefficients, because slopes are fractions and, therefore, magnify downward errors in WTD responses. The Dolan transformation of WTD responses causes mean slopes to increase in similarity to coefficient estimates, yet they are not equivalent (i.e., absolute mean difference = 0.179). Unlike mean slopes, coefficient estimates demonstrate strong concordance with rank-based predictions (Lin's rho = 0.91). Combining TTO and rank responses under the exploded probit model improves the identification of health state values, decreasing the average width of confidence intervals from 0.057 to 0.041 compared to TTO only results. Conclusion The episodic RUM expands upon the theoretical framework underlying health state valuation and contributes to health econometrics by motivating the selection of coefficient and exploded probit estimators for the analysis of TTO and rank responses. In future MVH surveys, sample size requirements may be reduced through the incorporation of

  17. Order of Presentation of Dimensions Does Not Systematically Bias Utility Weights from a Discrete Choice Experiment.

    PubMed

    Norman, Richard; Kemmler, Georg; Viney, Rosalie; Pickard, A Simon; Gamper, Eva; Holzner, Bernhard; Nerich, Virginie; King, Madeleine

    2016-12-01

    Discrete choice experiments (DCEs) are increasingly used to value aspects of health. An issue with their adoption is that results may be sensitive to the order in which dimensions of health are presented in the valuation task. Findings in the literature regarding order effects are discordant at present. To quantify the magnitude of order effect of quality-of-life (QOL) dimensions within the context of a DCE designed to produce country-specific value sets for the EORTC Quality of Life Utility Measure-Core 10 dimensions (QLU-C10D), a new utility instrument derived from the widely used cancer-specific QOL questionnaire, the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30. The DCE comprised 960 choice sets, divided into 60 versions of 16 choice sets, with each respondent assigned to a version. Within each version, the order of QLU-C10D QOL dimensions was randomized, followed by life duration in the last position. The DCE was completed online by 2053 individuals in France and Germany. We analyzed the data with a series of conditional logit models, adjusted for repeated choices within respondent. We used F tests to assess order effects, correcting for multiple hypothesis testing. Each F test failed to reject the null hypothesis of no position effect: 1) all QOL order positions considered jointly; 2) last QOL position only; 3) first QOL position only. Furthermore, the order coefficients were small relative to those of the QLU-C10D QOL dimension levels. The order of presentation of QOL dimensions within a DCE designed to provide utility weights for the QLU-C10D had little effect on level coefficients of those QOL dimensions. Copyright © 2016 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  18. Patients’ preferences for GP consultation for perceived cancer risk in primary care: a discrete choice experiment

    PubMed Central

    Whitaker, Katriina L; Ghanouni, Alex; Zhou, Yin; Lyratzopoulos, Georgios; Morris, Stephen

    2017-01-01

    Background Contacting a doctor for advice when experiencing a potential cancer symptom is an important step in early diagnosis, but barriers to consultation are commonly reported. Understanding barriers to consulting in primary care within the cancer context provides opportunities to improve earlier diagnosis of cancer Aim To investigate patients’ GP consultation preferences when presented with a potential cancer symptom, and to describe whether these preferences are mediated by variable levels of cancer risk. Design and setting A UK-wide online survey of adults ≥50 years old, using quota sampling to reflect general population characteristics. Method A discrete choice experiment examined participants’ preferences for primary care consultation for three cancer symptom scenarios: risk level not mentioned, risk designated as ‘low’, or risk designated as ‘high’. Scenarios based on length of consultation, time to getting an appointment, convenience, choice of GP, and GP listening skills were presented in a self-completed online questionnaire. Results A total of 9616 observations were obtained from 601 participants. Participants expressed preferences for doctors with better listening skills, the ability to see a GP of their choice, and shorter waiting times. These findings were the same across risk conditions and demographic groups. Participants were willing to wait an extra 3.5 weeks for an appointment with a doctor with good/very good listening skills (versus very poor listening skills) and an extra week for an appointment with a GP of their choice (versus any GP). Conclusion Patient decisions about help seeking seem to be particularly influenced by the anticipated listening skills of doctors. Improving doctors’ communication skills may in the longer term encourage people to seek prompt medical help when they experience a cancer symptom. PMID:28483824

  19. Exacerbations of COPD: quantifying the patient's perspective using discrete choice modelling.

    PubMed

    Haughney, J; Partridge, M R; Vogelmeier, C; Larsson, T; Kessler, R; Ståhl, E; Brice, R; Löfdahl, C-G

    2005-10-01

    Patient-centred care is the current vogue in chronic obstructive pulmonary disease (COPD), but it is only recently that robust techniques have become available to determine patients' values and preferences. In this international cross-sectional study, patients' concerns and expectations regarding COPD exacerbations were explored using discrete choice modelling. A fractional factorial design was used to develop scenarios comprising a combination of levels for nine different attributes. In face-to-face interviews, patients were presented with paired scenarios and asked to choose the least preferable. Multinomial logit (with hierarchical Bayes) methods were used to estimate utilities. A total of 125 patients (82 males; mean age 66 yrs; 4.6 mean exacerbations.yr-1) were recruited. The attributes of exacerbations considered most important were impact on everyday life (20%), need for medical care (16%), number of future attacks (12%) and breathlessness (11%). The next most important attributes were speed of recovery, productive cough and social impact (all 9%), followed by sleep disturbance and impact on mood (both 7%). Importantly, analysis of utility shifts showed that patients most feared being hospitalised, housebound or bedridden. These issues were more important than symptom improvement. Strategies for the clinical management of chronic obstructive pulmonary disease should clearly address patients' concerns and focus on preventing and treating exacerbations to avoid these feared outcomes.

  20. Transport of phase space densities through tetrahedral meshes using discrete flow mapping

    NASA Astrophysics Data System (ADS)

    Bajars, Janis; Chappell, David J.; Søndergaard, Niels; Tanner, Gregor

    2017-01-01

    Discrete flow mapping was recently introduced as an efficient ray based method determining wave energy distributions in complex built up structures. Wave energy densities are transported along ray trajectories through polygonal mesh elements using a finite dimensional approximation of a ray transfer operator. In this way the method can be viewed as a smoothed ray tracing method defined over meshed surfaces. Many applications require the resolution of wave energy distributions in three-dimensional domains, such as in room acoustics, underwater acoustics and for electromagnetic cavity problems. In this work we extend discrete flow mapping to three-dimensional domains by propagating wave energy densities through tetrahedral meshes. The geometric simplicity of the tetrahedral mesh elements is utilised to efficiently compute the ray transfer operator using a mixture of analytic and spectrally accurate numerical integration. The important issue of how to choose a suitable basis approximation in phase space whilst maintaining a reasonable computational cost is addressed via low order local approximations on tetrahedral faces in the position coordinate and high order orthogonal polynomial expansions in momentum space.

  1. Are Health State Valuations from the General Public Biased? A Test of Health State Reference Dependency Using Self-assessed Health and an Efficient Discrete Choice Experiment.

    PubMed

    Jonker, Marcel F; Attema, Arthur E; Donkers, Bas; Stolk, Elly A; Versteegh, Matthijs M

    2017-12-01

    Health state valuations of patients and non-patients are not the same, whereas health state values obtained from general population samples are a weighted average of both. The latter constitutes an often-overlooked source of bias. This study investigates the resulting bias and tests for the impact of reference dependency on health state valuations using an efficient discrete choice experiment administered to a Dutch nationally representative sample of 788 respondents. A Bayesian discrete choice experiment design consisting of eight sets of 24 (matched pairwise) choice tasks was developed, with each set providing full identification of the included parameters. Mixed logit models were used to estimate health state preferences with respondents' own health included as an additional predictor. Our results indicate that respondents with impaired health worse than or equal to the health state levels under evaluation have approximately 30% smaller health state decrements. This confirms that reference dependency can be observed in general population samples and affirms the relevance of prospect theory in health state valuations. At the same time, the limited number of respondents with severe health impairments does not appear to bias social tariffs as obtained from general population samples. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  2. Characterizing outcome preferences in patients with psychotic disorders: a discrete choice conjoint experiment.

    PubMed

    Zipursky, Robert B; Cunningham, Charles E; Stewart, Bailey; Rimas, Heather; Cole, Emily; Vaz, Stephanie McDermid

    2017-07-01

    The majority of individuals with schizophrenia will achieve a remission of psychotic symptoms, but few will meet criteria for recovery. Little is known about what outcomes are important to patients. We carried out a discrete choice experiment to characterize the outcome preferences of patients with psychotic disorders. Participants (N=300) were recruited from two clinics specializing in psychotic disorders. Twelve outcomes were each defined at three levels and incorporated into a computerized survey with 15 choice tasks. Utility values and importance scores were calculated for each outcome level. Latent class analysis was carried out to determine whether participants were distributed into segments with different preferences. Multinomial logistic regression was used to identify predictors of segment membership. Latent class analysis revealed three segments of respondents. The first segment (48%), which we labeled "Achievement-focused," preferred to have a full-time job, to live independently, to be in a long-term relationship, and to have no psychotic symptoms. The second segment (29%), labeled "Stability-focused," preferred to not have a job, to live independently, and to have some ongoing psychotic symptoms. The third segment (23%), labeled "Health-focused," preferred to not have a job, to live in supervised housing, and to have no psychotic symptoms. Segment membership was predicted by education, socioeconomic status, psychotic symptom severity, and work status. This study has revealed that patients with psychotic disorders are distributed between segments with different outcome preferences. New approaches to improve outcomes for patients with psychotic disorders should be informed by a greater understanding of patient preferences and priorities. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Discrete choice experiments in pharmacy: a review of the literature.

    PubMed

    Naik-Panvelkar, Pradnya; Armour, Carol; Saini, Bandana

    2013-02-01

    Discrete choice experiments (DCEs) have been widely used to elicit patient preferences for various healthcare services and interventions. The aim of our study was to conduct an in-depth scoping review of the literature and provide a current overview of the progressive application of DCEs within the field of pharmacy. Electronic databases (MEDLINE, EMBASE, SCOPUS, ECONLIT) were searched (January 1990-August 2011) to identify published English language studies using DCEs within the pharmacy context. Data were abstracted with respect to DCE methodology and application to pharmacy. Our search identified 12 studies. The DCE methodology was utilised to elicit preferences for different aspects of pharmacy products, therapy or services. Preferences were elicited from either patients or pharmacists, with just two studies incorporating the views of both. Most reviewed studies examined preferences for process-related or provider-related aspects with a lesser focus on health outcomes. Monetary attributes were considered to be important by most patients and pharmacists in the studies reviewed. Logit, probit or multinomial logit models were most commonly employed for estimation. Our study showed that the pharmacy profession has adopted the DCE methodology consistent with the general health DCEs although the number of studies is quite limited. Future studies need to examine preferences of both patients and providers for particular products or disease-state management services. Incorporation of health outcome attributes in the design, testing for external validity and the incorporation of DCE results in economic evaluation framework to inform pharmacy policy remain important areas for future research. © 2012 The Authors. IJPP © 2012 Royal Pharmaceutical Society.

  4. Modeling the mental health service utilization decisions of university undergraduates: A discrete choice conjoint experiment.

    PubMed

    Cunningham, Charles E; Zipursky, Robert B; Christensen, Bruce K; Bieling, Peter J; Madsen, Victoria; Rimas, Heather; Mielko, Stephanie; Wilson, Fiona; Furimsky, Ivana; Jeffs, Lisa; Munn, Catharine

    2017-01-01

    We modeled design factors influencing the intent to use a university mental health service. Between November 2012 and October 2014, 909 undergraduates participated. Using a discrete choice experiment, participants chose between hypothetical campus mental health services. Latent class analysis identified three segments. A Psychological/Psychiatric Service segment (45.5%) was most likely to contact campus health services delivered by psychologists or psychiatrists. An Alternative Service segment (39.3%) preferred to talk to peer-counselors who had experienced mental health problems. A Hesitant segment (15.2%) reported greater distress but seemed less intent on seeking help. They preferred services delivered by psychologists or psychiatrists. Simulations predicted that, rather than waiting for standard counseling, the Alternative Service segment would prefer immediate access to E-Mental health. The Usual Care and Hesitant segments would wait 6 months for standard counseling. E-Mental Health options could engage students who may not wait for standard services.

  5. Eliciting preferences for waterpipe tobacco smoking using a discrete choice experiment: implications for product regulation.

    PubMed

    Salloum, Ramzi G; Maziak, Wasim; Hammond, David; Nakkash, Rima; Islam, Farahnaz; Cheng, Xi; Thrasher, James F

    2015-09-09

    Waterpipe smoking is highly prevalent among university students, and has been increasing in popularity despite mounting evidence showing it is harmful to health. The aim of this study was to measure preferences for waterpipe smoking and determine which product characteristics are most important to smokers. A large university in the Southeastern USA. Adult waterpipe smokers attending the university (N=367). Participants completed an Internet-based discrete choice experiment to reveal their preferences for, and trade-offs between, the attributes of hypothetical waterpipe smoking sessions. Participants were presented with waterpipe lounge menus, each with three fruit-flavoured options and one tobacco flavoured option, in addition to an opt out option. Nicotine content and price were provided for each choice. Participants were randomised to either receive menus with a text-only health-warning message or no message. Multinomial and nested logit models were used to estimate the impact on consumer choice of attributes and between-subject assignment of health warnings respectively. On average, participants preferred fruit-flavoured varieties to tobacco flavour. They were averse to options labelled with higher nicotine content. Females and non-smokers of cigarettes were more likely than their counterparts to prefer flavoured and nicotine-free varieties. Participants exposed to a health warning were more likely to opt out. Fruit-flavoured tobacco and lower nicotine content labels, two strategies widely used by the industry, increase the demand for waterpipe smoking among young adults. Waterpipe-specific regulation should limit the availability of flavoured waterpipe tobacco and require accurate labelling of constituents. Waterpipe-specific tobacco control regulation, along with research to inform policy, is required to curb this emerging public health threat. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence

  6. Eliciting preferences for waterpipe tobacco smoking using a discrete choice experiment: implications for product regulation

    PubMed Central

    Salloum, Ramzi G; Maziak, Wasim; Hammond, David; Nakkash, Rima; Islam, Farahnaz; Cheng, Xi; Thrasher, James F

    2015-01-01

    Objectives Waterpipe smoking is highly prevalent among university students, and has been increasing in popularity despite mounting evidence showing it is harmful to health. The aim of this study was to measure preferences for waterpipe smoking and determine which product characteristics are most important to smokers. Setting A large university in the Southeastern USA. Participants Adult waterpipe smokers attending the university (N=367). Design Participants completed an Internet-based discrete choice experiment to reveal their preferences for, and trade-offs between, the attributes of hypothetical waterpipe smoking sessions. Participants were presented with waterpipe lounge menus, each with three fruit-flavoured options and one tobacco flavoured option, in addition to an opt out option. Nicotine content and price were provided for each choice. Participants were randomised to either receive menus with a text-only health-warning message or no message. Outcome measures Multinomial and nested logit models were used to estimate the impact on consumer choice of attributes and between-subject assignment of health warnings respectively. Results On average, participants preferred fruit-flavoured varieties to tobacco flavour. They were averse to options labelled with higher nicotine content. Females and non-smokers of cigarettes were more likely than their counterparts to prefer flavoured and nicotine-free varieties. Participants exposed to a health warning were more likely to opt out. Conclusions Fruit-flavoured tobacco and lower nicotine content labels, two strategies widely used by the industry, increase the demand for waterpipe smoking among young adults. Waterpipe-specific regulation should limit the availability of flavoured waterpipe tobacco and require accurate labelling of constituents. Waterpipe-specific tobacco control regulation, along with research to inform policy, is required to curb this emerging public health threat. PMID:26353876

  7. Parameterising User Uptake in Economic Evaluations: The role of discrete choice experiments.

    PubMed

    Terris-Prestholt, Fern; Quaife, Matthew; Vickerman, Peter

    2016-02-01

    Model-based economic evaluations of new interventions have shown that user behaviour (uptake) is a critical driver of overall impact achieved. However, early economic evaluations, prior to introduction, often rely on assumed levels of uptake based on expert opinion or uptake of similar interventions. In addition to the likely uncertainty surrounding these uptake assumptions, they also do not allow for uptake to be a function of product, intervention, or user characteristics. This letter proposes using uptake projections from discrete choice experiments (DCE) to better parameterize uptake and substitution in cost-effectiveness models. A simple impact model is developed and illustrated using an example from the HIV prevention field in South Africa. Comparison between the conventional approach and the DCE-based approach shows that, in our example, DCE-based impact predictions varied by up to 50% from conventional estimates and provided far more nuanced projections. In the absence of observed uptake data and to model the effect of variations in intervention characteristics, DCE-based uptake predictions are likely to greatly improve models parameterizing uptake solely based on expert opinion. This is particularly important for global and national level decision making around introducing new and probably more expensive interventions, particularly where resources are most constrained. © 2016 The Authors. Health Economics published by John Wiley & Sons Ltd.

  8. Rationalising the 'irrational': a think aloud study of discrete choice experiment responses.

    PubMed

    Ryan, Mandy; Watson, Verity; Entwistle, Vikki

    2009-03-01

    Stated preference methods assume respondents' preferences are consistent with utility theory, but many empirical studies report evidence of preferences that violate utility theory. This evidence is often derived from quantitative tests that occur naturally within, or are added to, stated preference tasks. In this study, we use qualitative methods to explore three axioms of utility theory: completeness, monotonicity, and continuity. We take a novel approach, adopting a 'think aloud' technique to identify violations of the axioms of utility theory and to consider how well the quantitative tests incorporated within a discrete choice experiment are able to detect these. Results indicate that quantitative tests classify respondents as being 'irrational' when qualitative statements would indicate they are 'rational'. In particular, 'non-monotonic' responses can often be explained by respondents inferring additional information beyond what is presented in the task, and individuals who appear to adopt non-compensatory decision-making strategies do so because they rate particular attributes very highly (they are not attempting to simplify the task). The results also provide evidence of 'cost-based responses': respondents assumed tests with higher costs would be of higher quality. The value of including in-depth qualitative validation techniques in the development of stated preference tasks is shown.

  9. Women’s preferences for alternative financial incentive schemes for breastfeeding: A discrete choice experiment

    PubMed Central

    Anokye, Nana; de Bekker-Grob, Esther W.; Higgins, Ailish; Relton, Clare; Strong, Mark; Fox-Rushby, Julia

    2018-01-01

    Background Increasing breastfeeding rates have been associated with reductions in disease in babies and mothers as well as in related costs. ‘Nourishing Start for Health (NoSH)’, a financial incentive scheme has been proposed as a potentially effective way to increase both the number of mothers breastfeeding and duration of breastfeeding. Aims To establish women’s relative preferences for different aspects of a financial incentive scheme for breastfeeding and to identify importance of scheme characteristics on probability on participation in an incentive scheme. Methods A discrete choice experiment (DCE) obtained information on alternative specifications of the NoSH scheme designed to promote continued breastfeeding duration until at least 6 weeks after birth. Four attributes framed alternative scheme designs: value of the incentive; minimum breastfeeding duration required to receive incentive; method of verifying breastfeeding; type of incentive. Three versions of the DCE questionnaire, each containing 8 different choice sets, provided 24 choice sets for analysis. The questionnaire was mailed to 2,531 women in the South Yorkshire Cohort (SYC) aged 16–45 years in IMD quintiles 3–5. The analytic approach considered conditional and mixed effects logistic models to account for preference heterogeneity that may be associated with a variation in effects mediated by respondents’ characteristics. Results 564 women completed the questionnaire and a response rate of 22% was achieved. Most of the included attributes were found to affect utility and therefore the probability to participate in the incentive scheme. Higher rewards were preferred, although the type of incentive significantly affected women’s preferences on average. We found evidence for preference heterogeneity based on individual characteristics that mediated preferences for an incentive scheme.Conclusions Although participants’ opinion in our sample was mixed, financial incentives for

  10. Modeling organizational justice improvements in a pediatric health service : a discrete-choice conjoint experiment.

    PubMed

    Cunningham, Charles E; Kostrzewa, Linda; Rimas, Heather; Chen, Yvonne; Deal, Ken; Blatz, Susan; Bowman, Alida; Buchanan, Don H; Calvert, Randy; Jennings, Barbara

    2013-01-01

    Patients value health service teams that function effectively. Organizational justice is linked to the performance, health, and emotional adjustment of the members of these teams. We used a discrete-choice conjoint experiment to study the organizational justice improvement preferences of pediatric health service providers. Using themes from a focus group with 22 staff, we composed 14 four-level organizational justice improvement attributes. A sample of 652 staff (76 % return) completed 30 choice tasks, each presenting three hospitals defined by experimentally varying the attribute levels. Latent class analysis yielded three segments. Procedural justice attributes were more important to the Decision Sensitive segment, 50.6 % of the sample. They preferred to contribute to and understand how all decisions were made and expected management to act promptly on more staff suggestions. Interactional justice attributes were more important to the Conduct Sensitive segment (38.5 %). A universal code of respectful conduct, consequences encouraging respectful interaction, and management's response when staff disagreed with them were more important to this segment. Distributive justice attributes were more important to the Benefit Sensitive segment, 10.9 % of the sample. Simulations predicted that, while Decision Sensitive (74.9 %) participants preferred procedural justice improvements, Conduct (74.6 %) and Benefit Sensitive (50.3 %) participants preferred interactional justice improvements. Overall, 97.4 % of participants would prefer an approach combining procedural and interactional justice improvements. Efforts to create the health service environments that patients value need to be comprehensive enough to address the preferences of segments of staff who are sensitive to different dimensions of organizational justice.

  11. Preferences of overweight and obese patients for weight loss programmes: a discrete-choice experiment

    PubMed Central

    Mühlbacher, Axel; Bethge, Susanne

    2013-01-01

    Introduction Obesity is associated with increased risk of morbidity and mortality and also appears to have an adverse effect on health-related quality of life. Though advances in obesity therapy and rehabilitation can be observed, the long-lasting outcome is dissatisfying to most of the patients and, therefore, the whole health care system. Theory and methodology The study aims to identify key attributes of coordinated weight loss programmes and elicit patients’ preferences for overweight and obesity therapy in rehabilitation programmes. A self-administered survey measuring attitudes and preferences was conducted in Germany in 2009. Discrete-choice experiment scenarios were developed using a fractional factorial design and results analysed using a random effects logit model. Results N=110 patients completed the questionnaire, 51.82% of these were male, the mean age was 53.05 years and mean body mass index was 33.54 kg/m2 (SD 7.73). A total of 823 choices could be included in the final estimation. The most important aspects for the respondents’ selection were care coordination (coefficient 1.473; SE 0.185) and individual therapy (coefficient 1.446; SE 0.188). The aspect ‘infrastructure of care’ (coefficient 0.570; SE 0.175) was less relevant. All attributes led to significant coefficients. Conclusion Patients value coordination of care and individual therapy most highly. So weight reduction therapy should enable patients to receive a structured, coordinated and interpersonal therapy that is tailored to their personal needs, behaviour and circumstances. Patients are willing to forego infrastructure quality in favour of better coordination and structure in their therapy. PMID:24179457

  12. Patients' Preferences for the Treatment of Metastatic Castrate-resistant Prostate Cancer: A Discrete Choice Experiment.

    PubMed

    Eliasson, Lina; de Freitas, Hayley M; Dearden, Lindsay; Calimlim, Brian; Lloyd, Andrew J

    2017-04-01

    Patient treatment preferences are increasingly being used to inform health care decision making. This discrete choice experiment assessed how men perceive the risks and benefits of hypothetical treatment options for metastatic castrate-resistant prostate cancer (mCRPC). Treatment attributes for inclusion were identified through a review of the literature and product labels. Expert interviews confirmed clinical appropriateness and patient relevance of the attributes, which included effectiveness (delay in months before chemotherapy), steroid use, possible drug interactions (additional hospital visits for monitoring), fogginess (effects on cognition and memory), fatigue (extreme tiredness), food restrictions, and bone pain. Following a pilot, the final discrete choice experiment included 18 choice sets presenting treatments for mCRPC and was completed by men with mCRPC in France, Germany, and the United Kingdom. Data were analyzed using a conditional logit model, with odds ratios (ORs) used to indicate preference for attributes, and tradeoff measures (TOM) were estimated using the ratio of coefficients. Within each attribute category and with all other factors being equal, participants (N = 285) indicated a strong preference for treatments that fully control bone pain (OR = 12.069 [95% CI, 10.555-13.800]) and for treatments that delay chemotherapy (OR, 1.727 [95% CI, 1.548-1.927]). They also preferred treatments that were associated with the lowest risk of fogginess (OR, 2.115 [95% CI, 1.849-2.420]), a lower risk of fatigue (OR, 1.365 [95% CI 1.219-1.528]), and fewer additional hospital visits (OR, 1.245 [95% CI 1.111-1.397]) than the respective reference categories. Participants preferred to use steroids under advice from a physician (OR, 1.275 [95% CI 1.132-1.437]). Food restrictions related to taking medication were not a significant concern for participants. TOM results indicated that large tradeoffs in effectiveness, fogginess, and fatigue are required for

  13. Reduced discretization error in HZETRN

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Slaba, Tony C., E-mail: Tony.C.Slaba@nasa.gov; Blattnig, Steve R., E-mail: Steve.R.Blattnig@nasa.gov; Tweed, John, E-mail: jtweed@odu.edu

    2013-02-01

    The deterministic particle transport code HZETRN is an efficient analysis tool for studying the effects of space radiation on humans, electronics, and shielding materials. In a previous work, numerical methods in the code were reviewed, and new methods were developed that further improved efficiency and reduced overall discretization error. It was also shown that the remaining discretization error could be attributed to low energy light ions (A < 4) with residual ranges smaller than the physical step-size taken by the code. Accurately resolving the spectrum of low energy light particles is important in assessing risk associated with astronaut radiation exposure.more » In this work, modifications to the light particle transport formalism are presented that accurately resolve the spectrum of low energy light ion target fragments. The modified formalism is shown to significantly reduce overall discretization error and allows a physical approximation to be removed. For typical step-sizes and energy grids used in HZETRN, discretization errors for the revised light particle transport algorithms are shown to be less than 4% for aluminum and water shielding thicknesses as large as 100 g/cm{sup 2} exposed to both solar particle event and galactic cosmic ray environments.« less

  14. Divergent Preferences for HIV Prevention: A Discrete Choice Experiment for Multipurpose HIV Prevention Products in South Africa.

    PubMed

    Quaife, Matthew; Eakle, Robyn; Cabrera Escobar, Maria A; Vickerman, Peter; Kilbourne-Brook, Maggie; Mvundura, Mercy; Delany-Moretlwe, Sinead; Terris-Prestholt, Fern

    2018-01-01

    The development of antiretroviral (ARV)-based prevention products has the potential to substantially change the HIV prevention landscape; yet, little is known about how appealing these products will be outside of clinical trials, as compared with the existing options. We conducted a discrete choice experiment (DCE) to measure preferences for 5 new products among 4 important populations in the HIV response: adult men and women in the general population (aged 18 to 49 y), adolescent girls (aged 16 to 17 y), and self-identifying female sex workers (aged 18 to 49 y). We interviewed 661 self-reported HIV-negative participants in peri-urban South Africa, who were asked to choose between 3 unique, hypothetical products over 10 choice sets. Data were analyzed using multinomial, latent class and mixed multinomial logit models. HIV protection was the most important attribute to respondents; however, results indicate significant demand among all groups for multipurpose prevention products that offer protection from HIV infection, other STIs, and unwanted pregnancy. All groups demonstrated a strong preference for long-lasting injectable products. There was substantial heterogeneity in preferences within and across population groups. Hypothetical DCE data may not mirror real-world choices, and products will have more attributes in reality than represented in choice tasks. Background data on participants, including sensitive areas of HIV status and condom use, was self-reported. These results suggest that stimulating demand for new HIV prevention products may require a more a nuanced approach than simply developing highly effective products. No single product is likely to be equally attractive or acceptable across different groups. This study strengthens the call for effective and attractive multipurpose prevention products to be deployed as part of a comprehensive combination prevention strategy.

  15. Can Public Transportation Improve Students' Access to Denver's Best Schools of Choice?

    ERIC Educational Resources Information Center

    Gross, Bethany; Denice, Patrick

    2017-01-01

    Transportation remains a vexing concern in cities that offer students school choice. Time and again, research has shown that families typically want high-performing schools or schools with unique academic programs. But those schools tend to be concentrated in a city's affluent neighborhoods, often long distances from low-income households and…

  16. The choice and preference for public-private health care among urban residents in China: evidence from a discrete choice experiment.

    PubMed

    Tang, Chengxiang; Xu, Judy; Zhang, Meng

    2016-10-18

    Public health care dominated the services provision in China before 1980s. However, the number of private health care providers in China has been increasing since then. The growth of private hospitals escalated after a market-oriented reform was implemented in 2001. Through an experimental approach, this study aims to a better understanding of the dynamic change in preference of health care utilisation among the residents in urban China. Based on a discrete choice experiment (DCE) from a random sample of respondents in urban China, the study evaluated preference over health care attributes affecting individuals' choice for the utilisation of hospital health care. The marginal willingness-to-pay for five health care attributes was estimated, including public/private provision of health care, by analysing mixed logit and latent class models. The results indicated a significantly negative marginal willingness-to-pay for private health care, which was interpreted as representing people's previous interactions with the health care system. The latent class model further suggested preference heterogeneity across our sample. We found that Hukou type, a typical indicator of socioeconomic background, was significantly related to respondents' preference for health care utilisation. Permanent urban residents (urban Hukou) valued private health care less; in contrast rural migrants (rural Hukou) were more likely to be indifferent between public/private provision. Urban residents in China showed a high disposition to obtain health care from the public providers of health care. Our results have implications in the context of the Chinese government attempts to expand the private health care sector in the short term. Policy makers need to consider residents' preference for health care in health policy development as the preference can only change in the long term.

  17. Discrete-Choice Modeling Of Non-Working Women’s Trip-Chaining Activity Based

    NASA Astrophysics Data System (ADS)

    Hayati, Amelia; Pradono; Purboyo, Heru; Maryati, Sri

    2018-05-01

    Start The urban developments of technology and economics are now changing the lifestyles of the urban societies. It is also changing their travel demand to meet their movement needs. Nowadays, urban women, especially in Bandung, West Java, have a high demand for their daily travel and tend to increase. They have the ease of accessibility to personal modes of transportation and freedom to go anywhere to meet their personal and family needs. This also happens to non-working women or as housewives in the city of Bandung. More than 50% of women’s mobility is outside the home, in the term of trip-chaining, from leaving to returning home in one day. It is based on their complex activities in order to meet the needs of family and home care. While less than 60% of male’s mobility is outdoors, it is a simple trip-chaining or only has a single trip. The trip-chaining has significant differences between non-working women and working-men. This illustrates the pattern of Mom and Dad’s mobility in a family with an activity-based approach for the same purpose, i.e. family welfare. This study explains how complex the trip-chaining of non-working urban women and as housewives, with an activity-based approach done outdoors in a week. Socio-economic and household demographic variables serve as the basis for measuring the independent variables affecting family welfare, as well as the variables of type, time and duration of activities performed by unemployed housewives. This study aims to examine the interrelationships between activity variables, especially the time of activity and travel, and socio-economic of household variables that can generate the complexity of women’s daily travel. Discrete Choice Modeling developed by Ben-Akiva, Chandra Bhat, etc., is used in this study to illustrate the relationship between activity and socio-economic demographic variables based on primary survey data in Bandung, West Java for 466 unemployed housewives. The results of the regression, by

  18. The effect of presenting information about invasive follow-up testing on individuals' noninvasive colorectal cancer screening participation decision: results from a discrete choice experiment.

    PubMed

    Benning, Tim M; Dellaert, Benedict G C; Severens, Johan L; Dirksen, Carmen D

    2014-07-01

    Many national colorectal cancer screening campaigns have a similar structure. First, individuals are invited to take a noninvasive screening test, and, second, in the case of a positive screening test result, they are advised to undergo a more invasive follow-up test. The objective of this study was to investigate how much individuals' participation decision in noninvasive screening is affected by the presence or absence of detailed information about invasive follow-up testing and how this effect varies over screening tests. We used a labeled discrete choice experiment of three noninvasive colorectal cancer screening types with two versions that did or did not present respondents with detailed information about the possible invasive follow-up test (i.e., colonoscopy) and its procedure. We used data from 631 Dutch respondents aged 55 to 75 years. Each respondent received only one of the two versions (N = 310 for the invasive follow-up test information specification version, and N = 321 for the no-information specification version). Mixed logit model results show that detailed information about the invasive follow-up test negatively affects screening participation decisions. This effect can be explained mainly by a decrease in choice shares for the most preferred screening test (a combined stool and blood sample test). Choice share simulations based on the discrete choice experiment indicated that presenting invasive follow-up test information decreases screening participation by 4.79%. Detailed information about the invasive follow-up test has a negative effect on individuals' screening participation decisions in noninvasive colorectal cancer screening campaigns. This result poses new challenges for policymakers who aim not only to increase uptake but also to provide full disclosure to potential screening participants. Copyright © 2014 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  19. What influences persistence with medicines? A multinational discrete choice experiment of 2549 patients.

    PubMed

    Holmes, Emily A F; Morrison, Valerie L; Hughes, Dyfrig A

    2016-08-01

    The aim was to examine patients' stated preferences to persist with medicines and to explore the influence of psychosocial and sociocognitive factors. Community-dwelling, hypertensive patients recruited from nine European countries were invited to complete a discrete choice experiment (DCE) with attributes for treatment benefits, mild yet common adverse drug reactions (ADRs), rare but potentially life-threatening ADRs and dosing frequency. Patients responded to the binary choice of which medicine would they be most likely to continue taking. Data were analyzed using a random effects logit model. Two thousand five hundred and forty-nine patients from Austria (n = 321), Belgium (n = 175), England (n = 315), Germany (n = 266), Greece (n = 288), Hungary (n = 322), the Netherlands (n = 231), Poland (n = 312) and Wales (n = 319) completed the DCE. All attributes significantly influenced patients' stated preference to persist with medications (P < 0.05). Patients were willing to accept decreases in treatment benefits of 50.6 percentage points (95% CI 46.1, 57.9) for a very rare (as opposed to rare) risk of severe ADR, 28.3 percentage points (95% CI 25.2, 33.1) for a once daily instead of twice daily dosing and 0.74 percentage points (95% CI 0.67, 0.85) for a 1% point reduction in mild ADRs. Models accounting for psychosocial and sociocognitive characteristics were significantly different from the base case. Patients' intention to persist with treatment was associated with their willingness to trade potential benefits, harms and dosing frequency. Psychosocial and sociocognitive factors influenced the extent of trading. The utility model may have value in assessing patients' likelihood of persisting with medicines and to tailor treatment to maximize persistence. © 2016 The British Pharmacological Society.

  20. Rural practice preferences among medical students in Ghana: a discrete choice experiment

    PubMed Central

    Johnson, Jennifer C; Gyakobo, Mawuli; Agyei-Baffour, Peter; Asabir, Kwesi; Kotha, S Rani; Kwansah, Janet; Nakua, Emmanuel; Snow, Rachel C; Dzodzomenyo, Mawuli

    2010-01-01

    Abstract Objective To determine how specific job attributes influenced fourth year medical students’ stated preference for hypothetical rural job postings in Ghana. Methods Based on discussions with medical student focus groups and physicians in practice and in the Ministry of Health, we created a discrete choice experiment (DCE) that assessed how students’ stated preference for certain rural postings was influenced by various job attributes: a higher salary, free superior housing, an educational allowance for children, improved equipment, supportive management, shorter contracts before study leave and a car. We conducted the DCE among all fourth year medical students in Ghana using a brief structured questionnaire and used mixed logit models to estimate the utility of each job attribute. Findings Complete data for DCE analysis were available for 302 of 310 (97%) students. All attribute parameter estimates differed significantly from zero and had the expected signs. In the main effects mixed logit model, improved equipment and supportive management were most strongly associated with job preference (β = 1.42; 95% confidence interval, CI: 1.17 to 1.66, and β = 1.17; 95% CI: 0.96 to 1.39, respectively), although shorter contracts and salary bonuses were also associated. Discontinuing the provision of basic housing had a large negative influence (β = −1.59; 95% CI: −1.88 to −1.31). In models including gender interaction terms, women’s preferences were more influenced by supportive management and men’s preferences by superior housing. Conclusion Better working conditions were strongly associated with the stated choice of hypothetical rural postings among fourth year Ghanaian medical students. Studies are needed to find out whether job attributes determine the actual uptake of rural jobs by graduating physicians. PMID:20458371

  1. Particle tracking approach for transport in three-dimensional discrete fracture networks: Particle tracking in 3-D DFNs

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Makedonska, Nataliia; Painter, Scott L.; Bui, Quan M.

    The discrete fracture network (DFN) model is a method to mimic discrete pathways for fluid flow through a fractured low-permeable rock mass, and may be combined with particle tracking simulations to address solute transport. However, experience has shown that it is challenging to obtain accurate transport results in three-dimensional DFNs because of the high computational burden and difficulty in constructing a high-quality unstructured computational mesh on simulated fractures. We present a new particle tracking capability, which is adapted to control volume (Voronoi polygons) flow solutions on unstructured grids (Delaunay triangulations) on three-dimensional DFNs. The locally mass-conserving finite-volume approach eliminates massmore » balance-related problems during particle tracking. The scalar fluxes calculated for each control volume face by the flow solver are used to reconstruct a Darcy velocity at each control volume centroid. The groundwater velocities can then be continuously interpolated to any point in the domain of interest. The control volumes at fracture intersections are split into four pieces, and the velocity is reconstructed independently on each piece, which results in multiple groundwater velocities at the intersection, one for each fracture on each side of the intersection line. This technique enables detailed particle transport representation through a complex DFN structure. Verified for small DFNs, the new simulation capability enables numerical experiments on advective transport in large DFNs to be performed. As a result, we demonstrate this particle transport approach on a DFN model using parameters similar to those of crystalline rock at a proposed geologic repository for spent nuclear fuel in Forsmark, Sweden.« less

  2. Particle tracking approach for transport in three-dimensional discrete fracture networks: Particle tracking in 3-D DFNs

    DOE PAGES

    Makedonska, Nataliia; Painter, Scott L.; Bui, Quan M.; ...

    2015-09-16

    The discrete fracture network (DFN) model is a method to mimic discrete pathways for fluid flow through a fractured low-permeable rock mass, and may be combined with particle tracking simulations to address solute transport. However, experience has shown that it is challenging to obtain accurate transport results in three-dimensional DFNs because of the high computational burden and difficulty in constructing a high-quality unstructured computational mesh on simulated fractures. We present a new particle tracking capability, which is adapted to control volume (Voronoi polygons) flow solutions on unstructured grids (Delaunay triangulations) on three-dimensional DFNs. The locally mass-conserving finite-volume approach eliminates massmore » balance-related problems during particle tracking. The scalar fluxes calculated for each control volume face by the flow solver are used to reconstruct a Darcy velocity at each control volume centroid. The groundwater velocities can then be continuously interpolated to any point in the domain of interest. The control volumes at fracture intersections are split into four pieces, and the velocity is reconstructed independently on each piece, which results in multiple groundwater velocities at the intersection, one for each fracture on each side of the intersection line. This technique enables detailed particle transport representation through a complex DFN structure. Verified for small DFNs, the new simulation capability enables numerical experiments on advective transport in large DFNs to be performed. As a result, we demonstrate this particle transport approach on a DFN model using parameters similar to those of crystalline rock at a proposed geologic repository for spent nuclear fuel in Forsmark, Sweden.« less

  3. Individual decisions to vaccinate one's child or oneself: A discrete choice experiment rejecting free-riding motives.

    PubMed

    Verelst, Frederik; Willem, Lander; Kessels, Roselinde; Beutels, Philippe

    2018-06-01

    It is essential for public health to understand what drives people's hesitance towards vaccination. Theoretical models of vaccination decisions are ubiquitous, often incorporating herd immunity, perceptions of vaccine-related side-effects (VRSE) and of vaccine-preventable burden of disease, but with little to no empirical exploration. Herd immunity is a (usually) positive externality where vaccinated individuals influence others' risks by their reduced capability to transmit an infectious disease to them. It is often assumed that (rational) individuals incorporate this externality in their strategic vaccination decision, from which free-riding behavior arises. We performed a Bayesian D-efficient discrete choice experiment in February-March 2017 to study vaccination behavior in 1919 Belgian respondents. Choice sets with vaccine profiles were constructed using six attributes: vaccine effectiveness, VRSE, accessibility (in terms of convenience and reimbursement), vaccine-preventable burden of disease, local (respondents' network of contacts) vaccination coverage, and population (the population at large) vaccination coverage. VRSE and accessibility are the most influential attributes, followed by vaccine effectiveness and burden of disease. Both population and local coverage are less important than the other attributes, but show a significant direct linear relationship with vaccine utility. This supports the existence of peer influence (more incentivized as more and more vaccinate), rather than free-riding on herd immunity. These findings were independent of whether respondents made vaccine choices for themselves or for their child. Around 40% of the respondents indicated accepting vaccination with little or no questioning. These 'acceptors' were less sensitive to changes in the vaccine-preventable burden of disease for their child's vaccination choices (but not for themselves). Public health institutions are critical in stimulating vaccine uptake by making vaccines

  4. Investigating consumers' and informal carers' views and preferences for consumer directed care: A discrete choice experiment.

    PubMed

    Kaambwa, Billingsley; Lancsar, Emily; McCaffrey, Nicola; Chen, Gang; Gill, Liz; Cameron, Ian D; Crotty, Maria; Ratcliffe, Julie

    2015-09-01

    Consumer directed care (CDC) is currently being embraced internationally as a means to promote autonomy and choice for consumers (people aged 65 and over) receiving community aged care services (CACSs). CDC involves giving CACS clients (consumers and informal carers of consumers) control over how CACSs are administered. However, CDC models have largely developed in the absence of evidence on clients' views and preferences. We explored CACS clients' preferences for a variety of CDC attributes and identified factors that may influence these preferences and potentially inform improved design of future CDC models. Study participants were clients of CACSs delivered by five Australian providers. Using a discrete choice experiment (DCE) approach undertaken in a group setting between June and December 2013, we investigated the relative importance to CACS consumers and informal (family) carers of gradations relating to six salient features of CDC (choice of service provider(s), budget management, saving unused/unspent funds, choice of support/care worker(s), support-worker flexibility and level of contact with service coordinator). The DCE data were analysed using conditional, mixed and generalised logit regression models, accounting for preference and scale heterogeneity. Mean ages for 117 study participants were 80 years (87 consumers) and 74 years (30 informal carers). All participants preferred a CDC approach that allowed them to: save unused funds from a CACS package for future use; have support workers that were flexible in terms of changing activities within their CACS care plan and; choose the support workers that provide their day-to-day CACSs. The CDC attributes found to be important to both consumers and informal carers receiving CACSs will inform the design of future CDC models of service delivery. The DCE approach used in this study has the potential for wide applicability and facilitates the assessment of preferences for elements of potential future aged care

  5. What Do Patients Want from Otolaryngologists? A Discrete Choice Experiment.

    PubMed

    Naunheim, Matthew R; Rathi, Vinay K; Naunheim, Margaret L; Alkire, Blake C; Lam, Allen C; Song, Phillip C; Shrime, Mark G

    2017-10-01

    Objectives Patient preferences are crucial for the delivery of patient-centered care. Discrete choice experiments (DCEs) are an emerging quantitative methodology used for understanding these preferences. In this study, we employed DCE techniques to understand the preferences of patients presenting for an ear, nose, and throat clinic visit. Study Design DCE. Setting Decision science laboratory. Methods A DCE survey of 5 attributes-wait time, physician experience, physician personality, utilization of visit time, and cost/copayment-was constructed with structured qualitative interviews with patients. The DCE was administered to participants from the general population, who chose among hypothetical scenarios that varied across these attributes. A conditional logit model was used to determine relative attribute importance, with a separate logit model for determining subject effects. Results A total of 161 participants were included. Cost/copayment had the greatest impact on decision making (importance, 32.2%), followed by wait time and physician experience (26.5% and 24.7%, respectively). Physician personality mattered least (4.7%), although all attributes were significantly correlated to decision making. Participants preferred doctors who spent more time performing physical examination than listening or explaining. Participants were willing to pay $52 extra to avoid a 4-week delay in appointment time; $87 extra for a physician with 10 years of experience (vs 0 years); and $9 extra for a caring, friendly, and compassionate doctor (vs formal, efficient, and business-like). Conclusion DCEs allow for powerful economic analyses that may help physicians understand patient preferences. Our model showed that cost is an important factor to patients and that patients are willing to pay extra for timely appointments, experience, and thorough physical examination.

  6. On the consistency between nearest-neighbor peridynamic discretizations and discretized classical elasticity models

    DOE PAGES

    Seleson, Pablo; Du, Qiang; Parks, Michael L.

    2016-08-16

    The peridynamic theory of solid mechanics is a nonlocal reformulation of the classical continuum mechanics theory. At the continuum level, it has been demonstrated that classical (local) elasticity is a special case of peridynamics. Such a connection between these theories has not been extensively explored at the discrete level. This paper investigates the consistency between nearest-neighbor discretizations of linear elastic peridynamic models and finite difference discretizations of the Navier–Cauchy equation of classical elasticity. While nearest-neighbor discretizations in peridynamics have been numerically observed to present grid-dependent crack paths or spurious microcracks, this paper focuses on a different, analytical aspect of suchmore » discretizations. We demonstrate that, even in the absence of cracks, such discretizations may be problematic unless a proper selection of weights is used. Specifically, we demonstrate that using the standard meshfree approach in peridynamics, nearest-neighbor discretizations do not reduce, in general, to discretizations of corresponding classical models. We study nodal-based quadratures for the discretization of peridynamic models, and we derive quadrature weights that result in consistency between nearest-neighbor discretizations of peridynamic models and discretized classical models. The quadrature weights that lead to such consistency are, however, model-/discretization-dependent. We motivate the choice of those quadrature weights through a quadratic approximation of displacement fields. The stability of nearest-neighbor peridynamic schemes is demonstrated through a Fourier mode analysis. Finally, an approach based on a normalization of peridynamic constitutive constants at the discrete level is explored. This approach results in the desired consistency for one-dimensional models, but does not work in higher dimensions. The results of the work presented in this paper suggest that even though nearest

  7. MCDA swing weighting and discrete choice experiments for elicitation of patient benefit-risk preferences: a critical assessment.

    PubMed

    Tervonen, Tommi; Gelhorn, Heather; Sri Bhashyam, Sumitra; Poon, Jiat-Ling; Gries, Katharine S; Rentz, Anne; Marsh, Kevin

    2017-12-01

    Multiple criteria decision analysis swing weighting (SW) and discrete choice experiments (DCE) are appropriate methods for capturing patient preferences on treatment benefit-risk trade-offs. This paper presents a qualitative comparison of the 2 methods. We review and critically assess similarities and differences of SW and DCE based on 6 aspects: comprehension by study participants, cognitive biases, sample representativeness, ability to capture heterogeneity in preferences, reliability and validity, and robustness of the results. The SW choice task can be more difficult, but the workshop context in which SW is conducted may provide more support to patients who are unfamiliar with the end points being evaluated or who have cognitive impairments. Both methods are similarly prone to a number of biases associated with preference elicitation, and DCE is prone to simplifying heuristics, which limits its application with large number of attributes. The low cost per patient of the DCE means that it can be better at achieving a representative sample, though SW does not require such large sample sizes due to exact nature of the collected preference data. This also means that internal validity is automatically enforced with SW, while the internal validity of DCE results needs to be assessed manually. Choice between the 2 methods depends on characteristics of the benefit-risk assessment, especially on how difficult the trade-offs are for the patients to make and how many patients are available. Although there exist some empirical studies on many of the evaluation aspects, critical evidence gaps remain. Copyright © 2017 John Wiley & Sons, Ltd.

  8. Women's preferences for obstetric care in rural Ethiopia: a population-based discrete choice experiment in a region with low rates of facility delivery.

    PubMed

    Kruk, M E; Paczkowski, M M; Tegegn, A; Tessema, F; Hadley, C; Asefa, M; Galea, S

    2010-11-01

    Delivery attended by skilled professionals is essential to reducing maternal mortality. Although the facility delivery rate in Ethiopia's rural areas is extremely low, little is known about which health system characteristics most influence women's preferences for delivery services. In this study, women's preferences for attributes of health facilities for delivery in rural Ethiopia were investigated. A population-based discrete choice experiment (DCE) was fielded in Gilgel Gibe, in southwest Ethiopia, among women with a delivery in the past 5 years. Women were asked to select a hypothetical health facility for future delivery from two facilities on a picture card. A hierarchical Bayesian procedure was used to estimate utilities associated with facility attributes: distance, type of provider, provider attitude, drugs and medical equipment, transport and cost. 1006 women completed 8045 DCE choice tasks. Among them, 93.8% had delivered their last child at home. The attributes with the greatest influence on the overall utility of a health facility for delivery were availability of drugs and equipment (mean β=3.9, p<0.01), seeing a doctor versus a health extension worker (mean β=2.1, p<0.01) and a receptive provider attitude (mean β=1.4, p<0.01). Women in rural southwest Ethiopia who have limited personal experience with facility delivery nonetheless value health facility attributes that indicate high technical quality: availability of drugs and equipment and physician providers. Well-designed policy experiments that measure the contribution of quality improvements to facility delivery rates in Ethiopia and other countries with low health service utilisation and high maternal mortality may inform national efforts to reduce maternal mortality.

  9. Discrete-Slots Models of Visual Working-Memory Response Times

    PubMed Central

    Donkin, Christopher; Nosofsky, Robert M.; Gold, Jason M.; Shiffrin, Richard M.

    2014-01-01

    Much recent research has aimed to establish whether visual working memory (WM) is better characterized by a limited number of discrete all-or-none slots or by a continuous sharing of memory resources. To date, however, researchers have not considered the response-time (RT) predictions of discrete-slots versus shared-resources models. To complement the past research in this field, we formalize a family of mixed-state, discrete-slots models for explaining choice and RTs in tasks of visual WM change detection. In the tasks under investigation, a small set of visual items is presented, followed by a test item in 1 of the studied positions for which a change judgment must be made. According to the models, if the studied item in that position is retained in 1 of the discrete slots, then a memory-based evidence-accumulation process determines the choice and the RT; if the studied item in that position is missing, then a guessing-based accumulation process operates. Observed RT distributions are therefore theorized to arise as probabilistic mixtures of the memory-based and guessing distributions. We formalize an analogous set of continuous shared-resources models. The model classes are tested on individual subjects with both qualitative contrasts and quantitative fits to RT-distribution data. The discrete-slots models provide much better qualitative and quantitative accounts of the RT and choice data than do the shared-resources models, although there is some evidence for “slots plus resources” when memory set size is very small. PMID:24015956

  10. Patients' and urologists' preferences for prostate cancer treatment: a discrete choice experiment

    PubMed Central

    de Bekker-Grob, E W; Bliemer, M C J; Donkers, B; Essink-Bot, M-L; Korfage, I J; Roobol, M J; Bangma, C H; Steyerberg, E W

    2013-01-01

    Background: Patients' preferences are important for shared decision making. Therefore, we investigated patients' and urologists' preferences for treatment alternatives for early prostate cancer (PC). Methods: A discrete choice experiment was conducted among 150 patients who were waiting for their biopsy results, and 150 urologists. Regression analysis was used to determine patients' and urologists' stated preferences using scenarios based on PC treatment modality (radiotherapy, surgery, and active surveillance (AS)), and risks of urinary incontinence and erectile dysfunction. Results: The response rate was 110 out of 150 (73%) for patients and 50 out of 150 (33%) for urologists. Risk of urinary incontinence was an important determinant of both patients' and urologists' stated preferences for PC treatment (P<0.05). Treatment modality also influenced patients' stated preferences (P<0.05), whereas the risk of erectile dysfunction due to radiotherapy was mainly important to urologists (P<0.05). Both patients and urologists preferred AS to radical treatment, with the exception of patients with anxious/depressed feelings who preferred radical treatment to AS. Conclusion: Although patients and urologists generally may prefer similar treatments for PC, they showed different trade-offs between various specific treatment aspects. This implies that urologists need to be aware of potential differences compared with the patient's perspective on treatment decisions in shared decision making on PC treatment. PMID:23860533

  11. An Australian discrete choice experiment to value eq-5d health states.

    PubMed

    Viney, Rosalie; Norman, Richard; Brazier, John; Cronin, Paula; King, Madeleine T; Ratcliffe, Julie; Street, Deborah

    2014-06-01

    Conventionally, generic quality-of-life health states, defined within multi-attribute utility instruments, have been valued using a Standard Gamble or a Time Trade-Off. Both are grounded in expected utility theory but impose strong assumptions about the form of the utility function. Preference elicitation tasks for both are complicated, limiting the number of health states that each respondent can value and, therefore, that can be valued overall. The usual approach has been to value a set of the possible health states and impute values for the remainder. Discrete Choice Experiments (DCEs) offer an attractive alternative, allowing investigation of more flexible specifications of the utility function and greater coverage of the response surface. We designed a DCE to obtain values for EQ-5D health states and implemented it in an Australia-representative online panel (n = 1,031). A range of specifications investigating non-linear preferences with respect to time and interactions between EQ-5D levels were estimated using a random-effects probit model. The results provide empirical support for a flexible utility function, including at least some two-factor interactions. We then constructed a preference index such that full health and death were valued at 1 and 0, respectively, to provide a DCE-based algorithm for Australian cost-utility analyses. Copyright © 2013 John Wiley & Sons, Ltd.

  12. Valuing Attributes of Home Palliative Care With Service Users: A Pilot Discrete Choice Experiment.

    PubMed

    Gomes, Barbara; de Brito, Maja; Sarmento, Vera P; Yi, Deokhee; Soares, Duarte; Fernandes, Jacinta; Fonseca, Bruno; Gonçalves, Edna; Ferreira, Pedro L; Higginson, Irene J

    2017-12-01

    Discrete choice experiment (DCE) is a quantitative method that helps determine which service attributes are most valued by people and consequently improve their well-being. The objective of this study was to test a new DCE on home palliative care (HPC). Cross-sectional survey using the DCE method with adult patients and their family caregivers, users of three HPC services in Portugal. Service attributes were based on a Cochrane review, a meta-ethnography, and the few existing DCEs on HPC: 1) team's availability, 2) support for family caregivers, 3) homecare support, 4) information and planning, and 5) waiting time. The experimental design consisted in three blocks of eight choice sets where participants chose between two service alternatives that combined different levels of each attribute. We piloted the DCE using cognitive interviewing. Interviews were analyzed for difficulties using Tourangeau's model of information processing. The DCE was conducted with 21 participants of 37 eligible (10 patients with median Palliative Performance Scale score = 45, 11 caregivers). Most participants found the DCE easy (median 2 from 1 to 5), although two patients did not finish the exercise. Key difficulties related to comprehension (e.g., waiting time sometimes understood as response time for visit instead of time from referral to care start) and judgment (e.g., indecision due to similar service alternatives). The DCE method is feasible and acceptable but not all patients are able to participate. In the main study phase, we will give more attention to the explanation of the waiting time attribute. Copyright © 2017 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.

  13. Factors influencing job preferences of health workers providing obstetric care: results from discrete choice experiments in Malawi, Mozambique and Tanzania.

    PubMed

    McAuliffe, Eilish; Galligan, Marie; Revill, Paul; Kamwendo, Francis; Sidat, Mohsin; Masanja, Honorati; de Pinho, Helen; Araujo, Edson

    2016-12-20

    Task shifting from established health professionals to mid-level providers (MLPs) (professionals who undergo shorter training in specific procedures) is one key strategy for reducing maternal and neonatal deaths. This has resulted in a growth in cadre types providing obstetric care in low and middle-income countries. Little is known about the relative importance of the different factors in determining motivation and retention amongst these cadres. This paper presents findings from large sample (1972 respondents) discrete choice experiments to examine the employment preferences of obstetric care workers across three east African countries. The strongest predictors of job choice were access to continuing professional development and the presence of functioning human resources management (transparent, accountable and consistent systems for staff support, supervision and appraisal). Consistent with similar works we find pay and allowances significantly positively related to utility, but financial rewards are not as fundamental a factor underlying employment preferences as many may have previously believed. Location (urban vs rural) had the smallest average effect on utility for job choice in all three countries. These findings are important in the context where efforts to address the human resources crisis have focused primarily on increasing salaries and incentives, as well as providing allowances to work in rural areas.

  14. 34 CFR 200.48 - Funding for choice-related transportation and supplemental educational services.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false Funding for choice-related transportation and supplemental educational services. 200.48 Section 200.48 Education Regulations of the Offices of the Department of Education OFFICE OF ELEMENTARY AND SECONDARY EDUCATION, DEPARTMENT OF EDUCATION TITLE I-IMPROVING...

  15. Survival or Mortality: Does Risk Attribute Framing Influence Decision-Making Behavior in a Discrete Choice Experiment?

    PubMed

    Veldwijk, Jorien; Essers, Brigitte A B; Lambooij, Mattijs S; Dirksen, Carmen D; Smit, Henriette A; de Wit, G Ardine

    2016-01-01

    To test how attribute framing in a discrete choice experiment (DCE) affects respondents' decision-making behavior and their preferences. Two versions of a DCE questionnaire containing nine choice tasks were distributed among a representative sample of the Dutch population aged 55 to 65 years. The DCE consisted of four attributes related to the decision regarding participation in genetic screening for colorectal cancer (CRC). The risk attribute included was framed positively as the probability of surviving CRC and negatively as the probability of dying from CRC. Panel mixed-logit models were used to estimate the relative importance of the attributes. The data of the positively and negatively framed DCE were compared on the basis of direct attribute ranking, dominant decision-making behavior, preferences, and importance scores. The majority (56%) of the respondents ranked survival as the most important attribute in the positively framed DCE, whereas only a minority (8%) of the respondents ranked mortality as the most important attribute in the negatively framed DCE. Respondents made dominant choices based on survival significantly more often than based on mortality. The framing of the risk attribute significantly influenced all attribute-level estimates and resulted in different preference structures among respondents in the positively and negatively framed data set. Risk framing affects how respondents value the presented risk. Positive risk framing led to increased dominant decision-making behavior, whereas negative risk framing led to risk-seeking behavior. Attribute framing should have a prominent part in the expert and focus group interviews, and different types of framing should be used in the pilot version of DCEs as well as in actual DCEs to estimate the magnitude of the effect of choosing different types of framing. Copyright © 2016 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  16. Rural Clinician Scarcity and Job Preferences of Doctors and Nurses in India: A Discrete Choice Experiment

    PubMed Central

    Rao, Krishna D.; Ryan, Mandy; Shroff, Zubin; Vujicic, Marko; Ramani, Sudha; Berman, Peter

    2013-01-01

    The scarcity of rural doctors has undermined the ability of health systems in low and middle-income countries like India to provide quality services to rural populations. This study examines job preferences of doctors and nurses to inform what works in terms of rural recruitment strategies. Job acceptance of different strategies was compared to identify policy options for increasing the availability of clinical providers in rural areas. In 2010 a Discrete Choice Experiment was conducted in India. The study sample included final year medical and nursing students, and in-service doctors and nurses serving at Primary Health Centers. Eight job attributes were identified and a D-efficient fractional factorial design was used to construct pairs of job choices. Respondent acceptance of job choices was analyzed using multi-level logistic regression. Location mattered; jobs in areas offering urban amenities had a high likelihood of being accepted. Higher salary had small effect on doctor, but large effect on nurse, acceptance of rural jobs. At five times current salary levels, 13% (31%) of medical students (doctors) were willing to accept rural jobs. At half this level, 61% (52%) of nursing students (nurses) accepted a rural job. The strategy of reserving seats for specialist training in exchange for rural service had a large effect on job acceptance among doctors, nurses and nursing students. For doctors and nurses, properly staffed and equipped health facilities, and housing had small effects on job acceptance. Rural upbringing was not associated with rural job acceptance. Incentivizing doctors for rural service is expensive. A broader strategy of substantial salary increases with improved living, working environment, and education incentives is necessary. For both doctors and nurses, the usual strategies of moderate salary increases, good facility infrastructure, and housing will not be effective. Non-physician clinicians like nurse-practitioners offer an affordable

  17. Men's preferences for the treatment of lower urinary tract symptoms associated with benign prostatic hyperplasia: a discrete choice experiment.

    PubMed

    Mankowski, Colette; Ikenwilo, Divine; Heidenreich, Sebastian; Ryan, Mandy; Nazir, Jameel; Newman, Cathy; Watson, Verity

    2016-01-01

    To explore and quantify men's preferences and willingness to pay (WTP) for attributes of medications for lower urinary tract symptoms associated with benign prostatic hyperplasia using a discrete choice experiment. Men in the UK aged ≥45 years with moderate-to-severe lower urinary tract symptoms/benign prostatic hyperplasia (based on self-reported International Prostate Symptom Score ≥8) were recruited. An online discrete choice experiment survey was administered. Eligible men were asked to consider different medication scenarios and select their preferred medication according to seven attributes: daytime and nighttime (nocturia) urinary frequency, urinary urgency, sexual and nonsexual side effects, number of tablets/day, and cost/month. A mixed-logit model was used to estimate preferences and WTP for medication attributes. In all, 247 men completed the survey. Men were willing to trade-off symptom improvements and treatment side effects. Men preferred medications that reduced urinary urgency and reduced day- and nighttime urinary frequency. Men preferred medications without side effects (base-case level), but did not care about the number of tablets per day. WTP for symptomatic improvement was £25.33/month for reduced urgency (urge incontinence to mild urgency), and £6.65/month and £1.39/month for each unit reduction in night- and daytime urination frequency, respectively. The sexual and nonsexual side effects reduced WTP by up to £30.07/month. There was significant heterogeneity in preferences for most attributes, except for reduced urinary urgency from urge incontinence to mild urgency and no fluid during ejaculation (dry orgasm). To compensate for side effects, a medicine for lower urinary tract symptoms/benign prostatic hyperplasia must provide a combination of benefits, such as reduced urgency of urination plus reduced nighttime and/or reduced daytime urination.

  18. The Role of Qualitative Research Methods in Discrete Choice Experiments

    PubMed Central

    Vass, Caroline; Rigby, Dan; Payne, Katherine

    2017-01-01

    Background. The use of qualitative research (QR) methods is recommended as good practice in discrete choice experiments (DCEs). This study investigated the use and reporting of QR to inform the design and/or interpretation of healthcare-related DCEs and explored the perceived usefulness of such methods. Methods. DCEs were identified from a systematic search of the MEDLINE database. Studies were classified by the quantity of QR reported (none, basic, or extensive). Authors (n = 91) of papers reporting the use of QR were invited to complete an online survey eliciting their views about using the methods. Results. A total of 254 healthcare DCEs were included in the review; of these, 111 (44%) did not report using any qualitative methods; 114 (45%) reported “basic” information; and 29 (11%) reported or cited “extensive” use of qualitative methods. Studies reporting the use of qualitative methods used them to select attributes and/or levels (n = 95; 66%) and/or pilot the DCE survey (n = 26; 18%). Popular qualitative methods included focus groups (n = 63; 44%) and interviews (n = 109; 76%). Forty-four studies (31%) reported the analytical approach, with content (n = 10; 7%) and framework analysis (n = 5; 4%) most commonly reported. The survey identified that all responding authors (n = 50; 100%) found that qualitative methods added value to their DCE study, but many (n = 22; 44%) reported that journals were uninterested in the reporting of QR results. Conclusions. Despite recommendations that QR methods be used alongside DCEs, the use of QR methods is not consistently reported. The lack of reporting risks the inference that QR methods are of little use in DCE research, contradicting practitioners’ assessments. Explicit guidelines would enable more clarity and consistency in reporting, and journals should facilitate such reporting via online supplementary materials. PMID:28061040

  19. The Role of Qualitative Research Methods in Discrete Choice Experiments.

    PubMed

    Vass, Caroline; Rigby, Dan; Payne, Katherine

    2017-04-01

    The use of qualitative research (QR) methods is recommended as good practice in discrete choice experiments (DCEs). This study investigated the use and reporting of QR to inform the design and/or interpretation of healthcare-related DCEs and explored the perceived usefulness of such methods. DCEs were identified from a systematic search of the MEDLINE database. Studies were classified by the quantity of QR reported (none, basic, or extensive). Authors ( n = 91) of papers reporting the use of QR were invited to complete an online survey eliciting their views about using the methods. A total of 254 healthcare DCEs were included in the review; of these, 111 (44%) did not report using any qualitative methods; 114 (45%) reported "basic" information; and 29 (11%) reported or cited "extensive" use of qualitative methods. Studies reporting the use of qualitative methods used them to select attributes and/or levels ( n = 95; 66%) and/or pilot the DCE survey ( n = 26; 18%). Popular qualitative methods included focus groups ( n = 63; 44%) and interviews ( n = 109; 76%). Forty-four studies (31%) reported the analytical approach, with content ( n = 10; 7%) and framework analysis ( n = 5; 4%) most commonly reported. The survey identified that all responding authors ( n = 50; 100%) found that qualitative methods added value to their DCE study, but many ( n = 22; 44%) reported that journals were uninterested in the reporting of QR results. Despite recommendations that QR methods be used alongside DCEs, the use of QR methods is not consistently reported. The lack of reporting risks the inference that QR methods are of little use in DCE research, contradicting practitioners' assessments. Explicit guidelines would enable more clarity and consistency in reporting, and journals should facilitate such reporting via online supplementary materials.

  20. Acceptance of vaccinations in pandemic outbreaks: a discrete choice experiment.

    PubMed

    Determann, Domino; Korfage, Ida J; Lambooij, Mattijs S; Bliemer, Michiel; Richardus, Jan Hendrik; Steyerberg, Ewout W; de Bekker-Grob, Esther W

    2014-01-01

    Preventive measures are essential to limit the spread of new viruses; their uptake is key to their success. However, the vaccination uptake in pandemic outbreaks is often low. We aim to elicit how disease and vaccination characteristics determine preferences of the general public for new pandemic vaccinations. In an internet-based discrete choice experiment (DCE) a representative sample of 536 participants (49% participation rate) from the Dutch population was asked for their preference for vaccination programs in hypothetical communicable disease outbreaks. We used scenarios based on two disease characteristics (susceptibility to and severity of the disease) and five vaccination program characteristics (effectiveness, safety, advice regarding vaccination, media attention, and out-of-pocket costs). The DCE design was based on a literature review, expert interviews and focus group discussions. A panel latent class logit model was used to estimate which trade-offs individuals were willing to make. All above mentioned characteristics proved to influence respondents' preferences for vaccination. Preference heterogeneity was substantial. Females who stated that they were never in favor of vaccination made different trade-offs than males who stated that they were (possibly) willing to get vaccinated. As expected, respondents preferred and were willing to pay more for more effective vaccines, especially if the outbreak was more serious (€6-€39 for a 10% more effective vaccine). Changes in effectiveness, out-of-pocket costs and in the body that advises the vaccine all substantially influenced the predicted uptake. We conclude that various disease and vaccination program characteristics influence respondents' preferences for pandemic vaccination programs. Agencies responsible for preventive measures during pandemics can use the knowledge that out-of-pocket costs and the way advice is given affect vaccination uptake to improve their plans for future pandemic outbreaks

  1. Design and analysis of simple choice surveys for natural resource management

    USGS Publications Warehouse

    Fieberg, John; Cornicelli, Louis; Fulton, David C.; Grund, Marrett D.

    2010-01-01

    We used a simple yet powerful method for judging public support for management actions from randomized surveys. We asked respondents to rank choices (representing management regulations under consideration) according to their preference, and we then used discrete choice models to estimate probability of choosing among options (conditional on the set of options presented to respondents). Because choices may share similar unmodeled characteristics, the multinomial logit model, commonly applied to discrete choice data, may not be appropriate. We introduced the nested logit model, which offers a simple approach for incorporating correlation among choices. This forced choice survey approach provides a useful method of gathering public input; it is relatively easy to apply in practice, and the data are likely to be more informative than asking constituents to rate attractiveness of each option separately.

  2. Measuring Preferences for a Diabetes Pay-for-Performance for Patient (P4P4P) Program using a Discrete Choice Experiment.

    PubMed

    Chen, Tsung-Tai; Tung, Tao-Hsin; Hsueh, Ya-Seng Arthur; Tsai, Ming-Han; Liang, Hsiu-Mei; Li, Kay-Lun; Chung, Kuo-Piao; Tang, Chao-Hsiun

    2015-07-01

    To elicit a patient's willingness to participate in a diabetes pay-for-performance for patient (P4P4P) program using a discrete choice experiment method. The survey was conducted in March 2013. Our sample was drawn from patients with diabetes at five hospitals in Taiwan (International Classification of Diseases, Ninth Revision, Clinical Modification code 250). The sample size was 838 patients. The discrete choice experiment questionnaire included the attributes monthly cash rewards, exercise time, diet control, and program duration. We estimated a bivariate probit model to derive willingness-to-accept levels after accounting for the characteristics (e.g., severity and comorbidity) of patients with diabetes. The preferred program was a 3-year program involving 30 minutes of exercise per day and flexible diet control. Offering an incentive of approximately US $67 in cash per month appears to increase the likelihood that patients with diabetes will participate in the preferred P4P4P program by approximately 50%. Patients with more disadvantageous characteristics (e.g., elderly, low income, greater comorbidity, and severity) could have less to gain from participating in the program and thus require a higher monetary incentive to compensate for the disutility caused by participating in the program's activities. Our result demonstrates that a modest financial incentive could increase the likelihood of program participation after accounting for the attributes of the P4P4P program and patients' characteristics. Copyright © 2015 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  3. The effect of traffic lights and regulatory statements on the choice between complementary and conventional medicines in Australia: results from a discrete choice experiment.

    PubMed

    Spinks, Jean; Mortimer, Duncan

    2015-01-01

    It has been suggested that complementary medicines are currently 'under-regulated' in some countries due to their potential for harm as a direct result from side-effects or interactions; from delaying more effective care; or from the economic cost of purchasing an ineffective or inappropriate treatment. The requirement of additional labelling on complementary medicine products has been suggested in Australia and may provide additional information to consumers at the point of purchase. This paper details a unique way of testing the potential effects on consumer behaviour of including either a traffic light logo or regulatory statement on labels. Using a discrete choice experiment, data were collected in 2012 in a sample of 521 Australians with either type 2 diabetes or cardiovascular disease. We find that additional labelling can affect consumer behaviour, but in unpredictable ways. The results of this experiment are informative to further the dialogue concerning possible regulatory mechanisms. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Using qualitative methods for attribute development for discrete choice experiments: issues and recommendations.

    PubMed

    Coast, Joanna; Al-Janabi, Hareth; Sutton, Eileen J; Horrocks, Susan A; Vosper, A Jane; Swancutt, Dawn R; Flynn, Terry N

    2012-06-01

    Attribute generation for discrete choice experiments (DCEs) is often poorly reported, and it is unclear whether this element of research is conducted rigorously. This paper explores issues associated with developing attributes for DCEs and contrasts different qualitative approaches. The paper draws on eight studies, four developed attributes for measures, and four developed attributes for more ad hoc policy questions. Issues that have become apparent through these studies include the following: the theoretical framework for random utility theory and the need for attributes that are neither too close to the latent construct nor too intrinsic to people's personality; the need to think about attribute development as a two-stage process involving conceptual development followed by refinement of language to convey the intended meaning; and the difficulty in resolving tensions inherent in the reductiveness of condensing complex and nuanced qualitative findings into precise terms. The comparison of alternative qualitative approaches suggests that the nature of data collection will depend both on the characteristics of the question (its sensitivity, for example) and the availability of existing qualitative information. An iterative, constant comparative approach to analysis is recommended. Finally, the paper provides a series of recommendations for improving the reporting of this element of DCE studies. Copyright © 2011 John Wiley & Sons, Ltd.

  5. Determining Preferences Related to HIV Counselling and Testing Services Among High School Learners in KwaZulu-Natal: A Discrete Choice Experiment.

    PubMed

    Strauss, Michael; George, Gavin L; Rhodes, Bruce D

    2018-01-01

    A key strategy of the South African national response to HIV is the scale-up of HIV counselling and testing (HCT) in the 15-49 years age group. The integrated school health policy aims to guide the roll out of youth-friendly health services including the provision of HCT in schools. Using a discrete choice experiment to examine preferences regarding the attributes of HCT service packages, this study identifies barriers to and facilitators of HCT among high school learners. Monetary considerations were found to have the strongest effect of any attribute on choice, whilst confidentiality was found to be a primary concern for learners considering HCT. Policy makers and service providers must ensure that confidentiality is maintained, and could consider using monetary incentives as a way of increasing uptake of HCT. Programmes designed to reduce social stigma and improve education and knowledge dissemination around HCT and HIV, are vital in creating demand for HCT and changing attitudes among young people.

  6. Providing Informal Care in Terminal Illness: An Analysis of Preferences for Support Using a Discrete Choice Experiment.

    PubMed

    Hall, Jane; Kenny, Patricia; Hossain, Ishrat; Street, Deborah J; Knox, Stephanie A

    2014-08-01

    The trend for terminally ill patients to receive much of their end-of-life care at home necessitates the design of services to facilitate this. Care at home also requires that informal care be provided by family members and friends. This study investigated informal carers' preferences for support services to aid the development of end-of-life health care services. This cross-sectional study used 2 discrete choice experiments to ascertain the preferences of carers supporting patients with different levels of care need, determined by the assistance needed with personal care and labeled High Care (HC) and Low Care (LC). The sample included 168 informal carers of people receiving palliative care at home from 2 palliative care services in Sydney, Australia. Data were collected in face-to-face interviews; carers chose between 2 hypothetical plans of support services and their current services. Data were analyzed with generalized multinomial logit models that were used to calculate the impact of each attribute on the probability of a carer choosing a service plan. Preferred support included nursing services; the probability of choosing a plan increased significantly if it included nurse home visits and phone advice (P < 0.001). HC carers also wanted doctor home visits, home respite, and help with personal care (P < 0.05), and LC carers wanted help with household tasks, transport, and a case coordinator (P < 0.001). On average, both groups of carers preferred their current services, but this varied with characteristics of the carer and the caregiving situation. The most valued services are those that support carers in their caregiving role; however, supportive care preferences vary with the different circumstances of patients and carers. © The Author(s) 2013.

  7. Understanding Health Workers' Job Preferences to Improve Rural Retention in Timor-Leste: Findings from a Discrete Choice Experiment.

    PubMed

    Smitz, Marc-Francois; Witter, Sophie; Lemiere, Christophe; Eozenou, Patrick Hoang-Vu; Lievens, Tomas; Zaman, Rashid U; Engelhardt, Kay; Hou, Xiaohui

    2016-01-01

    Timor-Leste built its health workforce up from extremely low levels after its war of independence, with the assistance of Cuban training, but faces challenges as the first cohorts of doctors will shortly be freed from their contracts with government. Retaining doctors, nurses and midwives in remote areas requires a good understanding of health worker preferences. The article reports on a discrete choice experiment (DCE) carried out amongst 441 health workers, including 173 doctors, 150 nurses and 118 midwives. Qualitative methods were conducted during the design phase. The attributes which emerged were wages, skills upgrading/specialisation, location, working conditions, transportation and housing. One of the main findings of the study is the relative lack of importance of wages for doctors, which could be linked to high intrinsic motivation, perceptions of having an already highly paid job (relative to local conditions), and/or being in a relatively early stage of their career for most respondents. Professional development provides the highest satisfaction with jobs, followed by the working conditions. Doctors with less experience, males and the unmarried are more flexible about location. For nurses and midwives, skill upgrading emerged as the most cost effective method. The study is the first of its kind conducted in Timor-Leste. It provides policy-relevant information to balance financial and non-financial incentives for different cadres and profiles of staff. It also augments a thin literature on the preferences of working doctors (as opposed to medical students) in low and middle income countries and provides insights into the ability to instil motivation to work in rural areas, which may be influenced by rural recruitment and Cuban-style training, with its emphasis on community service.

  8. Should flavours be banned in cigarettes and e-cigarettes? Evidence on adult smokers and recent quitters from a discrete choice experiment.

    PubMed

    Buckell, John; Marti, Joachim; Sindelar, Jody L

    2018-05-28

    To provide the policy-relevant estimates of impacts of alternative flavour bans on preferences and demand for cigarettes and e-cigarettes in adult smokers and recent quitters. A best-best discrete choice experiment (DCE) is used to elicit smokers' and recent quitters' preferences for flavours, price, health impact and nicotine level in cigarettes and e-cigarettes. Choice of tobacco products and an opt-out option were examined. An efficient design yielded 36 choice sets. Exploded logit choice models were estimated. Flavour bans are modelled by restricting flavour coefficients in the estimated model. A sample of 2031 adult smokers and recent quitters was recruited to complete an online survey and DCE. Current smokers and recent quitters, on average, prefer cigarettes and menthol cigarettes over flavoured e-cigarettes. However, there is substantial preference heterogeneity by younger adults (ages 18-25), race/ethnicity and respondents with higher education. Our predictions suggest that a ban on menthol cigarettes would produce the greatest reduction in the choice of cigarettes (-5.2%), but with an accompanying increase in e-cigarettes use (3.8%). In contrast, banning flavours in e-cigarettes, while allowing menthol in cigarettes would result in the greatest increase in the selection of cigarettes (8.3%), and a decline in the use of e-cigarettes (-11.1%). A ban on all flavours, but tobacco in both products would increase 'opting-out' the most (5.2%) but would also increase choice of cigarettes (2.7%) and decrease choice of e-cigarettes (-7.9%). A ban on flavoured e-cigarettes alone would likely increase the choice of cigarettes in smokers, arguably the more harmful way of obtaining nicotine, whereas a ban on menthol cigarettes alone would likely be more effective in reducing the choice of cigarettes. A ban on all flavours in both products would likely reduce the smoking/vaping rates, but the use of cigarettes would be higher than in the status quo. Policy-makers should

  9. Direct Discrete Method for Neutronic Calculations

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Vosoughi, Naser; Akbar Salehi, Ali; Shahriari, Majid

    The objective of this paper is to introduce a new direct method for neutronic calculations. This method which is named Direct Discrete Method, is simpler than the neutron Transport equation and also more compatible with physical meaning of problems. This method is based on physic of problem and with meshing of the desired geometry, writing the balance equation for each mesh intervals and with notice to the conjunction between these mesh intervals, produce the final discrete equations series without production of neutron transport differential equation and mandatory passing from differential equation bridge. We have produced neutron discrete equations for amore » cylindrical shape with two boundary conditions in one group energy. The correction of the results from this method are tested with MCNP-4B code execution. (authors)« less

  10. Participating physician preferences regarding a pay-for-performance incentive design: a discrete choice experiment.

    PubMed

    Chen, Tsung-Tai; Lai, Mei-Shu; Chung, Kuo-Piao

    2016-02-01

    To determine whether the magnitude of incentives or other design attributes should be prioritized and the most important attributes, according to physicians, of the diabetes P4P (pay-for-performance) program design. We implemented a discrete choice experiment (DCE) to elicit the P4P incentive design-related preferences of physicians. All of the physicians (n = 248) who participated in the diabetes P4P program located in the supervisory area of the northern regional branch of the Bureau of National Health Insurance in 2009 were included. The response rate was ∼ 60%. Our research found that the bonus type of incentive was the most important attribute, followed by the incentive structure and the investment magnitude. Physicians may feel that good P4P designs are more important than the magnitude of the investment by the insurer. The two most important P4P designs include providing the bonus type of incentive and using pay-for-excellence plus pay-for-improvement. © The Author 2015. Published by Oxford University Press in association with the International Society for Quality in Health Care; all rights reserved.

  11. A Generalization Strategy for Discrete Area Feature by Using Stroke Grouping and Polarization Transportation Selection

    NASA Astrophysics Data System (ADS)

    Wang, Xiao; Burghardt, Dirk

    2018-05-01

    This paper presents a new strategy for the generalization of discrete area features by using stroke grouping method and polarization transportation selection. The mentioned stroke is constructed on derive of the refined proximity graph of area features, and the refinement is under the control of four constraints to meet different grouping requirements. The area features which belong to the same stroke are detected into the same group. The stroke-based strategy decomposes the generalization process into two sub-processes by judging whether the area features related to strokes or not. For the area features which belong to the same one stroke, they normally present a linear like pat-tern, and in order to preserve this kind of pattern, typification is chosen as the operator to implement the generalization work. For the remaining area features which are not related by strokes, they are still distributed randomly and discretely, and the selection is chosen to conduct the generalization operation. For the purpose of retaining their original distribution characteristic, a Polarization Transportation (PT) method is introduced to implement the selection operation. Buildings and lakes are selected as the representatives of artificial area feature and natural area feature respectively to take the experiments. The generalized results indicate that by adopting this proposed strategy, the original distribution characteristics of building and lake data can be preserved, and the visual perception is pre-served as before.

  12. What do nurses and midwives value about their jobs? Results from a discrete choice experiment.

    PubMed

    Scott, Anthony; Witt, Julia; Duffield, Christine; Kalb, Guyonne

    2015-01-01

    To examine nurses' and midwives' preferences for the characteristics of their jobs. A discrete choice experiment of 990 nurses and midwives administered as part of a survey of nurses and midwives in Victoria, Australia. Autonomy, working hours, and processes to deal with violence and bullying were valued most highly. Nurses and midwives would be willing to forgo 19% and 16% of their annual income for adequate autonomy and adequate processes to deal with violence and bullying, compared to poor autonomy and poor processes for violence and bullying. They would need to be paid an additional 24% to increase their working hours by 10% ($73 per hour). Job characteristics that were less important were shift work, nurse to patient ratios, and public or private sector work. Policies to improve retention and job satisfaction of nurses and midwives should initially focus on autonomy, processes to deal with violence and bullying, and reasonable working hours. Further research on the cost-effectiveness of these different policies is needed. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  13. [What is important for Israeli women who give birth? Estimation of the preference structure using a Discrete Choice Experiment (DCE)].

    PubMed

    Neuman, Tzahi; Neuman, Einat

    2009-10-01

    This article aims to estimate the preference structure of attributes of maternity-wards, as expressed by Israeli women who recently gave birth. The estimation is based on data generated by an experiment that simulates actual choices of hospital (Discrete Choice experiment). The sample includes 323 women who gave birth in the year 2003 in three large hospitals in the central part of Israel (The Sheba Medical Center, Tel Hashomer; The Rabin Medical Center, Beilinson Campus in Petah Tikva; and the Meir Medical Center in Kfar Saba). It was found that the ranking of attributes (in a descending order in terms of importance) is: professionalism of the staff, attention of staff towards the patient, transfer of information, and travel time from residence to the hospital. Most women who gave birth did not care about the number of beds in the room at hospitalization (that represents the physical facilities). The technique used in this study is unique and can assist policymakers in allocation of funds, analysis of new policies even before they have been implemented and inclusion of new services.

  14. Patient and nurse preferences for implementation of bedside handover: Do they agree? Findings from a discrete choice experiment.

    PubMed

    Whitty, Jennifer A; Spinks, Jean; Bucknall, Tracey; Tobiano, Georgia; Chaboyer, Wendy

    2017-08-01

    To describe and compare patients' and nurses' preferences for the implementation of bedside handover. Discrete choice experiment describing handover choices using six characteristics: whether the patient is invited to participate; whether a family member/carer/friend is invited; the number of nurses present; the level of patient involvement; the information content; and privacy. Two Australian hospitals. Adult patients (n=401) and nurses (n=200) recruited from medical wards. Mean importance scores for handover characteristics estimated using mixed multinomial logit regression of the choice data. Both patient and nurse participants preferred handover at the bedside rather than elsewhere (P<.05). Being invited to participate, supporting strong two-way communication, having a family member/carer/friend present and having two nurses rather than the nursing team present were most important for patients. Patients being invited to participate and supporting strong two-way communication were most important for nurses. However, contrary to patient preferences, having a family member/carer/friend present was not considered important by nurses. Further, while patients expressed a weak preference to have sensitive information handed over quietly at the bedside, nurses expressed a relatively strong preference for handover of sensitive information verbally away from the bedside. All participants strongly support handover at the bedside and want patients to participate although patient and nurse preferences for various aspects of bedside handover differ. An understanding of these preferences is expected to support recommendations for improving the patient hospital experience and the consistent implementation of bedside handover as a safety initiative. © 2016 The Authors. Health Expectations Published by John Wiley & Sons Ltd.

  15. Understanding rational non-adherence to medications. A discrete choice experiment in a community sample in Australia

    PubMed Central

    2012-01-01

    Background In spite of the potential impact upon population health and expenditure, interventions promoting medication adherence have been found to be of moderate effectiveness and cost effectiveness. Understanding the relative influence of factors affecting patient medication adherence decisions and the characteristics of individuals associated with variation in adherence will lead to a better understanding of how future interventions should be designed and targeted. This study aims to explore medication-taking decisions that may underpin intentional medication non-adherence behaviour amongst a community sample and the relative importance of medication specific factors and patient background characteristics contributing to those decisions. Methods A discrete choice experiment conducted through a web-enabled online survey was used to estimate the relative importance of eight medication factors (immediate and long-term medication harms and benefits, cost, regimen, symptom severity, alcohol restrictions) on the preference to continue taking a medication. To reflect more closely what usually occurs in practice, non-disease specific medication and health terms were used to mimic decisions across multiple medications and conditions.161 general community participants, matching the national Australian census data (age, gender) were recruited through an online panel provider (participation rate: 10%) in 2010. Results Six of the eight factors (i.e. immediate and long-term medication harms and benefits, cost, and regimen) had a significant influence on medication choice. Patient background characteristics did not improve the model. Respondents with private health insurance appeared less sensitive to cost then those without private health insurance. In general, health outcomes, framed as a side-effect, were found to have a greater influence over adherence than outcomes framed as therapeutic benefits. Conclusions Medication-taking decisions are the subject of rational choices

  16. Understanding rational non-adherence to medications. A discrete choice experiment in a community sample in Australia.

    PubMed

    Laba, Tracey-Lea; Brien, Jo-Anne; Jan, Stephen

    2012-06-20

    In spite of the potential impact upon population health and expenditure, interventions promoting medication adherence have been found to be of moderate effectiveness and cost effectiveness. Understanding the relative influence of factors affecting patient medication adherence decisions and the characteristics of individuals associated with variation in adherence will lead to a better understanding of how future interventions should be designed and targeted. This study aims to explore medication-taking decisions that may underpin intentional medication non-adherence behaviour amongst a community sample and the relative importance of medication specific factors and patient background characteristics contributing to those decisions. A discrete choice experiment conducted through a web-enabled online survey was used to estimate the relative importance of eight medication factors (immediate and long-term medication harms and benefits, cost, regimen, symptom severity, alcohol restrictions) on the preference to continue taking a medication. To reflect more closely what usually occurs in practice, non-disease specific medication and health terms were used to mimic decisions across multiple medications and conditions.161 general community participants, matching the national Australian census data (age, gender) were recruited through an online panel provider (participation rate: 10%) in 2010. Six of the eight factors (i.e. immediate and long-term medication harms and benefits, cost, and regimen) had a significant influence on medication choice. Patient background characteristics did not improve the model. Respondents with private health insurance appeared less sensitive to cost then those without private health insurance. In general, health outcomes, framed as a side-effect, were found to have a greater influence over adherence than outcomes framed as therapeutic benefits. Medication-taking decisions are the subject of rational choices, influenced by the attributes of

  17. Evaluating Health Workers' Potential Resistance to New Interventions: A Role for Discrete Choice Experiments

    PubMed Central

    Lagarde, Mylene; Smith Paintain, Lucy; Antwi, Gifti; Jones, Caroline; Greenwood, Brian; Chandramohan, Daniel; Tagbor, Harry; Webster, Jayne

    2011-01-01

    Background The currently recommended approach for preventing malaria in pregnancy (MiP), intermittent preventive treatment with sulphadoxine-pyrimethamine (SP-IPT), has been questioned due to the spread of resistance to SP. Whilst trials are underway to test the efficacy of future alternative approaches, it is important to start exploring the feasibility of their implementation. Methods and Findings This study uses a discrete choice experiment (DCE) method to assess the potential resistance of health workers to changing strategies for control of MiP. In Ashanti region in Ghana, 133 antenatal clinic health workers were presented with 16 choice sets of two alternative policy options, each consisting of a bundle of six attributes representing certain clinical guidelines for controlling MiP (type of approach and drug used), possible associated maternal and neo-natal outcomes, workload and financial incentives. The data were analysed using a random effects logit model. Overall, staff showed a preference for a curative approach with pregnant women tested for malaria parasites and treated only if positive, compared to a preventive approach (OR 1.6; p = 0.001). Increasing the incidence of low birth weight or severe anaemia by 1% would reduce the odds of preferring an approach by 18% and 10% respectively. Midwives were more resistant to potential changes to current guidelines than lower-level cadres. Conclusions In Ashanti Region, resistance to change by antenatal clinic workers from a policy of SP-IPT to IST would generally be low, and it would disappear amongst midwives if health outcomes for the mother and baby were improved by the new strategy. DCEs are a promising approach to identifying factors that will increase the likelihood of effective implementation of new interventions immediately after their efficacy has been proven. PMID:21886800

  18. The use of specialty training to retain doctors in Malawi: A discrete choice experiment.

    PubMed

    Mandeville, Kate L; Ulaya, Godwin; Lagarde, Mylène; Muula, Adamson S; Dzowela, Titha; Hanson, Kara

    2016-11-01

    Emigration has contributed to a shortage of doctors in many sub-Saharan African countries. Specialty training is highly valued by doctors and a potential tool for retention. Yet not all types of training may be valued equally. In the first study to examine preferences for postgraduate training in depth, we carried out a discrete choice experiment as part of a cross-sectional survey of all Malawian doctors within seven years of graduation and not yet in specialty training. Over August 2012 to March 2013, 148 doctors took part out of 153 eligible in Malawi. Despite evidence that specialty training is highly sought after, Malawian junior doctors would not accept all types of training. Doctors preferred timely training outside of Malawi in core specialties (internal medicine, general surgery, paediatrics, obstetrics & gynaecology). Specialty preferences are particularly strong, with most junior doctors requiring nearly double their monthly salary to accept training all in Malawi and over six-fold to accept training in ophthalmology (representing a bundle of unpopular but priority specialties). In contrast, the location of work before training did not significantly influence most doctors' choices when guaranteed specialty training. Using a latent class model, we identified four subgroups of junior doctors with distinct preferences. Policy simulations showed that these preferences could be leveraged by policymakers to improve retention in exchange for guaranteed specialty training, however incentivising the uptake of training in priority specialties will only be effective in those with more flexible preferences. These results indicate that indiscriminate expansion of postgraduate training to slow emigration of doctors from sub-Saharan African countries may not be effective unless doctors' preferences are taken into account. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  19. Discrete choice experiment produced estimates of acceptable risks of therapeutic options in cancer patients with febrile neutropenia.

    PubMed

    Sung, Lillian; Alibhai, Shabbir M; Ethier, Marie-Chantal; Teuffel, Oliver; Cheng, Sylvia; Fisman, David; Regier, Dean A

    2012-06-01

    To use a discrete choice experiment (DCE) to describe patient/proxy tolerance for the number of clinic visits, and chances of readmission, intensive care unit admission, and mortality to accept oral outpatient management of low-risk febrile neutropenia. Adults and children aged 12-18 years with cancer and parents of pediatric cancer patients were asked to choose between outpatient oral and inpatient intravenous management of low-risk febrile neutropenia. Using a DCE, we varied the attribute levels with the outpatient option and kept them constant for the inpatient option. Seventy-eight adults, 153 parents, and 43 children provided responses. All four attributes significantly affected choices. The mean tolerance (95% confidence interval) for the number of clinic visits per week was 3.6 (2.2-4.8), 2.1 (1.1-3.2), and 4.3 (2.5-6.0) to accept outpatient management among adults, parents, and children, respectively. With thrice weekly clinic visits and 7.5% chance of readmission, probabilities of accepting the outpatient strategy were 50% (44-54%) for adults, 43% (39-48%) for parents, and 53% (46-59%) for children. Using a DCE, we determined that a 7.5% chance of readmission and clinic visits more frequently than thrice weekly are unlikely to be acceptable. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. Using discrete choice experiments within a cost-benefit analysis framework: some considerations.

    PubMed

    McIntosh, Emma

    2006-01-01

    A great advantage of the stated preference discrete choice experiment (SPDCE) approach to economic evaluation methodology is its immense flexibility within applied cost-benefit analyses (CBAs). However, while the use of SPDCEs in healthcare has increased markedly in recent years there has been a distinct lack of equivalent CBAs in healthcare using such SPDCE-derived valuations. This article outlines specific issues and some practical suggestions for consideration relevant to the development of CBAs using SPDCE-derived benefits. The article shows that SPDCE-derived CBA can adopt recent developments in cost-effectiveness methodology including the cost-effectiveness plane, appropriate consideration of uncertainty, the net-benefit framework and probabilistic sensitivity analysis methods, while maintaining the theoretical advantage of the SPDCE approach. The concept of a cost-benefit plane is no different in principle to the cost-effectiveness plane and can be a useful tool for reporting and presenting the results of CBAs.However, there are many challenging issues to address for the advancement of CBA methodology using SPCDEs within healthcare. Particular areas for development include the importance of accounting for uncertainty in SPDCE-derived willingness-to-pay values, the methodology of SPDCEs in clinical trial settings and economic models, measurement issues pertinent to using SPDCEs specifically in healthcare, and the importance of issues such as consideration of the dynamic nature of healthcare and the resulting impact this has on the validity of attribute definitions and context.

  1. A systematic review of the reliability and validity of discrete choice experiments in valuing non-market environmental goods.

    PubMed

    Rakotonarivo, O Sarobidy; Schaafsma, Marije; Hockley, Neal

    2016-12-01

    While discrete choice experiments (DCEs) are increasingly used in the field of environmental valuation, they remain controversial because of their hypothetical nature and the contested reliability and validity of their results. We systematically reviewed evidence on the validity and reliability of environmental DCEs from the past thirteen years (Jan 2003-February 2016). 107 articles met our inclusion criteria. These studies provide limited and mixed evidence of the reliability and validity of DCE. Valuation results were susceptible to small changes in survey design in 45% of outcomes reporting reliability measures. DCE results were generally consistent with those of other stated preference techniques (convergent validity), but hypothetical bias was common. Evidence supporting theoretical validity (consistency with assumptions of rational choice theory) was limited. In content validity tests, 2-90% of respondents protested against a feature of the survey, and a considerable proportion found DCEs to be incomprehensible or inconsequential (17-40% and 10-62% respectively). DCE remains useful for non-market valuation, but its results should be used with caution. Given the sparse and inconclusive evidence base, we recommend that tests of reliability and validity are more routinely integrated into DCE studies and suggest how this might be achieved. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  2. Preference for practice: a Danish study on young doctors' choice of general practice using a discrete choice experiment.

    PubMed

    Pedersen, Line Bjørnskov; Gyrd-Hansen, Dorte

    2014-07-01

    This study examines the preferences of general practitioners (GPs) in training for organizational characteristics in general practice with focus on aspects that can mitigate problems with GP shortages. A discrete choice experiment was used to investigate preferences for the attributes practice type, number of GPs in general practice, collaboration with other practices, change in weekly working hours (administrative versus patient related), and change in yearly surplus. In May 2011, all doctors actively engaged in the family medicine program in Denmark were invited to participate in a web-based survey. A total of 485 GPs in training responded to the questionnaire, resulting in a response rate of 56%. A mixed logit model showed that GPs in training prefer to work in smaller shared practices (2 GPs). This stands in contrast to the preferences of current GPs. Hence, a generational change in the GP population is likely to introduce more productive practice forms, and problems with GP shortages are likely to be mitigated over the coming years. Results further showed that a majority of the respondents are willing to work in larger shared practices (with 3-4 GPs) if they receive an increase in surplus (approximately 50,000 DKK/6,719 EUR per year) and that they may be willing to take in more patient-related work if the increase in surplus is sufficient (approximately 200,000 DKK/26,875 EUR per year for 5 extra hours per week). Monetary incentives may therefore be an effective tool for further improving productivity.

  3. Modelling sheet-flow sediment transport in wave-bottom boundary layers using discrete-element modelling.

    PubMed

    Calantoni, Joseph; Holland, K Todd; Drake, Thomas G

    2004-09-15

    Sediment transport in oscillatory boundary layers is a process that drives coastal geomorphological change. Most formulae for bed-load transport in nearshore regions subsume the smallest-scale physics of the phenomena by parametrizing interactions amongst particles. In contrast, we directly simulate granular physics in the wave-bottom boundary layer using a discrete-element model comprised of a three-dimensional particle phase coupled to a one-dimensional fluid phase via Newton's third law through forces of buoyancy, drag and added mass. The particulate sediment phase is modelled using discrete particles formed to approximate natural grains by overlapping two spheres. Both the size of each sphere and the degree of overlap can be varied for these composite particles to generate a range of non-spherical grains. Simulations of particles having a range of shapes showed that the critical angle--the angle at which a grain pile will fail when tilted slowly from rest--increases from approximately 26 degrees for spherical particles to nearly 39 degrees for highly non-spherical composite particles having a dumbbell shape. Simulations of oscillatory sheet flow were conducted using composite particles with an angle of repose of approximately 33 degrees and a Corey shape factor greater than about 0.8, similar to the properties of beach sand. The results from the sheet-flow simulations with composite particles agreed more closely with laboratory measurements than similar simulations conducted using spherical particles. The findings suggest that particle shape may be an important factor for determining bed-load flux, particularly for larger bed slopes.

  4. How Combined Trip Purposes Are Associated with Transport Choice for Short Distance Trips. Results from a Cross-Sectional Study in the Netherlands

    PubMed Central

    Scheepers, Eline; Slinger, Minke; Wendel-Vos, Wanda; Schuit, Jantine

    2014-01-01

    Background One way to increase physical activity is to stimulate a shift from car use to walking or cycling. In single-purpose trips, purpose was found to be an important predictor of transport choice. However, as far as known, no studies have been conducted to see how trips with combined purposes affect this decision. This study was designed to provide insight into associations between combined purposes and transport choice. Methods An online questionnaire (N = 3,663) was used to collect data concerning transport choice for four primary purposes: shopping, going to public natural spaces, sports, and commuting. Per combination of primary trip purpose and transport choice, participants were asked to give examples of secondary purposes that they combine with the primary purpose. Logistic regression analyses were used to model the odds of both cycling and walking versus car use. Results Primary trip purposes combined with commuting, shopping, visiting private contacts or medical care were more likely to be made by car than by cycling or walking. Combinations with visiting catering facilities, trips to social infrastructure facilities, recreational outings, trips to facilities for the provision of daily requirements or private contacts during the trip were more likely to be made by walking and/or cycling than by car. Conclusion Combined trip purposes were found to be associated with transport choice. When stimulating active transport focus should be on the combined-trip purposes which were more likely to be made by car, namely trips combined with commuting, other shopping, visiting private contacts or medical care. PMID:25474653

  5. A Bayesian random effects discrete-choice model for resource selection: Population-level selection inference

    USGS Publications Warehouse

    Thomas, D.L.; Johnson, D.; Griffith, B.

    2006-01-01

    Bayesian hierarchical discrete-choice model for resource selection can provide managers with 2 components of population-level inference: average population selection and variability of selection. Both components are necessary to make sound management decisions based on animal selection.

  6. Patients' preferences in transplantation from marginal donors: results of a discrete choice experiment.

    PubMed

    Kamran, Sara; Conti, Filomena; Pomey, Marie-Pascale; Baron, Gabriel; Calmus, Yvon; Vidal-Trecan, Gwenaëlle

    2017-06-01

    To increase the donor pool, the strategy of transplantation from "marginal" donors was developed though patients' preferences about these donors were insufficiently known. The preferences of patients registered on the waiting list or already transplanted in eight transplant teams covering four main organs (i.e., kidney, liver, heart, and lung) were evaluated using the discrete choice experiment method. In each left during 2 days, patients were interviewed on four scenarios. Of 178 eligible patients, 167 were interviewed; 40% accepted marginal graft in their own situation and 89% at least in one of the scenarios. Imagining urgent situations or rare profiles with difficult access to transplantation, respectively, 86% and 71% accepted these grafts. Most (76%) preferred to be informed about these grafts and 43% preferred to be involved in decision. The emergency [OR = 1.24; 95% CI: (1.06-1.45)] and the hazardousness [OR = 0.88; 95% CI: (0.78-0.99)] of the transplantation were factors independently associated with marginal graft acceptance. Most patients preferred to be informed and to be involved in the decision. Marginal grafts could be more accepted by patients in critical medical situations or perceiving their situation as critical. Physicians' practices in transplantation should be reconsidered taking into account individual preferences. This study was performed in a single country and thus reflects the cultural bias and practice thereof. © 2017 Steunstichting ESOT.

  7. Rescaling quality of life values from discrete choice experiments for use as QALYs: a cautionary tale

    PubMed Central

    Flynn, Terry N; Louviere, Jordan J; Marley, Anthony AJ; Coast, Joanna; Peters, Tim J

    2008-01-01

    Background Researchers are increasingly investigating the potential for ordinal tasks such as ranking and discrete choice experiments to estimate QALY health state values. However, the assumptions of random utility theory, which underpin the statistical models used to provide these estimates, have received insufficient attention. In particular, the assumptions made about the decisions between living states and the death state are not satisfied, at least for some people. Estimated values are likely to be incorrectly anchored with respect to death (zero) in such circumstances. Methods Data from the Investigating Choice Experiments for the preferences of older people CAPability instrument (ICECAP) valuation exercise were analysed. The values (previously anchored to the worst possible state) were rescaled using an ordinal model proposed previously to estimate QALY-like values. Bootstrapping was conducted to vary artificially the proportion of people who conformed to the conventional random utility model underpinning the analyses. Results Only 26% of respondents conformed unequivocally to the assumptions of conventional random utility theory. At least 14% of respondents unequivocally violated the assumptions. Varying the relative proportions of conforming respondents in sensitivity analyses led to large changes in the estimated QALY values, particularly for lower-valued states. As a result these values could be either positive (considered to be better than death) or negative (considered to be worse than death). Conclusion Use of a statistical model such as conditional (multinomial) regression to anchor quality of life values from ordinal data to death is inappropriate in the presence of respondents who do not conform to the assumptions of conventional random utility theory. This is clearest when estimating values for that group of respondents observed in valuation samples who refuse to consider any living state to be worse than death: in such circumstances the model

  8. Young People’s Preferences for Family Planning Service Providers in Rural Malawi: A Discrete Choice Experiment

    PubMed Central

    Michaels-Igbokwe, Christine; Terris-Prestholt, Fern; Lagarde, Mylene; Chipeta, Effie; Cairns, John

    2015-01-01

    Objective To quantify the impact of service provider characteristics on young people’s choice of family planning (FP) service provider in rural Malawi in order to identify strategies for increasing access and uptake of FP among youth. Methods and Findings A discrete choice experiment was developed to assess the relative impact of service characteristics on preferences for FP service providers among young people (aged 15–24). Four alternative providers were included (government facility, private facility, outreach and community based distribution of FP) and described by six attributes (the distance between participants’ home and the service delivery point, frequency of service delivery, waiting time at the facility, service providers’ attitude, availability of FP commodities and price). A random parameters logit model was used to estimate preferences for service providers and the likely uptake of services following the expansion of outreach and community based distribution (CBDA) services. In the choice experiment young people were twice as likely to choose a friendly provider (government service odds ratio [OR] = 2.45, p<0.01; private service OR = 1.99, p<0.01; CBDA OR = 1.88, p<0.01) and more than two to three times more likely to choose a provider with an adequate supply of FP commodities (government service OR = 2.48, p<0.01; private service OR = 2.33, p<0.01; CBDA = 3.85, p<0.01). Uptake of community based services was greater than facility based services across a variety of simulated service scenarios indicating that such services may be an effective means of expanding access for youth in rural areas and an important tool for increasing service uptake among youth. Conclusions Ensuring that services are acceptable to young people may require additional training for service providers in order to ensure that all providers are friendly and non-judgemental when dealing with younger clients and to ensure that supplies are consistently available. PMID

  9. Understanding Health Workers’ Job Preferences to Improve Rural Retention in Timor-Leste: Findings from a Discrete Choice Experiment

    PubMed Central

    Smitz, Marc-Francois; Witter, Sophie; Lemiere, Christophe; Eozenou, Patrick Hoang-Vu; Lievens, Tomas; Zaman, Rashid U.; Engelhardt, Kay; Hou, Xiaohui

    2016-01-01

    Background Timor-Leste built its health workforce up from extremely low levels after its war of independence, with the assistance of Cuban training, but faces challenges as the first cohorts of doctors will shortly be freed from their contracts with government. Retaining doctors, nurses and midwives in remote areas requires a good understanding of health worker preferences. Methods The article reports on a discrete choice experiment (DCE) carried out amongst 441 health workers, including 173 doctors, 150 nurses and 118 midwives. Qualitative methods were conducted during the design phase. The attributes which emerged were wages, skills upgrading/specialisation, location, working conditions, transportation and housing. Findings One of the main findings of the study is the relative lack of importance of wages for doctors, which could be linked to high intrinsic motivation, perceptions of having an already highly paid job (relative to local conditions), and/or being in a relatively early stage of their career for most respondents. Professional development provides the highest satisfaction with jobs, followed by the working conditions. Doctors with less experience, males and the unmarried are more flexible about location. For nurses and midwives, skill upgrading emerged as the most cost effective method. Conclusions The study is the first of its kind conducted in Timor-Leste. It provides policy-relevant information to balance financial and non-financial incentives for different cadres and profiles of staff. It also augments a thin literature on the preferences of working doctors (as opposed to medical students) in low and middle income countries and provides insights into the ability to instil motivation to work in rural areas, which may be influenced by rural recruitment and Cuban-style training, with its emphasis on community service. PMID:27846242

  10. Exploring preferences for symptom management in primary care: a discrete choice experiment using a questionnaire survey.

    PubMed

    McAteer, Anne; Yi, Deokhee; Watson, Verity; Norwood, Patricia; Ryan, Mandy; Hannaford, Philip C; Elliott, Alison M

    2015-07-01

    Symptoms are important drivers for the use of primary care services. Strategies aimed at shifting the focus away from the GP have broadened the range of primary healthcare available. To explore preferences for managing symptoms and investigate trade-offs that the public are willing to make when deciding between different primary care services. UK-wide postal questionnaire survey of 1370 adults. A discrete choice experiment examined management preferences for three symptoms of differing seriousness (diarrhoea, dizziness, and chest pain). Willingness-to-pay estimates compared preferences between symptoms, and by sex, age, and income. Preferences differed significantly between symptoms. 'Self-care' was the preferred action for diarrhoea and 'consulting a GP' for dizziness and chest pain. 'Waiting time' and 'chance of a satisfactory outcome' were important factors for all three symptoms, although their relative importance differed. Broadly, people were more prepared to wait longer and less prepared to trade a good chance of a satisfactory outcome for symptoms rated as more serious. Generally, preferences within subgroups followed similar patterns as for the whole sample, although there were differences in the relative strength of preferences. Despite increased choices in primary care, 'traditional' actions of 'self-care' for minor symptoms and 'GP consultation' for more serious symptoms were preferred. The present findings suggest, however, that people may be willing to trade between different health services, particularly for less serious symptoms. Understanding the relative importance of different factors may help inform interventions aimed at changing management behaviour or improving services. © British Journal of General Practice 2015.

  11. Going Places, Making Choices: Transportation and the Environment. Curriculum Designed for Grades 9-12.

    ERIC Educational Resources Information Center

    National 4-H Council, Chevy Chase, MD.

    This curriculum packet includes a teacher's introduction and five curriculum units that explore how transportation needs affect the environment, including the quality of air and water, habitat, and global climate. These materials encourage teens to apply wisdom, ingenuity, and sound science to the choices they make. Units are: (1)…

  12. Acceptance of Vaccinations in Pandemic Outbreaks: A Discrete Choice Experiment

    PubMed Central

    Determann, Domino; Korfage, Ida J.; Lambooij, Mattijs S.; Bliemer, Michiel; Richardus, Jan Hendrik; Steyerberg, Ewout W.; de Bekker-Grob, Esther W.

    2014-01-01

    Background Preventive measures are essential to limit the spread of new viruses; their uptake is key to their success. However, the vaccination uptake in pandemic outbreaks is often low. We aim to elicit how disease and vaccination characteristics determine preferences of the general public for new pandemic vaccinations. Methods In an internet-based discrete choice experiment (DCE) a representative sample of 536 participants (49% participation rate) from the Dutch population was asked for their preference for vaccination programs in hypothetical communicable disease outbreaks. We used scenarios based on two disease characteristics (susceptibility to and severity of the disease) and five vaccination program characteristics (effectiveness, safety, advice regarding vaccination, media attention, and out-of-pocket costs). The DCE design was based on a literature review, expert interviews and focus group discussions. A panel latent class logit model was used to estimate which trade-offs individuals were willing to make. Results All above mentioned characteristics proved to influence respondents’ preferences for vaccination. Preference heterogeneity was substantial. Females who stated that they were never in favor of vaccination made different trade-offs than males who stated that they were (possibly) willing to get vaccinated. As expected, respondents preferred and were willing to pay more for more effective vaccines, especially if the outbreak was more serious (€6–€39 for a 10% more effective vaccine). Changes in effectiveness, out-of-pocket costs and in the body that advises the vaccine all substantially influenced the predicted uptake. Conclusions We conclude that various disease and vaccination program characteristics influence respondents’ preferences for pandemic vaccination programs. Agencies responsible for preventive measures during pandemics can use the knowledge that out-of-pocket costs and the way advice is given affect vaccination uptake to improve

  13. How Can the Health System Retain Women in HIV Treatment for a Lifetime? A Discrete Choice Experiment in Ethiopia and Mozambique

    PubMed Central

    Kruk, Margaret E.; Riley, Patricia L.; Palma, Anton M.; Adhikari, Sweta; Ahoua, Laurence; Arnaldo, Carlos; Belo, Dercio F.; Brusamento, Serena; Cumba, Luisa I. G.; Dziuban, Eric J.; El-Sadr, Wafaa M.; Gutema, Yoseph; Habtamu, Zelalem; Heller, Thomas; Kidanu, Aklilu; Langa, Judite; Mahagaja, Epifanio; McCarthy, Carey F.; Melaku, Zenebe; Shodell, Daniel; Tsiouris, Fatima; Young, Paul R.; Rabkin, Miriam

    2016-01-01

    Introduction Option B+, an approach that involves provision of antiretroviral therapy (ART) to all HIV-infected pregnant women for life, is the preferred strategy for prevention of mother to child transmission of HIV. Lifelong retention in care is essential to its success. We conducted a discrete choice experiment in Ethiopia and Mozambique to identify health system characteristics preferred by HIV-infected women to promote continuity of care. Methods Women living with HIV and receiving care at hospitals in Oromia Region, Ethiopia and Zambézia Province, Mozambique were shown nine choice cards and asked to select one of two hypothetical health facilities, each with six varying characteristics related to the delivery of HIV services for long term treatment. Mixed logit models were used to estimate the influence of six health service attributes on choice of clinics. Results 2,033 women participated in the study (response rate 97.8% in Ethiopia and 94.7% in Mozambique). Among the various attributes of structure and content of lifelong ART services, the most important attributes identified in both countries were respectful provider attitude and ability to obtain non-HIV health services during HIV-related visits. Availability of counseling support services was also a driver of choice. Facility type, i.e., hospital versus health center, was substantially less important. Conclusions Efforts to enhance retention in HIV care and treatment for pregnant women should focus on promoting respectful care by providers and integrating access to non-HIV health services in the same visit, as well as continuing to strengthen counseling. PMID:27551785

  14. Valuing QALYs in Relation to Equity Considerations Using a Discrete Choice Experiment.

    PubMed

    van de Wetering, Liesbet; van Exel, Job; Bobinac, Ana; Brouwer, Werner B F

    2015-12-01

    To judge whether an intervention offers value for money, the incremental costs per gained quality-adjusted life-year (QALY) need to be compared with some relevant threshold, which ideally reflects the monetary value of health gains. Literature suggests that this value may depend on the equity context in which health gains are produced, but the value of a QALY in relation to equity considerations has remained largely unexplored. The objective of this study was to estimate the social marginal willingness to pay (MWTP) for QALY gains in different equity subgroups, using a discrete choice experiment (DCE). Both severity of illness (operationalized as proportional shortfall) and fair innings (operationalized as age) were considered as grounds for differentiating the value of health gains. We obtained a sample of 1205 respondents, representative of the adult population of the Netherlands. The data was analysed using panel mixed multinomial logit (MMNL) and latent class models. The panel MMNL models showed counterintuitive results, with more severe health states reducing the probability of receiving treatment. The latent class models revealed distinct preference patterns in the data. MWTP per QALY was sensitive to severity of disease among a substantial proportion of the public, but not to the age of care recipients. These findings emphasize the importance of accounting for preference heterogeneity among the public on value-laden issues such as prioritizing health care, both in research and decision making. This study emphasises the need to further explore the monetary value of a QALY in relation to equity considerations.

  15. Allocating external financing for health: a discrete choice experiment of stakeholder preferences.

    PubMed

    Grépin, Karen A; Pinkstaff, Crossley B; Hole, Arne Risa; Henderson, Klara; Norheim, Ole Frithjof; Røttingen, John-Arne; Ottersen, Trygve

    2018-02-01

    Most donors of external financing for health use allocation policies to determine which countries are eligible to receive financial support and how much support each should receive. Currently, most of these policies place a great deal of weight on income per capita as a determinant of aid allocation but there is increasing interest in putting more weight on other country characteristics in the design of such policies. It is unclear, however, how much weight should be placed on other country characteristics. Using an online discrete choice experiment designed to elicit preferences over country characteristics to guide decisions about the allocation of external financing for health, we find that stakeholders assign a great deal of importance to health inequalities and the burden of disease but put very little weight on income per capita. We also find considerable variation in preferences across stakeholders, with people from low- and middle-income countries putting more weight on the burden of disease and people from high-income countries putting more weight on health inequalities. These findings suggest that stakeholders put more weight on burden of disease and health inequalities than on income per capita in evaluating which countries should received external financing for health and that that people living in aid recipient may have different preferences than people living in donor countries. Donors may wish to take these differences in preferences in mind if they are reconsidering their aid allocation policies. © The Author(s) 2018. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. 5 CFR 572.102 - Agency discretion.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... TRANSPORTATION EXPENSES; NEW APPOINTEES AND INTERVIEWS § 572.102 Agency discretion. Payment of travel expenses... and transportation or interview expenses in filling any position, the agency should consider such factors as availability of funds as well as the desirability of conducting interviews for a particular job...

  17. A discrete choice experiment investigating preferences for funding drugs used to treat orphan diseases: an exploratory study.

    PubMed

    Mentzakis, Emmanouil; Stefanowska, Patricia; Hurley, Jeremiah

    2011-07-01

    Policy debate about funding criteria for drugs used to treat rare, orphan diseases is gaining prominence. This study presents evidence from a discrete choice experiment using a convenience sample of university students to investigate individual preferences regarding public funding for drugs used to treat rare diseases and common diseases. This pilot study finds that: other things equal, the respondents do not prefer to have the government spend more for drugs used to treat rare diseases; that respondents are not willing to pay more per life year gained for a rare disease than a common disease; and that respondents weigh relevant attributes of the coverage decisions (e.g. costs, disease severity and treatment effectiveness) similarly for both rare and common diseases. The results confirm the importance of severity and treatment effectiveness in preferences for public funding. Although this is the first study of its kind, the results send a cautionary message regarding the special treatment of orphan drugs in coverage decision-making.

  18. Generalized Reduction Formula for Discrete Wigner Functions of Multiqubit Systems

    NASA Astrophysics Data System (ADS)

    Srinivasan, K.; Raghavan, G.

    2018-03-01

    Density matrices and Discrete Wigner Functions are equally valid representations of multiqubit quantum states. For density matrices, the partial trace operation is used to obtain the quantum state of subsystems, but an analogous prescription is not available for discrete Wigner Functions. Further, the discrete Wigner function corresponding to a density matrix is not unique but depends on the choice of the quantum net used for its reconstruction. In the present work, we derive a reduction formula for discrete Wigner functions of a general multiqubit state which works for arbitrary quantum nets. These results would be useful for the analysis and classification of entangled states and the study of decoherence purely in a discrete phase space setting and also in applications to quantum computing.

  19. Adolescent values for immunisation programs in Australia: A discrete choice experiment.

    PubMed

    Wang, Bing; Chen, Gang; Ratcliffe, Julie; Afzali, Hossein Haji Ali; Giles, Lynne; Marshall, Helen

    2017-01-01

    The importance of adolescent engagement in health decisions and public health programs such as immunisation is becoming increasingly recognised. Understanding adolescent preferences and further identifying barriers and facilitators for immunisation acceptance is critical to the success of adolescent immunisation programs. This study applied a discrete choice experiment (DCE) to assess vaccination preferences in adolescents. This study was conducted as a cross-sectional, national online survey in Australian adolescents. The DCE survey evaluated adolescent vaccination preferences. Six attributes were assessed including disease severity, target for protection, price, location of vaccination provision, potential side effects and vaccine delivery method. A mixed logit model was used to analyse DCE data. This survey was conducted between December 2014 and January 2015. Of 800 adolescents aged 15 to 19 years, stronger preferences were observed overall for: vaccination in the case of a life threatening illness (p<0.001), lower price vaccinations (p<0.001), mild but common side effects (p = 0.004), delivery via a skin patch (p<0.001) and being administered by a family practitioner (p<0.001). Participants suggested that they and their families would be willing to pay AU$394.28 (95%CI: AU$348.40 to AU$446.92) more for a vaccine targeting a life threatening illness than a mild-moderate illness, AU$37.94 (95%CI: AU$19.22 to AU$57.39) more for being vaccinated at a family practitioner clinic than a council immunisation clinic, AU$23.01 (95%CI: AU$7.12 to AU$39.24) more for common but mild and resolving side effects compared to rare but serious side effects, and AU$51.80 (95%CI: AU$30.42 to AU$73.70) more for delivery via a skin patch than injection. Consideration of adolescent preferences may result in improved acceptance of, engagement in and uptake of immunisation programs targeted for this age group.

  20. Acceptability of Financial Incentives for Health Behaviours: A Discrete Choice Experiment.

    PubMed

    Giles, Emma L; Becker, Frauke; Ternent, Laura; Sniehotta, Falko F; McColl, Elaine; Adams, Jean

    2016-01-01

    Healthy behaviours are important determinants of health and disease, but many people find it difficult to perform these behaviours. Systematic reviews support the use of personal financial incentives to encourage healthy behaviours. There is concern that financial incentives may be unacceptable to the public, those delivering services and policymakers, but this has been poorly studied. Without widespread acceptability, financial incentives are unlikely to be widely implemented. We sought to answer two questions: what are the relative preferences of UK adults for attributes of financial incentives for healthy behaviours? Do preferences vary according to the respondents' socio-demographic characteristics? We conducted an online discrete choice experiment. Participants were adult members of a market research panel living in the UK selected using quota sampling. Preferences were examined for financial incentives for: smoking cessation, regular physical activity, attendance for vaccination, and attendance for screening. Attributes of interest (and their levels) were: type of incentive (none, cash, shopping vouchers or lottery tickets); value of incentive (a continuous variable); schedule of incentive (same value each week, or value increases as behaviour change is sustained); other information provided (none, written information, face-to-face discussion, or both); and recipients (all eligible individuals, people living in low-income households, or pregnant women). Cash or shopping voucher incentives were preferred as much as, or more than, no incentive in all cases. Lower value incentives and those offered to all eligible individuals were preferred. Preferences for additional information provided alongside incentives varied between behaviours. Younger participants and men were more likely to prefer incentives. There were no clear differences in preference according to educational attainment. Cash or shopping voucher-type financial incentives for healthy behaviours are

  1. What do women want? Valuing women's preferences and estimating demand for alternative models of maternity care using a discrete choice experiment.

    PubMed

    Fawsitt, Christopher G; Bourke, Jane; Greene, Richard A; McElroy, Brendan; Krucien, Nicolas; Murphy, Rosemary; Lutomski, Jennifer E

    2017-11-01

    In many countries, there has been a considerable shift towards providing a more woman-centred maternity service, which affords greater consumer choice. Maternity service provision in Ireland is set to follow this trend with policymakers committed to improving maternal choice at hospital level. However, women's preferences for maternity care are unknown, as is the expected demand for new services. In this paper, we used a discrete choice experiment (DCE) to (1) investigate women's strengths of preference for different features of maternity care; (2) predict market uptake for consultant- and midwifery-led care, and a hybrid model of care called the Domiciliary In and Out of Hospital Care scheme; and (3) calculate the welfare change arising from the provision of these services. Women attending antenatal care across two teaching hospitals in Ireland were invited to participate in the study. Women's preferred model of care resembled the hybrid model of care, with considerably more women expected to utilise this service than either consultant- or midwifery-led care. The benefit of providing all three services proved considerably greater than the benefit of providing two or fewer services. From a priority setting perspective, pursuing all three models of care would generate a considerable welfare gain, although the cost-effectiveness of such an approach needs to be considered. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  2. Is Best-Worst Scaling Suitable for Health State Valuation? A Comparison with Discrete Choice Experiments.

    PubMed

    Krucien, Nicolas; Watson, Verity; Ryan, Mandy

    2017-12-01

    Health utility indices (HUIs) are widely used in economic evaluation. The best-worst scaling (BWS) method is being used to value dimensions of HUIs. However, little is known about the properties of this method. This paper investigates the validity of the BWS method to develop HUI, comparing it to another ordinal valuation method, the discrete choice experiment (DCE). Using a parametric approach, we find a low level of concordance between the two methods, with evidence of preference reversals. BWS responses are subject to decision biases, with significant effects on individuals' preferences. Non parametric tests indicate that BWS data has lower stability, monotonicity and continuity compared to DCE data, suggesting that the BWS provides lower quality data. As a consequence, for both theoretical and technical reasons, practitioners should be cautious both about using the BWS method to measure health-related preferences, and using HUI based on BWS data. Given existing evidence, it seems that the DCE method is a better method, at least because its limitations (and measurement properties) have been extensively researched. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  3. Choice of electricity provider in California after deregulation

    NASA Astrophysics Data System (ADS)

    Keanini, Rasa Ilze

    Surveys often ask consumers how much they are willing to pay for certain goods and services, without requiring the consumer to actually pay for the good or service. Such surveys, termed stated preference studies, find that consumers value renewable electricity. This result is in contrast to actual experiences in recently deregulated electricity markets in several states, including California. When given the opportunity to choose in California, only one to two percent of the population opted for renewable electricity products. This dissertation used data from residential customers who chose an alternative electricity product in California's deregulated electricity market to determine the value placed on the renewable attribute of electricity products. This dissertation begins by taking a historical look at the electricity market of the nation and specifically California. From 1998 through 2001, California's electricity market was deregulated to include retail competition. This dissertation used data from electric service providers to reveal the factors influencing residential customer's choice of electricity product. Discrete choice models were used to determine the factors influencing electricity product choice. The results indicated that both price and renewable content had an effect on choice of product. Additionally, a more complicated model jointly estimating the discrete choice of electricity product with the continuous choice of electricity consumption (kWh) was specified and estimated.

  4. The effect of including an opt-out option in discrete choice experiments.

    PubMed

    Veldwijk, Jorien; Lambooij, Mattijs S; de Bekker-Grob, Esther W; Smit, Henriëtte A; de Wit, G Ardine

    2014-01-01

    to determine to what extent the inclusion of an opt-out option in a DCE may have an effect on choice behaviour and therefore might influence the attribute level estimates, the relative importance of the attributes and calculated trade-offs. 781 Dutch Type 2 Diabetes Mellitus patients completed a questionnaire containing nine choice tasks with an opt-out option and nice forced choice tasks. Mixed-logit models were used to estimate the relative importance of the five lifestyle program related attributes that were included. Willingness to pay (WTP) values were calculated and it was tested whether results differed between respondents who answered the choice tasks with an opt-out option in the first or second part of the questionnaire. 21.4% of the respondents always opted out. Respondents who were given the opt-out option in the first part of the questionnaire as well as lower educated respondents significantly more often opted out. For both the forced and unforced choice model, different attributes showed significant estimates, the relative importance of the attributes was equal. However, due to differences in relative importance weights, the WTP values for the PA schedule differed significantly between both datasets. Results show differences in opting out based on the location of the opt-out option and respondents' educational level; this resulted in small differences between the forced and unforced choice model. Since respondents seem to learn from answering forced choice tasks, a dual response design might result in higher data quality compared to offering a direct opt-out option. Future research should empirically explore how choice sets should be presented to make them as easy and less complex as possible in order to reduce the proportion of respondents that opts-out due to choice task complexity. Moreover, future research should debrief respondents to examine the reasons for choosing the opt-out alternative.

  5. An implementation of discrete electron transport models for gold in the Geant4 simulation toolkit

    NASA Astrophysics Data System (ADS)

    Sakata, D.; Incerti, S.; Bordage, M. C.; Lampe, N.; Okada, S.; Emfietzoglou, D.; Kyriakou, I.; Murakami, K.; Sasaki, T.; Tran, H.; Guatelli, S.; Ivantchenko, V. N.

    2016-12-01

    Gold nanoparticle (GNP) boosted radiation therapy can enhance the biological effectiveness of radiation treatments by increasing the quantity of direct and indirect radiation-induced cellular damage. As the physical effects of GNP boosted radiotherapy occur across energy scales that descend down to 10 eV, Monte Carlo simulations require discrete physics models down to these very low energies in order to avoid underestimating the absorbed dose and secondary particle generation. Discrete physics models for electron transportation down to 10 eV have been implemented within the Geant4-DNA low energy extension of Geant4. Such models allow the investigation of GNP effects at the nanoscale. At low energies, the new models have better agreement with experimental data on the backscattering coefficient, and they show similar performance for transmission coefficient data as the Livermore and Penelope models already implemented in Geant4. These new models are applicable in simulations focussed towards estimating the relative biological effectiveness of radiation in GNP boosted radiotherapy applications with photon and electron radiation sources.

  6. Discontinuous finite volume element discretization for coupled flow-transport problems arising in models of sedimentation

    NASA Astrophysics Data System (ADS)

    Bürger, Raimund; Kumar, Sarvesh; Ruiz-Baier, Ricardo

    2015-10-01

    The sedimentation-consolidation and flow processes of a mixture of small particles dispersed in a viscous fluid at low Reynolds numbers can be described by a nonlinear transport equation for the solids concentration coupled with the Stokes problem written in terms of the mixture flow velocity and the pressure field. Here both the viscosity and the forcing term depend on the local solids concentration. A semi-discrete discontinuous finite volume element (DFVE) scheme is proposed for this model. The numerical method is constructed on a baseline finite element family of linear discontinuous elements for the approximation of velocity components and concentration field, whereas the pressure is approximated by piecewise constant elements. The unique solvability of both the nonlinear continuous problem and the semi-discrete DFVE scheme is discussed, and optimal convergence estimates in several spatial norms are derived. Properties of the model and the predicted space accuracy of the proposed formulation are illustrated by detailed numerical examples, including flows under gravity with changing direction, a secondary settling tank in an axisymmetric setting, and batch sedimentation in a tilted cylindrical vessel.

  7. Applications of algebraic topology to compatible spatial discretizations.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bochev, Pavel Blagoveston; Hyman, James M.

    We provide a common framework for compatible discretizations using algebraic topology to guide our analysis. The main concept is the natural inner product on cochains, which induces a combinatorial Hodge theory. The framework comprises of mutually consistent operations of differentiation and integration, has a discrete Stokes theorem, and preserves the invariants of the DeRham cohomology groups. The latter allows for an elementary calculation of the kernel of the discrete Laplacian. Our framework provides an abstraction that includes examples of compatible finite element, finite volume and finite difference methods. We describe how these methods result from the choice of a reconstructionmore » operator and when they are equivalent.« less

  8. Evaluation of strategies to communicate harmful and potentially harmful constituent (HPHC) information through cigarette package inserts: a discrete choice experiment.

    PubMed

    Salloum, Ramzi G; Louviere, Jordan J; Getz, Kayla R; Islam, Farahnaz; Anshari, Dien; Cho, Yoojin; O'Connor, Richard J; Hammond, David; Thrasher, James F

    2017-07-13

    The US Food and Drug Administration (FDA) has regulatory authority to use inserts to communicate with consumers about harmful and potentially harmful constituents (HPHCs) in tobacco products; however, little is known about the most effective manner for presenting HPHC information. In a discrete choice experiment, participants evaluated eight choice sets, each of which showed two cigarette packages from four different brands and tar levels (high vs low), accompanied by an insert that included between-subject manipulations (ie, listing of HPHCs vs grouping by disease outcome and numeric values ascribed to HPHCs vs no numbers) and within-subject manipulations (ie, 1 of 4 warning topics; statement linking an HPHC with disease vs statement with no HPHC link). For each choice set, participants were asked: (1) which package is more harmful and (2) which motivates them to not smoke; each with a 'no difference' option. Alternative-specific logit models regressed choice on attribute levels. 1212 participants were recruited from an online consumer panel (725 18-29-year-old smokers and susceptible non-smokers and 487 30-64-year-old smokers). Participants were more likely to endorse high-tar products as more harmful than low-tar products, with a greater effect when numeric HPHC information was present. Compared with a simple warning statement, the statement linking HPHCs with disease encouraged quit motivation. Numeric HPHC information on inserts appears to produce misunderstandings that some cigarettes are less harmful than others. Furthermore, brief narratives that link HPHCs to smoking-related disease may promote cessation versus communications that do not explicitly link HPHCs to disease. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  9. Assessing user preferences for sexually transmitted infection testing services: a discrete choice experiment

    PubMed Central

    Llewellyn, Carrie; Pollard, Alex; Lagarde, Mylene; Richardson, Daniel; Cairns, John; Fisher, Martin; Smith, Helen

    2012-01-01

    Objective To assess user preferences for different aspects of sexually transmitted infection (STI) testing services. Design A discrete choice experiment. Setting 14 centres offering tests for STIs in East Sussex, England. Participants People testing for STIs. Main outcome measure (Adjusted) ORs in relation to preferred service characteristics. Results 3358 questionnaires were returned; mean age 26 (SD 9.4) years. 70% (2366) were recruited from genitourinary medicine (GUM) clinics. The analysis suggested that the most important characteristics to users were whether ‘staff had specialist STI knowledge’ compared with ‘staff without it’ (OR 2.55; 95% CI 2.47 to 2.63) and whether ‘tests for all STIs’ were offered rather than ‘some’ (OR 2.19; 95% CI 2.12 to 2.25). They remained the most important two service characteristics despite stratifying the analysis by variables such as age and sex. Staff levels of expertise were viewed as particularly important by people attending CASH centres, women and non-men who have sex with men. A ‘text or call to a mobile phone’ and ‘dropping in and waiting’ were generally the preferred methods of results reporting and appointment system, respectively. Conclusions This study suggests that people testing for STIs place particular importance on testing for all infections rather than some and staff with specialist STI knowledge. Thus, targets based purely on waiting up to 48 h for an appointment are misguided from a user perspective. PMID:22661632

  10. Discrete choice modeling of shovelnose sturgeon habitat selection in the Lower Missouri River

    USGS Publications Warehouse

    Bonnot, T.W.; Wildhaber, M.L.; Millspaugh, J.J.; DeLonay, A.J.; Jacobson, R.B.; Bryan, J.L.

    2011-01-01

    Substantive changes to physical habitat in the Lower Missouri River, resulting from intensive management, have been implicated in the decline of pallid (Scaphirhynchus albus) and shovelnose (S. platorynchus) sturgeon. To aid in habitat rehabilitation efforts, we evaluated habitat selection of gravid, female shovelnose sturgeon during the spawning season in two sections (lower and upper) of the Lower Missouri River in 2005 and in the upper section in 2007. We fit discrete choice models within an information theoretic framework to identify selection of means and variability in three components of physical habitat. Characterizing habitat within divisions around fish better explained selection than habitat values at the fish locations. In general, female shovelnose sturgeon were negatively associated with mean velocity between them and the bank and positively associated with variability in surrounding depths. For example, in the upper section in 2005, a 0.5 m s-1 decrease in velocity within 10 m in the bank direction increased the relative probability of selection 70%. In the upper section fish also selected sites with surrounding structure in depth (e.g., change in relief). Differences in models between sections and years, which are reinforced by validation rates, suggest that changes in habitat due to geomorphology, hydrology, and their interactions over time need to be addressed when evaluating habitat selection. Because of the importance of variability in surrounding depths, these results support an emphasis on restoring channel complexity as an objective of habitat restoration for shovelnose sturgeon in the Lower Missouri River.

  11. Societal preferences for distributive justice in the allocation of health care resources: a latent class discrete choice experiment.

    PubMed

    Skedgel, Chris; Wailoo, Allan; Akehurst, Ron

    2015-01-01

    Economic theory suggests that resources should be allocated in a way that produces the greatest outputs, on the grounds that maximizing output allows for a redistribution that could benefit everyone. In health care, this is known as QALY (quality-adjusted life-year) maximization. This justification for QALY maximization may not hold, though, as it is difficult to reallocate health. Therefore, the allocation of health care should be seen as a matter of distributive justice as well as efficiency. A discrete choice experiment was undertaken to test consistency with the principles of QALY maximization and to quantify the willingness to trade life-year gains for distributive justice. An empirical ethics process was used to identify attributes that appeared relevant and ethically justified: patient age, severity (decomposed into initial quality and life expectancy), final health state, duration of benefit, and distributional concerns. Only 3% of respondents maximized QALYs with every choice, but scenarios with larger aggregate QALY gains were chosen more often and a majority of respondents maximized QALYs in a majority of their choices. However, respondents also appeared willing to prioritize smaller gains to preferred groups over larger gains to less preferred groups. Marginal analyses found a statistically significant preference for younger patients and a wider distribution of gains, as well as an aversion to patients with the shortest life expectancy or a poor final health state. These results support the existence of an equity-efficiency tradeoff and suggest that well-being could be enhanced by giving priority to programs that best satisfy societal preferences. Societal preferences could be incorporated through the use of explicit equity weights, although more research is required before such weights can be used in priority setting. © The Author(s) 2014.

  12. Patient preferences for healthcare delivery through community pharmacy settings in the USA: A discrete choice study.

    PubMed

    Feehan, M; Walsh, M; Godin, J; Sundwall, D; Munger, M A

    2017-12-01

    In order to improve public health, it is necessary to facilitate patients' easy access to affordable high-quality primary health care, and one enhanced approach to do so may be to provide primary healthcare services in the community pharmacy setting. Discrete choice experiments to evaluate patient demand for services in pharmacy are relatively limited and have been hampered by a focus on only a few service alternatives, most focusing on changes in more traditional pharmacy services. The study aim was to gauge patient preferences explicitly for primary healthcare services that could be delivered through community pharmacy settings in the USA, using a very large sample to accommodate multiple service delivery options. An online survey was administered to a total of 9202 adult patients from the general population. A subsequent online survey was administered to 50 payer reimbursement decision-makers. The patient survey included a discrete choice experiment (DCE) which showed competing scenarios describing primary care service offerings. The respondents chose which scenario would be most likely to induce them to switch from their current pharmacy, and an optimal patient primary care service model was derived. The likelihood this model would be reimbursed was then determined in the payer survey. The final optimal service configuration that would maximize patient preference included the pharmacy: offering appointments to see a healthcare provider in the pharmacy, having access to their full medical record, provide point-of-care diagnostic testing, offer health preventive screening, provide limited physical examinations such as measuring vital signs, and drug prescribing in the pharmacy. The optimal model had the pharmacist as the provider; however, little change in demand was evident if the provider was a nurse-practitioner or physician's assistant. The demand for this optimal model was 2-fold higher (25.5%; 95% Bayesian precision interval (BPI) 23.5%-27.0%) than for a

  13. The Effect of Including an Opt-Out Option in Discrete Choice Experiments

    PubMed Central

    Veldwijk, Jorien; Lambooij, Mattijs S.; de Bekker-Grob, Esther W.; Smit, Henriëtte A.; de Wit, G. Ardine

    2014-01-01

    Objective to determine to what extent the inclusion of an opt-out option in a DCE may have an effect on choice behaviour and therefore might influence the attribute level estimates, the relative importance of the attributes and calculated trade-offs. Methods 781 Dutch Type 2 Diabetes Mellitus patients completed a questionnaire containing nine choice tasks with an opt-out option and nice forced choice tasks. Mixed-logit models were used to estimate the relative importance of the five lifestyle program related attributes that were included. Willingness to pay (WTP) values were calculated and it was tested whether results differed between respondents who answered the choice tasks with an opt-out option in the first or second part of the questionnaire. Results 21.4% of the respondents always opted out. Respondents who were given the opt-out option in the first part of the questionnaire as well as lower educated respondents significantly more often opted out. For both the forced and unforced choice model, different attributes showed significant estimates, the relative importance of the attributes was equal. However, due to differences in relative importance weights, the WTP values for the PA schedule differed significantly between both datasets. Conclusions Results show differences in opting out based on the location of the opt-out option and respondents' educational level; this resulted in small differences between the forced and unforced choice model. Since respondents seem to learn from answering forced choice tasks, a dual response design might result in higher data quality compared to offering a direct opt-out option. Future research should empirically explore how choice sets should be presented to make them as easy and less complex as possible in order to reduce the proportion of respondents that opts-out due to choice task complexity. Moreover, future research should debrief respondents to examine the reasons for choosing the opt-out alternative. PMID:25365169

  14. Consumer preference for dinoprostone vaginal gel using stated preference discrete choice modelling.

    PubMed

    Taylor, Susan; Armour, Carol

    2003-01-01

    To assess consumer preference for two methods of induction of labour using stated preference discrete choice modelling. The methods of induction were artificial rupture of the membranes (ARM) plus oxytocin and dinoprostone (prostaglandin E(2)) vaginal gel, followed by oxytocin if necessary. Consumer preference was measured in terms of willingness to pay for each of the attributes. These attributes were the method of administration, place of care, length of time from induction to delivery, need for epidural anaesthetic, type of delivery and cost. Levels were assigned to each of the attributes. Pregnant women attending a public hospital antenatal clinic were asked to read a description of the two methods and then to choose between them in 18 different scenarios in which the levels of the attributes were varied. Women were willing to pay 11 Australian dollars for a 1% reduction in the chance of needing oxytocin as well as the gel and 55 Australian dollars for every 1 hour reduction in the length of time from induction to delivery. For a 1% reduction in the chance of needing an epidural anaesthetic or Caesarean section, women expressed a willingness to pay of 20 Australian dollars and 90 Australian dollars, respectively. All estimates were obtained in 1998 and expressed in Australian dollars (1 Australian dollar = 0.63 US dollars). Women valued the less invasive method of administration of the gel and the associated greater freedom of movement during labour. However, they valued the shorter time from induction to delivery associated with ARM plus oxytocin more highly. A policy which allows women access to the gel for up to two doses would accommodate this consumer preference.

  15. Development of discrete choice model considering internal reference points and their effects in travel mode choice context

    NASA Astrophysics Data System (ADS)

    Sarif; Kurauchi, Shinya; Yoshii, Toshio

    2017-06-01

    In the conventional travel behavior models such as logit and probit, decision makers are assumed to conduct the absolute evaluations on the attributes of the choice alternatives. On the other hand, many researchers in cognitive psychology and marketing science have been suggesting that the perceptions of attributes are characterized by the benchmark called “reference points” and the relative evaluations based on them are often employed in various choice situations. Therefore, this study developed a travel behavior model based on the mental accounting theory in which the internal reference points are explicitly considered. A questionnaire survey about the shopping trip to the CBD in Matsuyama city was conducted, and then the roles of reference points in travel mode choice contexts were investigated. The result showed that the goodness-of-fit of the developed model was higher than that of the conventional model, indicating that the internal reference points might play the major roles in the choice of travel mode. Also shown was that the respondents seem to utilize various reference points: some tend to adopt the lowest fuel price they have experienced, others employ fare price they feel in perceptions of the travel cost.

  16. Video or In-Clinic Consultation? Selection of Attributes as Preparation for a Discrete Choice Experiment Among Key Stakeholders.

    PubMed

    Chudner, Irit; Goldfracht, Margalit; Goldblatt, Hadass; Drach-Zahavy, Anat; Karkabi, Khaled

    2018-06-09

    Video consultations (VCs) provide increased accessibility of primary care to remote areas and overall improved care for chronic patients. They also contribute to higher patient satisfaction and improved resource management. Despite these benefits, VC integration into the health system is complex and slow. Understanding the VC-related preferences of three key stakeholders-patients, primary care physicians (PCPs) and policy makers (PMs)-is crucial for achieving optimal implementation. The aim of this study was to select relevant attributes and levels for a discrete choice experiment (DCE) of stakeholders' choice-VC or traditional in-clinic consultation (I-CC) in primary care. Ten semi-structured focus group interviews and 24 semi-structured individual interviews were conducted. Data analysis was performed inductively, using a thematic content analysis method. An attribute-ranking exercise was then conducted based on the results gleaned from the interviews. The most important attributes when choosing either VC or I-CC, for both patients and PMs, were: (1) time to next available appointment; (2) time in line before consultation; (3) relationship to PCP; and (4) quality of consultation. For PCPs, the most important attributes were: (1) time in line before consultation; (2) patient's self-management ability; (3) consultation purpose; (4) quality of consultation. This qualitative study identified attributes and levels for a DCE quantitative stage among three key stakeholder groups. It adds to the literature of examples of developing DCE attributes, and to literature about the stakeholder benefits in the area of telemedicine in healthcare.

  17. Some unsolved problems in discrete mathematics and mathematical cybernetics

    NASA Astrophysics Data System (ADS)

    Korshunov, Aleksei D.

    2009-10-01

    There are many unsolved problems in discrete mathematics and mathematical cybernetics. Writing a comprehensive survey of such problems involves great difficulties. First, such problems are rather numerous and varied. Second, they greatly differ from each other in degree of completeness of their solution. Therefore, even a comprehensive survey should not attempt to cover the whole variety of such problems; only the most important and significant problems should be reviewed. An impersonal choice of problems to include is quite hard. This paper includes 13 unsolved problems related to combinatorial mathematics and computational complexity theory. The problems selected give an indication of the author's studies for 50 years; for this reason, the choice of the problems reviewed here is, to some extent, subjective. At the same time, these problems are very difficult and quite important for discrete mathematics and mathematical cybernetics. Bibliography: 74 items.

  18. Conducting a Discrete-Choice Experiment Study Following Recommendations for Good Research Practices: An Application for Eliciting Patient Preferences for Diabetes Treatments.

    PubMed

    Janssen, Ellen M; Hauber, A Brett; Bridges, John F P

    2018-01-01

    To consolidate and illustrate good research practices in health care to the application and reporting of a study measuring patient preferences for type 2 diabetes mellitus medications, given recent methodological advances in stated-preference methods. The International Society for Pharmacoeconomics and Outcomes Research good research practices and other recommendations were used to conduct a discrete-choice experiment. Members of a US online panel with type 2 diabetes mellitus completed a Web-enabled, self-administered survey that elicited choices between treatment pairs with six attributes at three possible levels each. A D-efficient experimental design blocked 48 choice tasks into three 16-task surveys. Preference estimates were obtained using mixed logit estimation and were used to calculate choice probabilities. A total of 552 participants (51% males) completed the survey. Avoiding 90 minutes of nausea was valued the highest (mean -10.00; 95% confidence interval [CI] -10.53 to -9.47). Participants wanted to avoid low blood glucose during the day and/or night (mean -3.87; 95% CI -4.32 to -3.42) or one pill and one injection per day (mean -7.04; 95% CI -7.63 to -6.45). Participants preferred stable blood glucose 6 d/wk (mean 4.63; 95% CI 4.15 to 5.12) and a 1% decrease in glycated hemoglobin (mean 5.74; 95% CI 5.22 to 6.25). If cost increased by $1, the probability that a treatment profile would be chosen decreased by 1%. These results are consistent with the idea that people have strong preferences for immediate consequences of medication. Despite efforts to produce recommendations, ambiguity surrounding good practices remains and various judgments need to be made when conducting stated-preference studies. To ensure transparency, these judgments should be described and justified. Copyright © 2018 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  19. Transport choice when travelling to a sports facility: the role of perceived route features - Results from a cross-sectional study in the Netherlands.

    PubMed

    de Hollander, Ellen L; Scheepers, Eline; van Wijnen, Harm J; van Wesemael, Pieter Jv; Schuit, Albertine J; Wendel-Vos, Wanda; van Kempen, Elise Emm

    2015-01-01

    Physical activity and sedentary behaviour are independently associated with health outcomes, where physical activity (PA) is associated with health benefits and sedentary behaviour is associated with health risks. One possible strategy to counteract sedentary behaviour is to stimulate active transport use. As monitoring studies in the Netherlands have shown that among sedentary people the proportion of adults who engage in sports (hereafter: sports practitioners) is 62.3%, sports practitioners seem a feasible target group for this strategy. Previous studies have generally reported associations between neighbourhood characteristics and active transport use. However, the neighbourhood covers only part of the route to a certain destination. Therefore, we examined the association between perceived route features and transport choice when travelling up to 7.5 kilometres to a sports facility among sports practitioners. For 1118 Dutch sports practitioners - who indicated that they practice a sport and travel to a sports facility - age 18 and older, data on transport choice and perceived features of the route to a sports facility were gathered. Participants were classified into one of three transport groups based on their transport choice: car users, cyclists and walkers. Participants were asked whether perceived route features influenced their transport choice. Logistic regression was used to model the odds of cycling versus car use and walking versus car use in the association with perceived route features, adjusted for potential confounders. Perceived traffic safety was associated with lower odds of cycling (OR: 0.36, 95% CI: 0.15-0.86). Perceived route duration was associated with lower odds of both cycling (OR: 0.54, 95%CI: 0.39-0.75) and walking (OR: 0.60, 95%CI: 0.36-1.00). Perceived distance to a sports facility and having to make a detour when using other transport modes than the chosen transport mode were associated with higher odds of both cycling and walking

  20. Prioritising patients for bariatric surgery: building public preferences from a discrete choice experiment into public policy

    PubMed Central

    Whitty, Jennifer A; Ratcliffe, Julie; Kendall, Elizabeth; Burton, Paul; Wilson, Andrew; Littlejohns, Peter; Harris, Paul; Krinks, Rachael; Scuffham, Paul A

    2015-01-01

    Objectives To derive priority weights for access to bariatric surgery for obese adults, from the perspective of the public. Setting Australian public hospital system. Participants Adults (N=1994), reflecting the age and gender distribution of Queensland and South Australia. Primary and secondary outcome measures A discrete choice experiment in which respondents indicated which of two individuals with different characteristics should be prioritised for surgery in repeated hypothetical choices. Potential surgery recipients were described by seven key characteristics or attributes: body mass index (BMI), presence of comorbid conditions, age, family history, commitment to lifestyle change, time on the surgical wait list and chance of maintaining weight loss following surgery. A multinomial logit model was used to evaluate preferences and derive priority weights (primary analysis), with a latent class model used to explore respondent characteristics that were associated with variation in preference across the sample (see online supplementary analysis). Results A preference was observed to prioritise individuals who demonstrated a strong commitment to maintaining a healthy lifestyle as well as individuals categorised with very severe (BMI≥50 kg/m2) or (to a lesser extent) severe (BMI≥40 kg/m2) obesity, those who already have obesity-related comorbidity, with a family history of obesity, with a greater chance of maintaining weight loss or who had spent a longer time on the wait list. Lifestyle commitment was considered to be more than twice as important as any other criterion. There was little tendency to prioritise according to the age of the recipient. Respondent preferences were dependent on their BMI, previous experience with weight management surgery, current health state and education level. Conclusions This study extends our understanding of the publics’ preferences for priority setting to the context of bariatric surgery, and derives priority weights

  1. Preferences for working in rural clinics among trainee health professionals in Uganda: a discrete choice experiment.

    PubMed

    Rockers, Peter C; Jaskiewicz, Wanda; Wurts, Laura; Kruk, Margaret E; Mgomella, George S; Ntalazi, Francis; Tulenko, Kate

    2012-07-23

    Health facilities require teams of health workers with complementary skills and responsibilities to efficiently provide quality care. In low-income countries, failure to attract and retain health workers in rural areas reduces population access to health services and undermines facility performance, resulting in poor health outcomes. It is important that governments consider health worker preferences in crafting policies to address attraction and retention in underserved areas. We investigated preferences for job characteristics among final year medical, nursing, pharmacy, and laboratory students at select universities in Uganda. Participants were administered a cadre-specific discrete choice experiment that elicited preferences for attributes of potential job postings they were likely to pursue after graduation. Job attributes included salary, facility quality, housing, length of commitment, manager support, training tuition, and dual practice opportunities. Mixed logit models were used to estimate stated preferences for these attributes. Data were collected from 246 medical students, 132 nursing students, 50 pharmacy students and 57 laboratory students. For all student-groups, choice of job posting was strongly influenced by salary, facility quality and manager support, relative to other attributes. For medical and laboratory students, tuition support for future training was also important, while pharmacy students valued opportunities for dual practice. In Uganda, financial and non-financial incentives may be effective in attracting health workers to underserved areas. Our findings contribute to mounting evidence that salary is not the only important factor health workers consider when deciding where to work. Better quality facilities and supportive managers were important to all students. Similarities in preferences for these factors suggest that team-based, facility-level strategies for attracting health workers may be appropriate. Improving facility quality

  2. Decision-makers' preferences for approving new medicines in Wales: a discrete-choice experiment with assessment of external validity.

    PubMed

    Linley, Warren G; Hughes, Dyfrig A

    2013-04-01

    Few studies to date have explored the stated preferences of national decision makers for health technology adoption criteria, and none of these have compared stated decision-making behaviours against actual behaviours. Assessment of the external validity of stated preference studies, such as discrete-choice experiments (DCEs), remains an under-researched area. The primary aim was to explore the preferences of All Wales Medicines Strategy Group (AWMSG) appraisal committee and appraisal sub-committee (the New Medicines Group) members ('appraisal committees') for specific new medicines adoption criteria. Secondary aims were to explore the external validity of respondents' stated preferences and the impact of question choice options upon preference structures in DCEs. A DCE was conducted to estimate appraisal committees members' preferences for incremental cost effectiveness, quality-adjusted life-years (QALYs) gained, annual number of patients expected to be treated, the impact of the disease on patients before treatment, and the assessment of uncertainty in the economic evidence submitted for new medicines compared with current UK NHS treatment. Respondents evaluated 28 pairs of hypothetical new medicines, making a primary forced choice between each pair and a more flexible secondary choice, which permitted either, neither or both new medicines to be chosen. The performance of the resultant models was compared against previous AWMSG decisions. Forty-one out of a total of 80 past and present members of AWMSG appraisal committees completed the DCE. The incremental cost effectiveness of new medicines, and the QALY gains they provide, significantly (p < 0.0001) influence recommendations. Committee members were willing to accept higher incremental cost-effectiveness ratios and lower QALY gains for medicines that treat disease impacting primarily upon survival rather than quality of life, and where uncertainty in the cost-effectiveness estimates has been thoroughly

  3. Commuter choice primer : an employer's guide to implementing effective commuter choice programs

    DOT National Transportation Integrated Search

    2003-01-01

    The Commuter Choice Primer is intended to be a concise, user-friendly reference guide for employers and transportation professionals to developing and implementing worksite commuter choice programs. It is available on-line in both HTML and PDF format...

  4. Probabilistic choice models in health-state valuation research: background, theories, assumptions and applications.

    PubMed

    Arons, Alexander M M; Krabbe, Paul F M

    2013-02-01

    Interest is rising in measuring subjective health outcomes, such as treatment outcomes that are not directly quantifiable (functional disability, symptoms, complaints, side effects and health-related quality of life). Health economists in particular have applied probabilistic choice models in the area of health evaluation. They increasingly use discrete choice models based on random utility theory to derive values for healthcare goods or services. Recent attempts have been made to use discrete choice models as an alternative method to derive values for health states. In this article, various probabilistic choice models are described according to their underlying theory. A historical overview traces their development and applications in diverse fields. The discussion highlights some theoretical and technical aspects of the choice models and their similarity and dissimilarity. The objective of the article is to elucidate the position of each model and their applications for health-state valuation.

  5. Transport synthetic acceleration for long-characteristics assembly-level transport problems

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zika, M.R.; Adams, M.L.

    2000-02-01

    The authors apply the transport synthetic acceleration (TSA) scheme to the long-characteristics spatial discretization for the two-dimensional assembly-level transport problem. This synthetic method employs a simplified transport operator as its low-order approximation. Thus, in the acceleration step, the authors take advantage of features of the long-characteristics discretization that make it particularly well suited to assembly-level transport problems. The main contribution is to address difficulties unique to the long-characteristics discretization and produce a computationally efficient acceleration scheme. The combination of the long-characteristics discretization, opposing reflecting boundary conditions (which are present in assembly-level transport problems), and TSA presents several challenges. The authorsmore » devise methods for overcoming each of them in a computationally efficient way. Since the boundary angular data exist on different grids in the high- and low-order problems, they define restriction and prolongation operations specific to the method of long characteristics to map between the two grids. They implement the conjugate gradient (CG) method in the presence of opposing reflection boundary conditions to solve the TSA low-order equations. The CG iteration may be applied only to symmetric positive definite (SPD) matrices; they prove that the long-characteristics discretization yields an SPD matrix. They present results of the acceleration scheme on a simple test problem, a typical pressurized water reactor assembly, and a typical boiling water reactor assembly.« less

  6. Renormalized vibrations and normal energy transport in 1d FPU-like discrete nonlinear Schrödinger equations.

    PubMed

    Li, Simeng; Li, Nianbei

    2018-03-28

    For one-dimensional (1d) nonlinear atomic lattices, the models with on-site nonlinearities such as the Frenkel-Kontorova (FK) and ϕ 4 lattices have normal energy transport while the models with inter-site nonlinearities such as the Fermi-Pasta-Ulam-β (FPU-β) lattice exhibit anomalous energy transport. The 1d Discrete Nonlinear Schrödinger (DNLS) equations with on-site nonlinearities has been previously studied and normal energy transport has also been found. Here, we investigate the energy transport of 1d FPU-like DNLS equations with inter-site nonlinearities. Extended from the FPU-β lattice, the renormalized vibration theory is developed for the FPU-like DNLS models and the predicted renormalized vibrations are verified by direct numerical simulations same as the FPU-β lattice. However, the energy diffusion processes are explored and normal energy transport is observed for the 1d FPU-like DNLS models, which is different from their atomic lattice counterpart of FPU-β lattice. The reason might be that, unlike nonlinear atomic lattices where models with on-site nonlinearities have one less conserved quantities than the models with inter-site nonlinearities, the DNLS models with on-site or inter-site nonlinearities have the same number of conserved quantities as the result of gauge transformation.

  7. Older People's Preferences for Side Effects Associated with Antimuscarinic Treatments of Overactive Bladder: A Discrete-Choice Experiment.

    PubMed

    Decalf, Veerle H; Huion, Anja M J; Benoit, Dries F; Denys, Marie-Astrid; Petrovic, Mirko; Everaert, Karel C M M

    2017-08-01

    Understanding the importance older people attribute to the different side effects associated with oral antimuscarinic treatments for overactive bladder (OAB) could help inform prescribers, healthcare policy makers and the drug industry. Our objective was to quantify the importance of the most prevalent cognitive and side effects of oral antimuscarinic treatments for OAB in older people. We conducted a discrete-choice experiment (DCE) with the assistance of an interviewer with community-dwelling and hospitalized older people aged >65 years. The DCE involved two hypothetical drugs for imaginary OAB, with three levels of four side effects for each drug, and the International Consultation on Incontinence Questionnaire-Overactive Bladder and EuroQol 5-Dimensions (EQ-5D) questionnaire were also administered. Data were analysed using a conditional logit model. In total, 276 older people participated in the study. The median age was 75 years (interquartile range [IQR] 69-80), 63% were women and 21% had OAB syndrome. The most unwanted side effect in the choice of antimuscarinics for OAB was severe cognitive effects, followed by severe constipation, severe blurred vision, severe dry mouth, moderate cognitive effects and moderate constipation. Severe cognitive effects were at least 1.7 times as important as severe constipation. Exploratory subgroup analysis showed that none of the attributes was found to be significant in people who scored as anxious or depressed on the EQ-5D, and preferences about cognitive effects, constipation and blurred vision were equal in people with and without OAB. Older people attribute more importance to loss of cognitive function as a possible side effect of antimuscarinic treatment than to the three most prevalent possible side effects of this treatment.

  8. How to attract health students to remote areas in Indonesia: a discrete choice experiment.

    PubMed

    Efendi, Ferry; Chen, Ching-Min; Nursalam, Nursalam; Andriyani, Nurul Wachyu Fitriyah; Kurniati, Anna; Nancarrow, Susan Alison

    2016-10-01

    Remote areas of Indonesia lack sufficient health workers to meet the health-care needs of the population. There is an urgent need for evidence regarding interventions to attract health workers and specifically health students to serve in remote areas. The aim of this research was to analyze the job preferences of health students to develop effective policies to improve the recruitment and retention of health students in remote areas. A discrete choice experiment was conducted to investigate health students' preferences regarding job characteristics. This study was conducted in three different regions of Indonesia, with a total included 400 health students. Mixed logit models were used to explore the stated preferences for each attribute. Data were collected from 150 medical, 150 nursing and 100 midwifery students. Medical students gave the highest preference for receiving study assistance, while nursing students viewed salary as the most important. Midwifery students valued advanced quality facilities as an important attribute. This study confirmed the importance of combination interventions in attracting and retaining health workers in remote areas of Indonesia. Money is not the only factor affecting student preferences to take up a rural post; good management and better facilities were viewed as important by all health students. Addressing health student preferences, which are the candidate of future health workforce, would help the nation solve the recruitment and retention issues. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  9. Valuing the benefits of weight loss programs: an application of the discrete choice experiment.

    PubMed

    Roux, Larissa; Ubach, Christina; Donaldson, Cam; Ryan, Mandy

    2004-08-01

    Obesity is a leading health threat. Determination of optimal therapies for long-term weight loss remains a challenge. Evidence suggests that successful weight loss depends on the compliance of weight loss program participants with their weight loss efforts. Despite this, little is known regarding the attributes influencing such compliance. The purpose of this study was to assess, using a discrete choice experiment (DCE), the relative importance of weight loss program attributes to its participants and to express these preferences in terms of their willingness to pay for them. A DCE survey explored the following weight loss program attributes in a sample of 165 overweight adults enrolled in community weight loss programs: cost, travel time required to attend, extent of physician involvement (e.g., none, monthly, every 2 weeks), components (e.g., diet, exercise, behavior change) emphasized, and focus (e.g., group, individual). The rate at which participants were willing to trade among attributes and the willingness to pay for different configurations of combined attributes were estimated using regression modeling. All attributes investigated appeared to be statistically significant. The most important unit change was "program components emphasized" (e.g., moving from diet only to diet and exercise). The majority of participants were willing to pay for weight loss programs that reflected their preferences. The DCE tool was useful in quantifying and understanding individual preferences in obesity management and provided information that could help to maximize the efficiency of existing weight loss programs or the design of new programs.

  10. Priority setting in the Austrian healthcare system: results from a discrete choice experiment and implications for mental health.

    PubMed

    Mentzakis, Emmanouil; Paolucci, Francesco; Rubicko, Georg

    2014-06-01

    The impact of mental conditions is expected to be among the highest ranked causes of illness in high income countries by 2020. With changing health needs, policy makers have to make choices in an environment with increasingly constrained resources and competing demands. Discrete choice experiments have been identified as a useful approach to inform and support decision-making in health care systems and, in particular, its rationing. Policymakers, researchers and health practitioners from Austria participated in an experiment designed to elicit preferences for efficiency and equity in a generic priority setting framework. Using aggregate criteria an empirical measure of the efficiency/equity trade-off is calculated and a selection of health care interventions, including mental health, are ranked in composite league tables (CLTs). With the exception of severity of the condition, all equity parameters decrease attractiveness of an intervention, whereas the opposite holds for all three efficiency criteria. The efficiency/equity ratio (i.e. decision-makers' preference for efficiency over equity) is 3.5 and 5 for interventions targeted at younger and middle age populations, respectively, while for older populations this ratio is negative implying a rejection of all equity criteria. Irrespective of such differences interventions targeting mental health rank highly on all CLTs. Based on system-wide generic decision making criteria, mental health is shown to be a top priority for Austria. Preference-based approaches might offer complementary information to policymakers in priority setting decisions and a useful tool to support rationale rather than ad hoc decision-making.

  11. A discrete choice experiment to explore patients' willingness to risk disease relapse from treatment withdrawal in psoriatic arthritis.

    PubMed

    Rothery, Claire; Bojke, Laura; Richardson, Gerry; Bojke, Chris; Moverley, Anna; Coates, Laura; Thorp, Liz; Waxman, Robin; Helliwell, Philip

    2016-12-01

    The objective of this study is to assess patient preferences for treatment-related benefits and risk of disease relapse in the management of low disease states of psoriatic arthritis (PsA). Focus groups with patients and a literature review were undertaken to determine the characteristics of treatment and symptoms of PsA important to patients. Patient preferences were assessed using a discrete choice experiment which compared hypothetical treatment profiles of the risk and benefits of treatment withdrawal. The risk outcome included increased risk of disease relapse, while benefit outcomes included reduced sickness/nausea from medication and changes in health-related quality of life. Each patient completed 12 choice sets comparing treatment profiles. Preference weights were estimated using a logic regression model, and the maximum acceptable risk in disease relapse for a given improvement in benefit outcomes was elicited. Final sample included 136 patients. Respondents attached the greatest importance to eliminating severe side effects of sickness/nausea and the least importance to a change in risk of relapse. Respondents were willing to accept an increase in the risk of relapse of 32.6 % in order to eliminate the side effects of sickness/nausea. For improvements in health status, the maximum acceptable risk in relapse was comparable to a movement from some to no sickness/nausea. The study suggests that patients in low disease states of PsA are willing to accept greater risks of relapse for improvements in side effects of sickness/nausea and overall health status, with the most important benefit attribute being the elimination of severe sickness or nausea.

  12. Ordinal preference elicitation methods in health economics and health services research: using discrete choice experiments and ranking methods.

    PubMed

    Ali, Shehzad; Ronaldson, Sarah

    2012-09-01

    The predominant method of economic evaluation is cost-utility analysis, which uses cardinal preference elicitation methods, including the standard gamble and time trade-off. However, such approach is not suitable for understanding trade-offs between process attributes, non-health outcomes and health outcomes to evaluate current practices, develop new programmes and predict demand for services and products. Ordinal preference elicitation methods including discrete choice experiments and ranking methods are therefore commonly used in health economics and health service research. Cardinal methods have been criticized on the grounds of cognitive complexity, difficulty of administration, contamination by risk and preference attitudes, and potential violation of underlying assumptions. Ordinal methods have gained popularity because of reduced cognitive burden, lower degree of abstract reasoning, reduced measurement error, ease of administration and ability to use both health and non-health outcomes. The underlying assumptions of ordinal methods may be violated when respondents use cognitive shortcuts, or cannot comprehend the ordinal task or interpret attributes and levels, or use 'irrational' choice behaviour or refuse to trade-off certain attributes. CURRENT USE AND GROWING AREAS: Ordinal methods are commonly used to evaluate preference for attributes of health services, products, practices, interventions, policies and, more recently, to estimate utility weights. AREAS FOR ON-GOING RESEARCH: There is growing research on developing optimal designs, evaluating the rationalization process, using qualitative tools for developing ordinal methods, evaluating consistency with utility theory, appropriate statistical methods for analysis, generalizability of results and comparing ordinal methods against each other and with cardinal measures.

  13. A discrete choice experiment studying students' preferences for scholarships to private medical schools in Japan.

    PubMed

    Goto, Rei; Kakihara, Hiroaki

    2016-02-09

    The shortage of physicians in rural areas and in some specialties is a societal problem in Japan. Expensive tuition in private medical schools limits access to them particularly for students from middle- and low-income families. One way to reduce this barrier and lessen maldistribution is to offer conditional scholarships to private medical schools. A discrete choice experiment is carried out on a total of 374 students considering application to medical schools. The willingness to receive a conditional scholarship program to private medical schools is analyzed. The probability of attending private medical schools significantly decreased because of high tuition, a postgraduate obligation to provide a service in specific specialty areas, and the length of time of this obligation. An obligation to provide a service in rural regions had no significant effect on this probability. To motivate non-applicants to private medical schools to enroll in such schools, a decrease in tuition to around 1.2 million yen (US$ 12,000) or less, which is twice that of public schools, was found to be necessary. Further, it was found that non-applicants to private medical schools choose to apply to such schools even with restrictions if they have tuition support at the public school level. Conditional scholarships for private medical schools may widen access to medical education and simultaneously provide incentives to work in insufficiently served areas.

  14. Parents' preferences for vaccinating daughters against human papillomavirus in the Netherlands: a discrete choice experiment.

    PubMed

    Hofman, Robine; de Bekker-Grob, Esther W; Raat, Hein; Helmerhorst, Theo J M; van Ballegooijen, Marjolein; Korfage, Ida J

    2014-05-15

    To generate knowledge about potential improvements to human papillomavirus (HPV) vaccination information and organization strategies, we assessed how aspects of HPV vaccination are associated with parents' preferences for their daughters' uptake, and which trade-offs parents are willing to make between these aspects. A discrete choice experiment (DCE) was conducted among parents with a daughter aged 10-12 years. Panel mixed logit regression models were used to determine parents' preferences for vaccination. Trade-offs were quantified between four vaccination programme aspects: degree of protection against cervical cancer, duration of protection, risk of serious side-effects, and age of vaccination. Total response rate was 302/983 (31%). All aspects influenced respondents' preferences for HPV vaccination (p < 0.05). Respondents preferred vaccination at age 14 years instead of at a younger age. Respondents were willing to trade-off 11% of the degree of protection to obtain life-time protection instead of 25 years. To obtain a vaccination with a risk of serious side-effects of 1/750,000 instead of 1/150,000, respondents were willing to trade-off 21%. Uptake may rise if the age ranges for free HPV vaccinations are broadened. Based on the trade-offs parents were willing to make, we conclude that uptake would increase if new evidence indicated outcomes are better than are currently understood, particularly for degree and duration of protection.

  15. An empirical comparison of methods for analyzing correlated data from a discrete choice survey to elicit patient preference for colorectal cancer screening

    PubMed Central

    2012-01-01

    Background A discrete choice experiment (DCE) is a preference survey which asks participants to make a choice among product portfolios comparing the key product characteristics by performing several choice tasks. Analyzing DCE data needs to account for within-participant correlation because choices from the same participant are likely to be similar. In this study, we empirically compared some commonly-used statistical methods for analyzing DCE data while accounting for within-participant correlation based on a survey of patient preference for colorectal cancer (CRC) screening tests conducted in Hamilton, Ontario, Canada in 2002. Methods A two-stage DCE design was used to investigate the impact of six attributes on participants' preferences for CRC screening test and willingness to undertake the test. We compared six models for clustered binary outcomes (logistic and probit regressions using cluster-robust standard error (SE), random-effects and generalized estimating equation approaches) and three models for clustered nominal outcomes (multinomial logistic and probit regressions with cluster-robust SE and random-effects multinomial logistic model). We also fitted a bivariate probit model with cluster-robust SE treating the choices from two stages as two correlated binary outcomes. The rank of relative importance between attributes and the estimates of β coefficient within attributes were used to assess the model robustness. Results In total 468 participants with each completing 10 choices were analyzed. Similar results were reported for the rank of relative importance and β coefficients across models for stage-one data on evaluating participants' preferences for the test. The six attributes ranked from high to low as follows: cost, specificity, process, sensitivity, preparation and pain. However, the results differed across models for stage-two data on evaluating participants' willingness to undertake the tests. Little within-patient correlation (ICC ≈ 0) was

  16. Segmenting patients and physicians using preferences from discrete choice experiments.

    PubMed

    Deal, Ken

    2014-01-01

    People often form groups or segments that have similar interests and needs and seek similar benefits from health providers. Health organizations need to understand whether the same health treatments, prevention programs, services, and products should be applied to everyone in the relevant population or whether different treatments need to be provided to each of several segments that are relatively homogeneous internally but heterogeneous among segments. Our objective was to explain the purposes, benefits, and methods of segmentation for health organizations, and to illustrate the process of segmenting health populations based on preference coefficients from a discrete choice conjoint experiment (DCE) using an example study of prevention of cyberbullying among university students. We followed a two-level procedure for investigating segmentation incorporating several methods for forming segments in Level 1 using DCE preference coefficients and testing their quality, reproducibility, and usability by health decision makers. Covariates (demographic, behavioral, lifestyle, and health state variables) were included in Level 2 to further evaluate quality and to support the scoring of large databases and developing typing tools for assigning those in the relevant population, but not in the sample, to the segments. Several segmentation solution candidates were found during the Level 1 analysis, and the relationship of the preference coefficients to the segments was investigated using predictive methods. Those segmentations were tested for their quality and reproducibility and three were found to be very close in quality. While one seemed better than others in the Level 1 analysis, another was very similar in quality and proved ultimately better in predicting segment membership using covariates in Level 2. The two segments in the final solution were profiled for attributes that would support the development and acceptance of cyberbullying prevention programs among university

  17. Household Size and the Decision to Purchase Health Insurance in Cambodia: Results of a Discrete-Choice Experiment with Scale Adjustment.

    PubMed

    Ozawa, Sachiko; Grewal, Simrun; Bridges, John F P

    2016-04-01

    Community-based health insurance (CBHI) schemes have been introduced in low- and middle-income countries to increase health service utilization and provide financial protection from high healthcare expenditures. We assess the impact of household size on decisions to enroll in CBHI and demonstrate how to correct for group disparity in scale (i.e. variance differences). A discrete choice experiment was conducted across five CBHI attributes. Preferences were elicited through forced-choice paired comparison choice tasks designed based on D-efficiency. Differences in preferences were examined between small (1-4 family members) and large (5-12 members) households using conditional logistic regression. Swait and Louviere test was used to identify and correct for differences in scale. One-hundred and sixty households were surveyed in Northwest Cambodia. Increased insurance premium was associated with disutility [odds ratio (OR) 0.61, p < 0.01], while significant increase in utility was noted for higher hospital fee coverage (OR 10.58, p < 0.01), greater coverage of travel and meal costs (OR 4.08, p < 0.01), and more frequent communication with the insurer (OR 1.33, p < 0.01). While the magnitude of preference for hospital fee coverage appeared larger for the large household group (OR 14.15) compared to the small household group (OR 8.58), differences in scale were observed (p < 0.05). After adjusting for scale (k, ratio of scale between large to small household groups = 1.227, 95 % confidence interval 1.002-1.515), preference differences by household size became negligible. Differences in stated preferences may be due to scale, or variance differences between groups, rather than true variations in preference. Coverage of hospital fees, travel and meal costs are given significant weight in CBHI enrollment decisions regardless of household size. Understanding how community members make decisions about health insurance can inform low- and middle-income countries' paths

  18. Renal transplant patients' preference for the supply and delivery of immunosuppressants in Wales: a discrete choice experiment.

    PubMed

    Hagemi, Anke; Plumpton, Catrin; Hughes, Dyfrig A

    2017-10-02

    Prescribing policy recommendations aimed at moving immunosuppressant prescribing for renal transplant patients from primary to secondary care may result in benefits of increased safety and reduced cost. However, there is little evidence of patients' preferences for receiving their immunosuppressant therapy from hospitals compared to community dispensing. The aim of this study was to elicit patient preferences for different service configurations focusing in particular on home delivery versus collection of medication from hospital. A discrete choice experiment was administered to 265 renal transplant patients in North Wales. Respondents were presented 18 pairwise choices, labelled as either home delivery or hospital collection, and described by the attributes: frequency of supply, waiting time (for delivery or collection) and method of ordering (provider contact, patient contact via phone, patient contact electronically). Data were analysed using a random-effects logit model and marginal rates of substitution calculated based on the waiting time attribute. A response rate of 63% was achieved, with 5332 usable observations from 150 respondents. Method of delivery (β coefficient 1.21; 95% confidence interval 1.05 to 1.38), frequency of supply (0.05; 0.03 to 0.08) waiting time (-0.00, -0.00 to -0.00), provider contact (desirable) (0.20; 0.12 to 0.27), patient contact by telephone (desirable) (0.09; 0.01 to 0.17) and patient contact electronically (undesirable) (-0.292; -0.37 to -0.21) were statistically significant (p < 0.05). Results indicate that patients are willing to increase waiting time by nearly 10 h to have a home delivery service. Patients indicate a clear preference for a home delivery service. They prefer providers to make contact when new immunosuppressant supplies are required and show preference against ordering medication electronically. A policy for secondary care prescribing and hospital collection of medicines does not align with this preference.

  19. Numerical stability analysis of two-dimensional solute transport along a discrete fracture in a porous rock matrix

    NASA Astrophysics Data System (ADS)

    Watanabe, Norihiro; Kolditz, Olaf

    2015-07-01

    This work reports numerical stability conditions in two-dimensional solute transport simulations including discrete fractures surrounded by an impermeable rock matrix. We use an advective-dispersive problem described in Tang et al. (1981) and examine the stability of the Crank-Nicolson Galerkin finite element method (CN-GFEM). The stability conditions are analyzed in terms of the spatial discretization length perpendicular to the fracture, the flow velocity, the diffusion coefficient, the matrix porosity, the fracture aperture, and the fracture longitudinal dispersivity. In addition, we verify applicability of the recently developed finite element method-flux corrected transport (FEM-FCT) method by Kuzmin () to suppress oscillations in the hybrid system, with a comparison to the commonly utilized Streamline Upwinding/Petrov-Galerkin (SUPG) method. Major findings of this study are (1) the mesh von Neumann number (Fo) ≥ 0.373 must be satisfied to avoid undershooting in the matrix, (2) in addition to an upper bound, the Courant number also has a lower bound in the fracture in cases of low dispersivity, and (3) the FEM-FCT method can effectively suppress the oscillations in both the fracture and the matrix. The results imply that, in cases of low dispersivity, prerefinement of a numerical mesh is not sufficient to avoid the instability in the hybrid system if a problem involves evolutionary flow fields and dynamic material parameters. Applying the FEM-FCT method to such problems is recommended if negative concentrations cannot be tolerated and computing time is not a strong issue.

  20. Dealing with the health state 'dead' when using discrete choice experiments to obtain values for EQ-5D-5L heath states.

    PubMed

    Ramos-Goñi, Juan Manuel; Rivero-Arias, Oliver; Errea, María; Stolk, Elly A; Herdman, Michael; Cabasés, Juan Manuel

    2013-07-01

    To evaluate two different methods to obtain a dead (0)--full health (1) scale for EQ-5D-5L valuation studies when using discrete choice (DC) modeling. The study was carried out among 400 respondents from Barcelona who were representative of the Spanish population in terms of age, sex, and level of education. The DC design included 50 pairs of health states in five blocks. Participants were forced to choose between two EQ-5D-5L states (A and B). Two extra questions concerned whether A and B were considered worse than dead. Each participant performed ten choice exercises. In addition, values were collected using lead-time trade-off (lead-time TTO), for which 100 states in ten blocks were selected. Each participant performed five lead-time TTO exercises. These consisted of DC models offering the health state 'dead' as one of the choices--for which all participants' responses were used (DCdead)--and a model that included only the responses of participants who chose at least one state as worse than dead (WTD) (DCWTD). The study also estimated DC models rescaled with lead-time TTO data and a lead-time TTO linear model. The DC(dead) and DCWTD models produced relatively similar results, although the coefficients in the DCdead model were slightly lower. The DC model rescaled with lead-time TTO data produced higher utility decrements. Lead-time TTO produced the highest utility decrements. The incorporation of the state 'dead' in the DC models produces results in concordance with DC models that do not include 'dead'.

  1. Public preferences for prioritizing preventive and curative health care interventions: a discrete choice experiment.

    PubMed

    Luyten, Jeroen; Kessels, Roselinde; Goos, Peter; Beutels, Philippe

    2015-03-01

    Setting fair health care priorities counts among the most difficult ethical challenges our societies are facing. To elicit through a discrete choice experiment the Belgian adult population's (18-75 years; N = 750) preferences for prioritizing health care and investigate whether these preferences are different for prevention versus cure. We used a Bayesian D-efficient design with partial profiles, which enables considering a large number of attributes and interaction effects. We included the following attributes: 1) type of intervention (cure vs. prevention), 2) effectiveness, 3) risk of adverse effects, 4) severity of illness, 5) link between the illness and patient's health-related lifestyle, 6) time span between intervention and effect, and 7) patient's age group. All attributes were statistically significant contributors to the social value of a health care program, with patient's lifestyle and age being the most influential ones. Interaction effects were found, showing that prevention was preferred to cure for disease in young adults, as well as for severe and lethal disease in people of any age. However, substantial differences were found in the preferences of respondents from different age groups, with different lifestyles and different health states. Our study suggests that according to the Belgian public, contextual factors of health gains such as patient's age and health-related lifestyle should be considered in priority setting decisions. The studies, however, revealed substantial disagreement in opinion between different population subgroups. Copyright © 2015 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  2. Discrete Element Method Modeling of Bedload Transport: Towards a physics-based link between bed surface variability and particle entrainment statistics

    NASA Astrophysics Data System (ADS)

    Ghasemi, A.; Borhani, S.; Viparelli, E.; Hill, K. M.

    2017-12-01

    The Exner equation provides a formal mathematical link between sediment transport and bed morphology. It is typically represented in a discrete formulation where there is a sharp geometric interface between the bedload layer and the bed, below which no particles are entrained. For high temporally and spatially resolved models, this is strictly correct, but typically this is applied in such a way that spatial and temporal fluctuations in the bed surface (bedforms and otherwise) are not captured. This limits the extent to which the exchange between particles in transport and the sediment bed are properly represented, particularly problematic for mixed grain size distributions that exhibit segregation. Nearly two decades ago, Parker (2000) provided a framework for a solution to this dilemma in the form of a probabilistic Exner equation, partially experimentally validated by Wong et al. (2007). We present a computational study designed to develop a physics-based framework for understanding the interplay between physical parameters of the bed and flow and parameters in the Parker (2000) probabilistic formulation. To do so we use Discrete Element Method simulations to relate local time-varying parameters to long-term macroscopic parameters. These include relating local grain size distribution and particle entrainment and deposition rates to long- average bed shear stress and the standard deviation of bed height variations. While relatively simple, these simulations reproduce long-accepted empirically determined transport behaviors such as the Meyer-Peter and Muller (1948) relationship. We also find that these simulations reproduce statistical relationships proposed by Wong et al. (2007) such as a Gaussian distribution of bed heights whose standard deviation increases with increasing bed shear stress. We demonstrate how the ensuing probabilistic formulations provide insight into the transport and deposition of both narrow and wide grain size distribution.

  3. Investigating the impact of design characteristics on statistical efficiency within discrete choice experiments: A systematic survey.

    PubMed

    Vanniyasingam, Thuva; Daly, Caitlin; Jin, Xuejing; Zhang, Yuan; Foster, Gary; Cunningham, Charles; Thabane, Lehana

    2018-06-01

    This study reviews simulation studies of discrete choice experiments to determine (i) how survey design features affect statistical efficiency, (ii) and to appraise their reporting quality. Statistical efficiency was measured using relative design (D-) efficiency, D-optimality, or D-error. For this systematic survey, we searched Journal Storage (JSTOR), Since Direct, PubMed, and OVID which included a search within EMBASE. Searches were conducted up to year 2016 for simulation studies investigating the impact of DCE design features on statistical efficiency. Studies were screened and data were extracted independently and in duplicate. Results for each included study were summarized by design characteristic. Previously developed criteria for reporting quality of simulation studies were also adapted and applied to each included study. Of 371 potentially relevant studies, 9 were found to be eligible, with several varying in study objectives. Statistical efficiency improved when increasing the number of choice tasks or alternatives; decreasing the number of attributes, attribute levels; using an unrestricted continuous "manipulator" attribute; using model-based approaches with covariates incorporating response behaviour; using sampling approaches that incorporate previous knowledge of response behaviour; incorporating heterogeneity in a model-based design; correctly specifying Bayesian priors; minimizing parameter prior variances; and using an appropriate method to create the DCE design for the research question. The simulation studies performed well in terms of reporting quality. Improvement is needed in regards to clearly specifying study objectives, number of failures, random number generators, starting seeds, and the software used. These results identify the best approaches to structure a DCE. An investigator can manipulate design characteristics to help reduce response burden and increase statistical efficiency. Since studies varied in their objectives, conclusions

  4. Evaluating the effect of internal aperture variability on transport in kilometer scale discrete fracture networks

    DOE PAGES

    Makedonska, Nataliia; Hyman, Jeffrey D.; Karra, Satish; ...

    2016-08-01

    The apertures of natural fractures in fractured rock are highly heterogeneous. However, in-fracture aperture variability is often neglected in flow and transport modeling and individual fractures are assumed to have uniform aperture distribution. The relative importance of in-fracture variability in flow and transport modeling within kilometer-scale fracture networks has been under debate for a long time, since the flow in each single fracture is controlled not only by in-fracture variability but also by boundary conditions. Computational limitations have previously prohibited researchers from investigating the relative importance of in-fracture variability in flow and transport modeling within large-scale fracture networks. We addressmore » this question by incorporating internal heterogeneity of individual fractures into flow simulations within kilometer scale three-dimensional fracture networks, where fracture intensity, P 32 (ratio between total fracture area and domain volume) is between 0.027 and 0.031 [1/m]. The recently developed discrete fracture network (DFN) simulation capability, dfnWorks, is used to generate kilometer scale DFNs that include in-fracture aperture variability represented by a stationary log-normal stochastic field with various correlation lengths and variances. The Lagrangian transport parameters, non-reacting travel time, , and cumulative retention, , are calculated along particles streamlines. As a result, it is observed that due to local flow channeling early particle travel times are more sensitive to in-fracture aperture variability than the tails of travel time distributions, where no significant effect of the in-fracture aperture variations and spatial correlation length is observed.« less

  5. Evaluating the effect of internal aperture variability on transport in kilometer scale discrete fracture networks

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Makedonska, Nataliia; Hyman, Jeffrey D.; Karra, Satish

    The apertures of natural fractures in fractured rock are highly heterogeneous. However, in-fracture aperture variability is often neglected in flow and transport modeling and individual fractures are assumed to have uniform aperture distribution. The relative importance of in-fracture variability in flow and transport modeling within kilometer-scale fracture networks has been under debate for a long time, since the flow in each single fracture is controlled not only by in-fracture variability but also by boundary conditions. Computational limitations have previously prohibited researchers from investigating the relative importance of in-fracture variability in flow and transport modeling within large-scale fracture networks. We addressmore » this question by incorporating internal heterogeneity of individual fractures into flow simulations within kilometer scale three-dimensional fracture networks, where fracture intensity, P 32 (ratio between total fracture area and domain volume) is between 0.027 and 0.031 [1/m]. The recently developed discrete fracture network (DFN) simulation capability, dfnWorks, is used to generate kilometer scale DFNs that include in-fracture aperture variability represented by a stationary log-normal stochastic field with various correlation lengths and variances. The Lagrangian transport parameters, non-reacting travel time, , and cumulative retention, , are calculated along particles streamlines. As a result, it is observed that due to local flow channeling early particle travel times are more sensitive to in-fracture aperture variability than the tails of travel time distributions, where no significant effect of the in-fracture aperture variations and spatial correlation length is observed.« less

  6. Financial incentives to discontinue long-term benzodiazepine use: a discrete choice experiment investigating patient preferences and willingness to participate

    PubMed Central

    Marti, Joachim; Bachhuber, Marcus; Feingold, Jordyn; Meads, David; Richards, Michael; Hennessy, Sean

    2017-01-01

    Objectives Investigate the acceptability of financial incentives for initiating a medically supervised benzodiazepine discontinuation programme among people with long-term benzodiazepine use and to identify programme features that influence willingness to participate. Methods We conducted a discrete choice experiment in which we presented a variety of incentive-based programs to a sample of older adults with long-term benzodiazepine use identified using the outpatient electronic health record of a university-owned health system. We studied four programme variables: incentive amount for initiating the programme, incentive amount for successful benzodiazepine discontinuation, lottery versus certain payment and whether partial payment was given for dose reduction. Respondents reported their willingness to participate in the programmes and additional information was collected on demographics, history of use and anxiety symptoms. Results The overall response rate was 28.4%. Among the 126 respondents, all four programme variables influenced stated preferences. Respondents strongly preferred guaranteed cash-based incentives as opposed to a lottery, and the dollar amount of both the starting and conditional incentives had a substantial impact on choice. Willingness to participate increased with the amount of conditional incentive. Programme participation also varied by gender, duration of use and income. Conclusions Participation in an incentive-based benzodiazepine discontinuation programme might be relatively low, but is modifiable by programme variables including incentive amounts. These results will be helpful to inform the design of future trials of benzodiazepine discontinuation programmes. Further research is needed to assess the financial viability and potential cost-effectiveness of such economic incentives. PMID:28988167

  7. Therapy preferences of patients with lung and colon cancer: a discrete choice experiment.

    PubMed

    Schmidt, Katharina; Damm, Kathrin; Vogel, Arndt; Golpon, Heiko; Manns, Michael P; Welte, Tobias; Graf von der Schulenburg, J-Matthias

    2017-01-01

    There is increasing interest in studies that examine patient preferences to measure health-related outcomes. Understanding patients' preferences can improve the treatment process and is particularly relevant for oncology. In this study, we aimed to identify the subgroup-specific treatment preferences of German patients with lung cancer (LC) or colorectal cancer (CRC). Six discrete choice experiment (DCE) attributes were established on the basis of a systematic literature review and qualitative interviews. The DCE analyses comprised generalized linear mixed-effects model and latent class mixed logit model. The study cohort comprised 310 patients (194 with LC, 108 with CRC, 8 with both types of cancer) with a median age of 63 (SD =10.66) years. The generalized linear mixed-effects model showed a significant ( P <0.05) degree of association for all of the tested attributes. "Strongly increased life expectancy" was the attribute given the greatest weight by all patient groups. Using latent class mixed logit model analysis, we identified three classes of patients. Patients who were better informed tended to prefer a more balanced relationship between length and health-related quality of life (HRQoL) than those who were less informed. Class 2 (LC patients with low HRQoL who had undergone surgery) gave a very strong weighting to increased length of life. We deduced from Class 3 patients that those with a relatively good life expectancy (CRC compared with LC) gave a greater weight to moderate effects on HRQoL than to a longer life. Overall survival was the most important attribute of therapy for patients with LC or CRC. Differences in treatment preferences between subgroups should be considered in regard to treatment and development of guidelines. Patients' preferences were not affected by sex or age, but were affected by the cancer type, HRQoL, surgery status, and the main source of information on the disease.

  8. Women's preferences for aspects of labor management: results from a discrete choice experiment.

    PubMed

    Scotland, Graham S; McNamee, Paul; Cheyne, Helen; Hundley, Vanora; Barnett, Carol

    2011-03-01

    The latent phase of labor can vary greatly in duration, and many women are uncertain about when to contact the maternity unit. The aim of this study was to elicit and value women's preferences for some aspects of labor management. A questionnaire was sent to 1,251 women who had recently given birth to their first child at one of 14 maternity units in Scotland. Discrete choice questions were used to measure women's preferences for five attributes of care: number of visits (assessments) before admission to the labor ward, time spent on the labor ward before delivery, mobility during labor, pain relief required, and mode of delivery. Responses were analyzed for the sample as a whole and for subgroups defined by recent experiences of labor. A total of 730 (58.4%) questionnaires were returned and analyzed. Women expressed a preference for fewer visits before admission, shorter times on the labor ward before delivery, mobility during labor, normal vaginal deliveries, and moderate forms of pain relief (Entonox and opiates). Subgroup analysis suggests that women's preferences for pain relief are influenced by their recent labor experience. The elicited preference values provide a means for estimating the tradeoffs women are willing to make between attributes of labor management. Women appear to dislike being turned away from the labor ward before admission for delivery. Extra visits before admission only appear to be a price worth paying if they result in reductions in the duration of time spent on the labor ward, reductions in the chance of being immobilized in hospital during labor, or a lower chance of requiring an instrumental or operative delivery. © 2010, Copyright the Authors. Journal compilation © 2010, Wiley Periodicals, Inc.

  9. Patients' preferences for anti-osteoporosis drug treatment: a cross-European discrete choice experiment.

    PubMed

    Hiligsmann, Mickaël; Dellaert, Benedict G; Dirksen, Carmen D; Watson, Verity; Bours, Sandrine; Goemaere, Stefan; Reginster, Jean-Yves; Roux, Christian; McGowan, Bernie; Silke, Carmel; Whelan, Bryan; Diez-Perez, Adolfo; Torres, Elisa; Papadakis, Georgios; Rizzoli, Rene; Cooper, Cyrus; Pearson, Gill; Boonen, Annelies

    2017-07-01

    To estimate the preferences of osteoporotic patients for medication attributes, and analyse data from seven European countries. A discrete choice experiment was conducted in Belgium, France, Ireland, the Netherlands, Spain, Switzerland and the UK. Patients were asked to choose repeatedly between two hypothetical unlabelled drug treatments (and an opt-out option) that varied with respect to four attributes: efficacy in reducing the risk of fracture, type of potential common side effects, and mode and frequency of administration. In those countries in which patients contribute to the cost of their treatment directly, a fifth attribute was added: out-of-pocket cost. A mixed logit panel model was used to estimate patients' preferences. In total, 1124 patients completed the experiment, with a sample of between 98 and 257 patients per country. In all countries, patients preferred treatment with higher effectiveness, and 6-monthly subcutaneous injection was always preferred over weekly oral tablets. In five countries, patients also preferred a monthly oral tablet and yearly i.v. injections over weekly oral tablets. In the three countries where the out-of-pocket cost was included as an attribute, lower costs significantly contributed to the treatment preference. Between countries, there were statistically significant differences for 13 out of 42 attribute/level interactions. We found statistically significant differences in patients' preferences for anti-osteoporosis medications between countries, especially for the mode of administration. Our findings emphasized that international treatment recommendations should allow for local adaptation, and that understanding individual preferences is important if we want to improve the quality of clinical care for patients with osteoporosis. © The Author 2017. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  10. Men's preferences and trade-offs for prostate cancer screening: a discrete choice experiment.

    PubMed

    Howard, Kirsten; Salkeld, Glenn P; Patel, Manish I; Mann, Graham J; Pignone, Michael P

    2015-12-01

    Prostate cancer screening using prostate-specific antigen (PSA) remains controversial. In deciding about screening, men must weigh the benefits and harms: little is known about benefit: harm trade-offs men are willing to accept. The objective of this study was to assess men's preferences for PSA screening, and the trade-offs between benefits and harms men are willing to accept when deciding about screening. Preferences of 662 men aged 40-69 were assessed using a discrete choice experiment. PSA screening was described by six attributes: prostate cancer deaths, prostate cancer diagnoses, unnecessary biopsies from false-positive PSA tests, impotence, urinary incontinence/bowel problems and cost. A mixed logit model was used to examine the influence of attributes on men's preferences for PSA testing; benefit: harm trade-offs were also calculated. Men's preferences were significantly influenced by test characteristics, particularly potential mortality benefit, unnecessary biopsies and likelihood of urinary incontinence or bowel problems; preferences were also influenced by age, prior PSA testing experience and perceived risk of prostate cancer. Men were willing to accept between 65 and 233 of 10 000 extra men with unnecessary biopsies, and between 31 and 72 of 10 000 extra men with incontinence/bowel problems to avoid one prostate cancer death. Differences in valuations of attributes and trade-offs acceptable to men of different ages suggest a one size fits all approach to PSA testing, regardless of age, may not reflect men's preferences. Our results can be used by policymakers to ensure screening programmes are in line with men's preferences and by clinicians and patients to facilitate informed discussions of the most relevant benefits and downsides of PSA screening for an individual man. © 2014 John Wiley & Sons Ltd.

  11. Reimagining cost recovery in Pakistan's irrigation system through willingness-to-pay estimates for irrigation water from a discrete choice experiment

    NASA Astrophysics Data System (ADS)

    Bell, Andrew Reid; Shah, M. Azeem Ali; Ward, Patrick S.

    2014-08-01

    It is widely argued that farmers are unwilling to pay adequate fees for surface water irrigation to recover the costs associated with maintenance and improvement of delivery systems. In this paper, we use a discrete choice experiment to study farmer preferences for irrigation characteristics along two branch canals in Punjab Province in eastern Pakistan. We find that farmers are generally willing to pay well in excess of current surface water irrigation costs for increased surface water reliability and that the amount that farmers are willing to pay is an increasing function of their existing surface water supply as well as location along the main canal branch. This explicit translation of implicit willingness-to-pay (WTP) for water (via expenditure on groundwater pumping) to WTP for reliable surface water demonstrates the potential for greatly enhanced cost recovery in the Indus Basin Irrigation System via appropriate setting of water user fees, driven by the higher WTP of those currently receiving reliable supplies.

  12. Reimagining cost recovery in Pakistan's irrigation system through willingness-to-pay estimates for irrigation water from a discrete choice experiment

    PubMed Central

    Bell, Andrew Reid; Shah, M Azeem Ali; Ward, Patrick S

    2014-01-01

    It is widely argued that farmers are unwilling to pay adequate fees for surface water irrigation to recover the costs associated with maintenance and improvement of delivery systems. In this paper, we use a discrete choice experiment to study farmer preferences for irrigation characteristics along two branch canals in Punjab Province in eastern Pakistan. We find that farmers are generally willing to pay well in excess of current surface water irrigation costs for increased surface water reliability and that the amount that farmers are willing to pay is an increasing function of their existing surface water supply as well as location along the main canal branch. This explicit translation of implicit willingness-to-pay (WTP) for water (via expenditure on groundwater pumping) to WTP for reliable surface water demonstrates the potential for greatly enhanced cost recovery in the Indus Basin Irrigation System via appropriate setting of water user fees, driven by the higher WTP of those currently receiving reliable supplies. PMID:25552779

  13. A protocol for a discrete choice experiment: understanding preferences of patients with cancer towards their cancer care across metropolitan and rural regions in Australia.

    PubMed

    Wong, Shu Fen; Norman, Richard; Dunning, Trisha L; Ashley, David M; Lorgelly, Paula K

    2014-10-24

    Medical decision-making in oncology is a complicated process and to date there are few studies examining how patients with cancer make choices with respect to different features of their care. It is also unknown whether patient choices vary by geographical location and how location could account for observed rural and metropolitan cancer differences. This paper describes an ongoing study that aims to (1) examine patient and healthcare-related factors that influence choices of patients with cancer; (2) measure and quantify preferences of patients with cancer towards cancer care using a discrete choice experiment (DCE) and (3) explore preference heterogeneity between metropolitan and rural locations. A DCE is being conducted to understand how patients with cancer choose between two clinical scenarios accounting for different patient and healthcare-related factors (and levels). Preliminary qualitative research was undertaken to guide the development of an appropriate DCE design including characteristics that are important and relevant to patients with cancer. A fractional factorial design using the D-efficiency criteria was used to estimate interactions among attributes. Multinomial logistic regression will be used for the primary DCE analysis and to control for sociodemographic and clinical characteristics. The Barwon Health Human Research Ethics Committee approved the study. Findings from the study will be presented in national/international conferences and peer-reviewed journals. Our results will form the basis of a feasibility study to inform the development of a larger scale study into preferences of patients with cancer and their association with cancer outcomes. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  14. Flexible Automatic Discretization for Finite Differences: Eliminating the Human Factor

    NASA Astrophysics Data System (ADS)

    Pranger, Casper

    2017-04-01

    In the geophysical numerical modelling community, finite differences are (in part due to their small footprint) a popular spatial discretization method for PDEs in the regular-shaped continuum that is the earth. However, they rapidly become prone to programming mistakes when physics increase in complexity. To eliminate opportunities for human error, we have designed an automatic discretization algorithm using Wolfram Mathematica, in which the user supplies symbolic PDEs, the number of spatial dimensions, and a choice of symbolic boundary conditions, and the script transforms this information into matrix- and right-hand-side rules ready for use in a C++ code that will accept them. The symbolic PDEs are further used to automatically develop and perform manufactured solution benchmarks, ensuring at all stages physical fidelity while providing pragmatic targets for numerical accuracy. We find that this procedure greatly accelerates code development and provides a great deal of flexibility in ones choice of physics.

  15. Facilitating the implementation of pharmacokinetic-guided dosing of prophylaxis in haemophilia care by discrete choice experiment.

    PubMed

    Lock, J; de Bekker-Grob, E W; Urhan, G; Peters, M; Meijer, K; Brons, P; van der Meer, F J M; Driessens, M H E; Collins, P W; Fijnvandraat, K; Leebeek, F W G; Cnossen, M H

    2016-01-01

    Patients', parents' and providers' preferences with regard to medical innovations may have a major impact on their implementation. To evaluate barriers and facilitators for individualized pharmacokinetic (PK)-guided dosing of prophylaxis in haemophilia patients, parents of young patients, and treating professionals by discrete choice experiment (DCE) questionnaire. The study population consisted of patients with haemophilia currently or previously on prophylactic treatment with factor concentrate (n = 114), parents of patients aged 12-18 years (n = 19) and haemophilia professionals (n = 91). DCE data analysis was performed, taking preference heterogeneity into account. Overall, patients and parents, and especially professionals were inclined to opt for PK-guided dosing of prophylaxis. In addition, if bleeding was consequently reduced, more frequent infusions were acceptable. However, daily dosing remained an important barrier for all involved. 'Reduction of costs for society' was a facilitator for implementation in all groups. To achieve implementation of individualized PK-guided dosing of prophylaxis in haemophilia, reduction of bleeding risk and reduction of costs for society should be actively discussed as they are motivating for implementation; daily dosing is still reported to be a barrier for all groups. The knowledge of these preferences will enlarge support for this innovation, and aid in the drafting of implementable guidelines and information brochures for patients, parents and professionals. © 2015 John Wiley & Sons Ltd.

  16. Comparison of approximate solutions to the phonon Boltzmann transport equation with the relaxation time approximation: Spherical harmonics expansions and the discrete ordinates method

    NASA Astrophysics Data System (ADS)

    Christenson, J. G.; Austin, R. A.; Phillips, R. J.

    2018-05-01

    The phonon Boltzmann transport equation is used to analyze model problems in one and two spatial dimensions, under transient and steady-state conditions. New, explicit solutions are obtained by using the P1 and P3 approximations, based on expansions in spherical harmonics, and are compared with solutions from the discrete ordinates method. For steady-state energy transfer, it is shown that analytic expressions derived using the P1 and P3 approximations agree quantitatively with the discrete ordinates method, in some cases for large Knudsen numbers, and always for Knudsen numbers less than unity. However, for time-dependent energy transfer, the PN solutions differ qualitatively from converged solutions obtained by the discrete ordinates method. Although they correctly capture the wave-like behavior of energy transfer at short times, the P1 and P3 approximations rely on one or two wave velocities, respectively, yielding abrupt, step-changes in temperature profiles that are absent when the angular dependence of the phonon velocities is captured more completely. It is shown that, with the gray approximation, the P1 approximation is formally equivalent to the so-called "hyperbolic heat equation." Overall, these results support the use of the PN approximation to find solutions to the phonon Boltzmann transport equation for steady-state conditions. Such solutions can be useful in the design and analysis of devices that involve heat transfer at nanometer length scales, where continuum-scale approaches become inaccurate.

  17. Evaluating consumer preferences for healthy eating from Community Kitchens in low-income urban areas: A discrete choice experiment of Comedores Populares in Peru.

    PubMed

    Buttorff, Christine; Trujillo, Antonio J; Diez-Canseco, Francisco; Bernabe-Ortiz, Antonio; Miranda, J Jaime

    2015-09-01

    Many low-income individuals from around the world rely on local food vendors for daily sustenance. These small vendors quickly provide convenient, low-priced, tasty foods, however, they may be low in nutritional value. These vendors serve as an opportunity to use established delivery channels to explore the introduction of healthier products, e.g. fresh salad and fruits, to low-income populations. We sought to understand preferences for items prepared in Comedores Populares (CP), government-supported food vendors serving low-income Peruvians, to determine whether it would be feasible to introduce healthier items, specifically fruits and vegetables. We used a best-worst discrete choice experiment (DCE) that allowed participants to select their favorite and least favorite option from a series of three hypothetical menus. The characteristics were derived from a series of formative qualitative interviews conducted previously in the CPs. We examined preferences for six characteristics: price, salad, soup, sides, meat and fruit. A total of 432 individuals, from two districts in Lima, Peru responded to a discrete choice experiment and demographic survey in 2012. For the DCE, price contributed the most to individual's utility relative to the other attributes, with salad and soup following closely. Sides (e.g. rice and beans) were the least important. The willingness to pay for a meal with a large main course and salad was 2.6 Nuevos Soles, roughly a 1 Nuevo Sol increase from the average menu price, or USD $0.32 dollars. The willingness to pay for a meal with fruit was 1.6 Nuevo Soles. Overall, the perceived quality of service and food served in the CPs is high. The willingness to pay indicates that healthier additions to meals are feasible. Understanding consumer preferences can help policy makers design healthier meals in an organization with the potential to scale up to reach a considerable number of low-income families. Copyright © 2015 Elsevier Ltd. All rights

  18. How to make rural jobs more attractive to health workers. Findings from a discrete choice experiment in Tanzania.

    PubMed

    Kolstad, Julie Riise

    2011-02-01

    The geographical imbalance of the health workforce in Tanzania represents a serious problem when it comes to delivering crucial health services to a large share of the population. This study provides new quantitative information about how to make jobs in rural areas more attractive to newly educated clinical officers (COs). A unique data set stemming from a discrete choice experiment with CO finalists in Tanzania is applied. The results show that offering continuing education after a certain period of service is one of the most powerful recruitment instruments the authorities have available. Increased salaries and hardship allowances will also substantially increase recruitment in rural areas. Offers of decent housing and good infrastructure, including the provision of equipment, will increase recruitment to rural remote areas but not as much as higher wages and offers of education. Women are less responsive to pecuniary incentives and are more concerned with factors that directly allow them to do a good job, while those with parents living in a remote rural area are generally less responsive to the proposed policies. When the willingness to help other people is a strong motivating force, policies that improve the conditions for helping people appear particularly effective.

  19. Using discrete choice modeling to generate resource selection functions for female polar bears in the Beaufort Sea

    USGS Publications Warehouse

    Durner, George M.; Amstrup, Steven C.; Nielson, Ryan M.; McDonald, Trent; Huzurbazar, Snehalata

    2004-01-01

    Polar bears (Ursus maritimus) depend on ice-covered seas to satisfy life history requirements. Modern threats to polar bears include oil spills in the marine environment and changes in ice composition resulting from climate change. Managers need practical models that explain the distribution of bears in order to assess the impacts of these threats. We explored the use of discrete choice models to describe habitat selection by female polar bears in the Beaufort Sea. Using stepwise procedures we generated resource selection models of habitat use. Sea ice characteristics and ocean depths at known polar bear locations were compared to the same features at randomly selected locations. Models generated for each of four seasons confirmed complexities of habitat use by polar bears and their response to numerous factors. Bears preferred shallow water areas where different ice types intersected. Variation among seasons was reflected mainly in differential selection of total ice concentration, ice stages, floe sizes, and their interactions. Distance to the nearest ice interface was a significant term in models for three seasons. Water depth was selected as a significant term in all seasons, possibly reflecting higher productivity in shallow water areas. Preliminary tests indicate seasonal models can predict polar bear distribution based on prior sea ice data.

  20. Do Financial Incentives Influence GPs' Decisions to Do After-hours Work? A Discrete Choice Labour Supply Model.

    PubMed

    Broadway, Barbara; Kalb, Guyonne; Li, Jinhu; Scott, Anthony

    2017-12-01

    This paper analyses doctors' supply of after-hours care (AHC), and how it is affected by personal and family circumstances as well as the earnings structure. We use detailed survey data from a large sample of Australian General Practitioners (GPs) to estimate a structural, discrete choice model of labour supply and AHC. This allows us to jointly model GPs' decisions on the number of daytime-weekday working hours and the probability of providing AHC. We simulate GPs' labour supply responses to an increase in hourly earnings, both in a daytime-weekday setting and for AHC. GPs increase their daytime-weekday working hours if their hourly earnings in this setting increase, but only to a very small extent. GPs are somewhat more likely to provide AHC if their hourly earnings in that setting increase, but again, the effect is very small and only evident in some subgroups. Moreover, higher earnings in weekday-daytime practice reduce the probability of providing AHC, particularly for men. Increasing GPs' earnings appears to be at best relatively ineffective in encouraging increased provision of AHC and may even prove harmful if incentives are not well targeted. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  1. Tail shortening by discrete hydrodynamics

    NASA Astrophysics Data System (ADS)

    Kiefer, J.; Visscher, P. B.

    1982-02-01

    A discrete formulation of hydrodynamics was recently introduced, whose most important feature is that it is exactly renormalizable. Previous numerical work has found that it provides a more efficient and rapidly convergent method for calculating transport coefficients than the usual Green-Kubo method. The latter's convergence difficulties are due to the well-known "long-time tail" of the time correlation function which must be integrated over time. The purpose of the present paper is to present additional evidence that these difficulties are really absent in the discrete equation of motion approach. The "memory" terms in the equation of motion are calculated accurately, and shown to decay much more rapidly with time than the equilibrium time correlations do.

  2. Is the Nintendo Wii Fit really acceptable to older people?: a discrete choice experiment

    PubMed Central

    2011-01-01

    Background Interactive video games such as the Nintendo Wii Fit are increasingly used as a therapeutic tool in health and aged care settings however, their acceptability to older people is unclear. The aim of this study was to determine the acceptability of the Nintendo Wii Fit as a therapy tool for hospitalised older people using a discrete choice experiment (DCE) before and after exposure to the intervention. Methods A DCE was administered to 21 participants in an interview style format prior to, and following several sessions of using the Wii Fit in physiotherapy. The physiotherapist prescribed the Wii Fit activities, supervised and supported the patient during the therapy sessions. Attributes included in the DCE were: mode of therapy (traditional or using the Wii Fit), amount of therapy, cost of therapy program and percentage of recovery made. Data was analysed using conditional (fixed-effects) logistic regression. Results Prior to commencing the therapy program participants were most concerned about therapy time (avoiding programs that were too intensive), and the amount of recovery they would make. Following the therapy program, participants were more concerned with the mode of therapy and preferred traditional therapy programs over programs using the Wii Fit. Conclusions The usefulness of the Wii Fit as a therapy tool with hospitalised older people is limited not only by the small proportion of older people who are able to use it, but by older people's preferences for traditional approaches to therapy. Mainstream media portrayals of the popularity of the Wii Fit with older people may not reflect the true acceptability in the older hospitalised population. PMID:22011360

  3. Nonlinear Socio-Ecological Dynamics and First Principles ofCollective Choice Behavior of ``Homo Socialis"

    NASA Astrophysics Data System (ADS)

    Sonis, M.

    Socio-ecological dynamics emerged from the field of Mathematical SocialSciences and opened up avenues for re-examination of classical problems of collective behavior in Social and Spatial sciences. The ``engine" of this collective behavior is the subjective mental evaluation of level of utilities in the future, presenting sets of composite socio-economic-temporal-locational advantages. These dynamics present new laws of collective multi-population behavior which are the meso-level counterparts of the utility optimization individual behavior. The central core of the socio-ecological choice dynamics includes the following first principle of the collective choice behavior of ``Homo Socialis" based on the existence of ``collective consciousness": the choice behavior of ``Homo Socialis" is a collective meso-level choice behavior such that the relative changes in choice frequencies depend on the distribution of innovation alternatives between adopters of innovations. The mathematical basis of the Socio-Ecological Dynamics includes two complementary analytical approaches both based on the use of computer modeling as a theoretical and simulation tool. First approach is the ``continuous approach" --- the systems of ordinary and partial differential equations reflecting the continuous time Volterra ecological formalism in a form of antagonistic and/or cooperative collective hyper-games between different sub-sets of choice alternatives. Second approach is the ``discrete approach" --- systems of difference equations presenting a new branch of the non-linear discrete dynamics --- the Discrete Relative m-population/n-innovations Socio-Spatial Dynamics (Dendrinos and Sonis, 1990). The generalization of the Volterra formalism leads further to the meso-level variational principle of collective choice behavior determining the balance between the resulting cumulative social spatio-temporal interactions among the population of adopters susceptible to the choice alternatives and the

  4. Job Preferences of Nurses and Midwives for Taking Up a Rural Job in Peru: A Discrete Choice Experiment

    PubMed Central

    Huicho, Luis; Miranda, J. Jaime; Diez-Canseco, Francisco; Lema, Claudia; Lescano, Andrés G.; Lagarde, Mylene; Blaauw, Duane

    2012-01-01

    Background Robust evidence on interventions to improve the shortage of health workers in rural areas is needed. We assessed stated factors that would attract short-term contract nurses and midwives to work in a rural area of Peru. Methods and Findings A discrete choice experiment (DCE) was conducted to evaluate the job preferences of nurses and midwives currently working on a short-term contract in the public sector in Ayacucho, Peru. Job attributes, and their levels, were based on literature review, qualitative interviews and focus groups of local health personnel and policy makers. A labelled design with two choices, rural community or Ayacucho city, was used. Job attributes were tailored to these settings. Multiple conditional logistic regressions were used to assess the determinants of job preferences. Then we used the best-fitting estimated model to predict the impact of potential policy incentives on the probability of choosing a rural job or a job in Ayacucho city. We studied 205 nurses and midwives. The odds of choosing an urban post was 14.74 times than that of choosing a rural one. Salary increase, health center-type of facility and scholarship for specialization were preferred attributes for choosing a rural job. Increased number of years before securing a permanent contract acted as a disincentive for both rural and urban jobs. Policy simulations showed that the most effective attraction package to uptake a rural job included a 75% increase in salary plus scholarship for a specialization, which would increase the proportion of health workers taking a rural job from 36.4% up to 60%. Conclusions Urban jobs were more strongly preferred than rural ones. However, combined financial and non-financial incentives could almost double rural job uptake by nurses and midwifes. These packages may provide meaningful attraction strategies to rural areas and should be considered by policy makers for implementation. PMID:23284636

  5. Financial incentives to discontinue long-term benzodiazepine use: a discrete choice experiment investigating patient preferences and willingness to participate.

    PubMed

    Marti, Joachim; Bachhuber, Marcus; Feingold, Jordyn; Meads, David; Richards, Michael; Hennessy, Sean

    2017-10-06

    Investigate the acceptability of financial incentives for initiating a medically supervised benzodiazepine discontinuation programme among people with long-term benzodiazepine use and to identify programme features that influence willingness to participate. We conducted a discrete choice experiment in which we presented a variety of incentive-based programs to a sample of older adults with long-term benzodiazepine use identified using the outpatient electronic health record of a university-owned health system. We studied four programme variables: incentive amount for initiating the programme, incentive amount for successful benzodiazepine discontinuation, lottery versus certain payment and whether partial payment was given for dose reduction. Respondents reported their willingness to participate in the programmes and additional information was collected on demographics, history of use and anxiety symptoms. The overall response rate was 28.4%. Among the 126 respondents, all four programme variables influenced stated preferences. Respondents strongly preferred guaranteed cash-based incentives as opposed to a lottery, and the dollar amount of both the starting and conditional incentives had a substantial impact on choice. Willingness to participate increased with the amount of conditional incentive. Programme participation also varied by gender, duration of use and income. Participation in an incentive-based benzodiazepine discontinuation programme might be relatively low, but is modifiable by programme variables including incentive amounts. These results will be helpful to inform the design of future trials of benzodiazepine discontinuation programmes. Further research is needed to assess the financial viability and potential cost-effectiveness of such economic incentives. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  6. Incorporating social impact on new product adoption in choice modeing: A case study in green vehicles

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    He, Lin; Wang, Mingxian; Chen, Wei

    While discrete choice analysis is prevalent in capturing consumer preferences and describing their choice behaviors in product design, the traditional choice modeling approach assumes that each individual makes independent decisions, without considering the social impact. However, empirical studies show that choice is social - influenced by many factors beyond engineering performance of a product and consumer attributes. To alleviate this limitation, we propose a new choice modeling framework to capture the dynamic influence from social networks on consumer adoption of new products. By introducing social influence attributes into a choice utility function, social network simulation is integrated with the traditionalmore » discrete choice analysis in a three-stage process. Our study shows the need for considering social impact in forecasting new product adoption. Using hybrid electric vehicles as an example, our work illustrates the procedure of social network construction, social influence evaluation, and choice model estimation based on data from the National Household Travel Survey. Our study also demonstrates several interesting findings on the dynamic nature of new technology adoption and how social networks may influence hybrid electric vehicle adoption. (C) 2014 Elsevier Ltd. All rights reserved« less

  7. Discrete event simulation model for external yard choice of import container terminal in a port buffer area

    NASA Astrophysics Data System (ADS)

    Rusgiyarto, Ferry; Sjafruddin, Ade; Frazila, Russ Bona; Suprayogi

    2017-06-01

    Increasing container traffic and land acquisition problem for terminal expansion leads to usage of external yard in a port buffer area. This condition influenced the terminal performance because a road which connects the terminal and the external yard was also used by non-container traffic. Location choice problem considered to solve this condition, but the previous research has not taken account a stochastic condition of container arrival rate and service time yet. Bi-level programming framework was used to find optimum location configuration. In the lower-level, there was a problem to construct the equation, which correlated the terminal operation and the road due to different time cycle equilibrium. Container moves from the quay to a terminal gate in a daily unit of time, meanwhile, it moves from the terminal gate to the external yard through the road in a minute unit of time. If the equation formulated in hourly unit equilibrium, it cannot catch up the container movement characteristics in the terminal. Meanwhile, if the equation formulated in daily unit equilibrium, it cannot catch up the road traffic movement characteristics in the road. This problem can be addressed using simulation model. Discrete Event Simulation Model was used to simulate import container flow processes in the container terminal and external yard. Optimum location configuration in the upper-level was the combinatorial problem, which was solved by Full Enumeration approach. The objective function of the external yard location model was to minimize user transport cost (or time) and to maximize operator benefit. Numerical experiment was run for the scenario assumption of two container handling ways, three external yards, and thirty-day simulation periods. Jakarta International Container Terminal (JICT) container characteristics data was referred for the simulation. Based on five runs which were 5, 10, 15, 20, and 30 repetitions, operation one of three available external yards (external yard

  8. Using Decision Trees for Estimating Mode Choice of Trips in Buca-Izmir

    NASA Astrophysics Data System (ADS)

    Oral, L. O.; Tecim, V.

    2013-05-01

    Decision makers develop transportation plans and models for providing sustainable transport systems in urban areas. Mode Choice is one of the stages in transportation modelling. Data mining techniques can discover factors affecting the mode choice. These techniques can be applied with knowledge process approach. In this study a data mining process model is applied to determine the factors affecting the mode choice with decision trees techniques by considering individual trip behaviours from household survey data collected within Izmir Transportation Master Plan. From this perspective transport mode choice problem is solved on a case in district of Buca-Izmir, Turkey with CRISP-DM knowledge process model.

  9. What determines patient preferences for treating low risk basal cell carcinoma when comparing surgery vs imiquimod? A discrete choice experiment survey from the SINS trial.

    PubMed

    Tinelli, Michela; Ozolins, Mara; Bath-Hextall, Fiona; Williams, Hywel C

    2012-10-04

    The SINS trial (Controlled Clinical Trials ISRCTN48755084; Eudract No. 2004-004506-24) is a randomised controlled trial evaluating long term success of excisional surgery vs. imiquimod 5% cream for low risk nodular and superficial basal cell carcinoma (BCC). The trial included a discrete choice experiment questionnaire to explore patient preferences of a cream versus surgery for the treatment of their skin cancer. The self-completed questionnaire was administered at baseline to 183 participants, measuring patients' strength of preferences when choosing either alternative 'surgery' or 'imiquimod cream' instead of a fixed 'current situation' option (of surgical excision as standard practice in UK). The treatments were described according to: cost, chance of complete clearance, side effects and appearance. Participants had to choose between various scenarios. Analysis was performed using a mixed logit model, which took into account the impact of previous BCC treatment and sample preference variability. The analysis showed that respondents preferred 'imiquimod cream' to their 'current situation' or 'surgery', regardless of previous experience of BCC symptoms and treatment. Respondents were more likely to be worried about their cosmetic outcomes and side effects they might experience over and above their chance of clearance and cost. Those with no experience of surgery (compared with experience) valued more the choice of 'imiquimod cream' (£1013 vs £781). All treatment characteristics were significant determinants of treatment choice, and there was significant variability in the population preferences for all of them. Patients with BCC valued more 'imiquimod cream' than alternative 'surgery' options, and all treatment characteristics were important for their choice of care. Understanding how people with a BCC value alternative interventions may better inform the development of health care interventions.

  10. A Discrete Choice Experiment to Elicit Patient Willingness to Pay for Attributes of Treatment-Induced Symptom Relief in Comorbid. Insomnia.

    PubMed

    Roy, Anuja N; Madhavan, S Suresh; Lloyd, Andrew

    2015-04-01

    Insomnia is a burdensome, commonly comorbid condition. How patients value various aspects of the safety and efficacy of available drugs has not been studied. The aim of the present study was to quantify patient-rated utility by studying willingness to pay (WTP) for attributes of symptom relief via a discrete choice experiment (DCE). Adult primary care patients (West Virginia University Hospital) with comorbid insomnia were enrolled. The attributes and levels examined were sleep onset latency (SOL; 10, 20,30 minutes), awakenings (1, 2, 3), wake time after sleep onset (WASO; 15,45, 60 minutes), total sleep time (TST; 6, 7, 8 hours), hangover (none, mild, moderate), FDA-approved duration of use (short term, not restricted to short term, no restrictions), and out-of-pocket cost per month ($20, $35, $50). Willingness to pay (WTP) data were analyzed using a random effects binary logistic regression model. A total of 82 patients completed the DCE (74 analyzed). SOL, WASO, TST, and cost were all found to predict treatment choice. Higher values of SOL, WASO, and cost resulted in decreased preference for a particular treatment, while higher TST predicted increased preference. Modeling revealed an estimated marginal WTP of $66.69 for an example product that improved SOL by 10 minutes, reduced WASO by 15 minutes, and improved TST by 1 hour. Patient WTP for symptomatic relief in insomnia can help clinicians fine-tune interventions based on patient preferences, provide evidence for drug formulary and reimbursement decisions, and potentially guide the development of novel drugs.

  11. A Discrete Choice Experiment to Elicit Patient Willingness to Pay for Attributes of Treatment-Induced Symptom Relief in Comorbid Insomnia

    PubMed Central

    Roy, Anuja N.; Madhavan, S. Suresh; Lloyd, Andrew

    2016-01-01

    Purpose Insomnia is a burdensome, commonly comorbid condition. How patients value various aspects of the safety and efficacy of available drugs has not been studied. The aim of the present study was to quantify patient-rated utility by studying willingness to pay (WTP) for attributes of symptom relief via a discrete choice experiment (DCE). Methodology Adult primary care patients (West Virginia University Hospital) with comorbid insomnia were enrolled. The attributes and levels examined were sleep onset latency (SOL; 10, 20, 30 minutes), awakenings (1, 2, 3), wake time after sleep onset (WASO; 15, 45, 60 minutes), total sleep time (TST; 6, 7, 8 hours), hangover (none, mild, moderate), FDA-approved duration of use (short term, not restricted to short term, no restrictions), and out-of-pocket cost per month ($20, $35, $50). Willingness to pay (WTP) data were analyzed using a random effects binary logistic regression model. Results A total of 82 patients completed the DCE (74 analyzed). SOL, WASO, TST, and cost were all found to predict treatment choice. Higher values of SOL, WASO, and cost resulted in decreased preference for a particular treatment, while higher TST predicted increased preference. Modeling revealed an estimated marginal WTP of $66.69 for an example product that improved SOL by 10 minutes, reduced WASO by 15 minutes, and improved TST by 1 hour. Conclusion Patient WTP for symptomatic relief in insomnia can help clinicians fine-tune interventions based on patient preferences, provide evidence for drug formulary and reimbursement decisions, and potentially guide the development of novel drugs. PMID:26489177

  12. The association between general practitioner participation in joint teleconsultations and rates of referral: a discrete choice experiment.

    PubMed

    Cravo Oliveira, Tiago; Barlow, James; Bayer, Steffen

    2015-04-21

    Joint consultations - such as teleconsultations - provide opportunities for continuing education of general practitioners (GPs). It has been reported this form of interactive case-based learning may lead to fewer GP referrals, yet these studies have relied on expert opinion and simple frequencies, without accounting for other factors known to influence referrals. We use a survey-based discrete choice experiment of GPs' referral preferences to estimate how referral rates are associated with participation in joint teleconsultations, explicitly controlling for a number of potentially confounding variables. We distributed questionnaires at two meetings of the Portuguese Association of General Practice. GPs were presented with descriptions of patients with dermatological lesions and asked whether they would refer based on the waiting time, the distance to appointment, and pressure from patients for a referral. We analysed GPs' responses to multiple combinations of these factors, coupled with information on GP and practice characteristics, using a binary logit model. We estimated the probabilities of referral of different lesions using marginal effects. Questionnaires were returned by 44 GPs, giving a total of 721 referral choices. The average referral rate for the 11 GPs (25%) who had participated in teleconsultations was 68.1% (range 53-88%), compared to 74.4% (range 47-100%) for the remaining physicians. Participation in teleconsultations was associated with reductions in the probabilities of referral of 17.6% for patients presenting with keratosis (p = 0.02), 42.3% for psoriasis (p < 0.001), 8.4% for melanoma (p = 0.14), and 5.4% for naevus (p = 0.19). The results indicate that GP participation in teleconsultations is associated with overall reductions in referral rates and in variation across GPs, and that these effects are robust to the inclusion of other factors known to influence referrals. The reduction in range, coupled with different effects for different

  13. Substitution in recreation choice behavior

    Treesearch

    George L. Peterson; Daniel J. Stynes; Donald H. Rosenthal; John F. Dwyer

    1985-01-01

    This review discusses concepts and theories of substitution in recreation choice. It brings together the literature of recreation research, psychology, geography, economics, and transportation. Parallel and complementary developments need integration into an improved theory of substitution. Recreation decision behavior is characterized as a nested or sequential choice...

  14. A general gridding, discretization, and coarsening methodology for modeling flow in porous formations with discrete geological features

    NASA Astrophysics Data System (ADS)

    Karimi-Fard, M.; Durlofsky, L. J.

    2016-10-01

    A comprehensive framework for modeling flow in porous media containing thin, discrete features, which could be high-permeability fractures or low-permeability deformation bands, is presented. The key steps of the methodology are mesh generation, fine-grid discretization, upscaling, and coarse-grid discretization. Our specialized gridding technique combines a set of intersecting triangulated surfaces by constructing approximate intersections using existing edges. This procedure creates a conforming mesh of all surfaces, which defines the internal boundaries for the volumetric mesh. The flow equations are discretized on this conforming fine mesh using an optimized two-point flux finite-volume approximation. The resulting discrete model is represented by a list of control-volumes with associated positions and pore-volumes, and a list of cell-to-cell connections with associated transmissibilities. Coarse models are then constructed by the aggregation of fine-grid cells, and the transmissibilities between adjacent coarse cells are obtained using flow-based upscaling procedures. Through appropriate computation of fracture-matrix transmissibilities, a dual-continuum representation is obtained on the coarse scale in regions with connected fracture networks. The fine and coarse discrete models generated within the framework are compatible with any connectivity-based simulator. The applicability of the methodology is illustrated for several two- and three-dimensional examples. In particular, we consider gas production from naturally fractured low-permeability formations, and transport through complex fracture networks. In all cases, highly accurate solutions are obtained with significant model reduction.

  15. Managing Minor Ailments; The Public's Preferences for Attributes of Community Pharmacies. A Discrete Choice Experiment.

    PubMed

    Porteous, Terry; Ryan, Mandy; Bond, Christine; Watson, Margaret; Watson, Verity

    2016-01-01

    Demand for health services continues to rise. Greater use of community pharmacy services instead of medical services for minor ailments could help relieve pressure on healthcare providers in high-cost settings. Community pharmacies are recognised sources of treatment and advice for people wishing to manage these ailments. However, increasing the public's use of pharmacy services may depend on attributes of pharmacies and their staff. This study aimed to determine the general public's relative preferences for community pharmacy attributes using a discrete choice experiment (DCE). A UK-wide DCE survey of the general public was conducted using face-to-face computer-assisted personal interviews. Attributes and levels for the DCE were informed by a literature review and a cohort study of community pharmacy customers. The context for the experiment was a minor ailment scenario describing flu-like symptoms. The DCE choice sets described two hypothetical community pharmacy services; respondents were asked to choose which (if either) of the two pharmacies they would prefer to help them manage symptoms. Data from 1,049 interviews were analysed using an error components logit model. Willingness to pay (WTP), a monetary measure of benefit, was estimated for the different attribute levels. When seeking help or treatment for flu-like symptoms, respondents most valued a pharmacy service that would improve their understanding and management of symptoms (WTP = £6.28), provided by staff who are trained (WTP (pharmacist) = £2.63: WTP(trained assistant) = £3.22), friendly and approachable (WTP = £3.38). Waiting time, pharmacy location and availability of parking also contributed to respondents' preferences. WTP for a service comprising the best possible combination of attributes and levels was calculated as £55.43. Attributes of a community pharmacy and its staff may influence people's decisions about which pharmacy they would visit to access treatment and advice for minor

  16. Factors that influence clinicians' decisions to offer intravenous alteplase in acute ischemic stroke patients with uncertain treatment indication: Results of a discrete choice experiment.

    PubMed

    De Brún, Aoife; Flynn, Darren; Ternent, Laura; Price, Christopher I; Rodgers, Helen; Ford, Gary A; Rudd, Matthew; Lancsar, Emily; Simpson, Stephen; Teah, John; Thomson, Richard G

    2018-01-01

    Background Treatment with intravenous alteplase for eligible patients with acute ischemic stroke is underused, with variation in treatment rates across the UK. This study sought to elucidate factors influencing variation in clinicians' decision-making about this thrombolytic treatment. Methods A discrete choice experiment using hypothetical patient vignettes framed around areas of clinical uncertainty was conducted with UK-based clinicians. Mixed logit regression analyses were conducted on the data. Results A total of 138 clinicians completed the discrete choice experiment. Seven patient factors were individually predictive of increased likelihood of immediately offering IV alteplase (compared to reference levels in brackets): stroke onset time 2 h 30 min [50 min]; pre-stroke dependency mRS 3 [mRS 4]; systolic blood pressure 185 mm/Hg [140 mm/Hg]; stroke severity scores of NIHSS 5 without aphasia, NIHSS 14 and NIHSS 23 [NIHSS 2 without aphasia]; age 85 [68]; Afro-Caribbean [white]. Factors predictive of withholding treatment with IV alteplase were: age 95 [68]; stroke onset time of 4 h 15 min [50 min]; severe dementia [no memory problems]; SBP 200 mm/Hg [140 mm/Hg]. Three clinician-related factors were predictive of an increased likelihood of offering IV alteplase (perceived robustness of the evidence for IV alteplase; thrombolyzing more patients in the past 12 months; and high discomfort with uncertainty) and one with a decreased likelihood (high clinician comfort with treating patients outside the licensing criteria). Conclusions Both patient- and clinician-related factors have a major influence on the use of alteplase to treat patients with acute ischemic stroke. Clinicians' views of the evidence, comfort with uncertainty and treating patients outside the license criteria are important factors to address in programs that seek to reduce variation in care quality regarding treatment with IV alteplase. Further research is needed to further understand

  17. Investigating preferences for support with life after stroke: a discrete choice experiment.

    PubMed

    Burton, Christopher R; Fargher, Emily; Plumpton, Catrin; Roberts, Gwerfyl W; Owen, Heledd; Roberts, Eryl

    2014-02-08

    There is little evidence of service user preferences to guide the commissioning and improvement of services that support life after stroke. We report the first investigation of patients' and family carers' preferences for community services after stroke using a discrete choice experiment (DCE). Two workshops with patients and family carers (n = 8) explored stroke experiences, identifying attributes important in shaping views about service design, and piloted data collection strategies. Attributes were group versus individual support; service provider; additional support for social and leisure activities; and the total time required to access services. Patients and family carers were recruited six months post stroke-onset (mean 331 days) from four stroke services, and invited to participate in the DCE. Patients' general health (EQ5D) and functional dependence (Barthel Index) were also assessed. Of 474 eligible patients, 144 (30%) expressed an interest in the study, and 80 (56%) of these completed the survey questionnaire. 34 of 74 (46%) family carers recruited through patients completed the DCE. All four attributes were significant in shaping patients preferences for stroke support service delivery (p < 0.05), confirming the interpretation of workshop findings. Patients prefer help and support for emotional needs, communication problems and physical difficulties to be provided on an individual basis; and to be offered additional social and leisure activities that they are able to attend on their own. Patients would appear to prefer that voluntary organisations do not provide these services, although this may be linked to lack of experience of these services. Family carers would prefer help and support in their caring role on a one-to-one basis. Whilst health related quality of life is associated with preference for format of service, results were relatively consistent across sub-groups, with the exception of time since stroke, where social and leisure

  18. Analysis hierarchical model for discrete event systems

    NASA Astrophysics Data System (ADS)

    Ciortea, E. M.

    2015-11-01

    The This paper presents the hierarchical model based on discrete event network for robotic systems. Based on the hierarchical approach, Petri network is analysed as a network of the highest conceptual level and the lowest level of local control. For modelling and control of complex robotic systems using extended Petri nets. Such a system is structured, controlled and analysed in this paper by using Visual Object Net ++ package that is relatively simple and easy to use, and the results are shown as representations easy to interpret. The hierarchical structure of the robotic system is implemented on computers analysed using specialized programs. Implementation of hierarchical model discrete event systems, as a real-time operating system on a computer network connected via a serial bus is possible, where each computer is dedicated to local and Petri model of a subsystem global robotic system. Since Petri models are simplified to apply general computers, analysis, modelling, complex manufacturing systems control can be achieved using Petri nets. Discrete event systems is a pragmatic tool for modelling industrial systems. For system modelling using Petri nets because we have our system where discrete event. To highlight the auxiliary time Petri model using transport stream divided into hierarchical levels and sections are analysed successively. Proposed robotic system simulation using timed Petri, offers the opportunity to view the robotic time. Application of goods or robotic and transmission times obtained by measuring spot is obtained graphics showing the average time for transport activity, using the parameters sets of finished products. individually.

  19. Preferences for home- and community-based long-term care services in Germany: a discrete choice experiment.

    PubMed

    Lehnert, T; Günther, O H; Hajek, A; Riedel-Heller, S G; König, H H

    2018-04-06

    Most people prefer to "age in place" and to remain in their homes for as long as possible even in case they require long-term care. While informal care is projected to decrease in Germany, the use of home- and community-based services (HCBS) can be expected to increase in the future. Preference-based data on aspects of HCBS is needed to optimize person-centered care. To investigate preferences for home- and community-based long-term care services packages. Discrete choice experiment conducted in mailed survey. Randomly selected sample of the general population aged 45-64 years in Germany (n = 1.209). Preferences and marginal willingness to pay (WTP) for HCBS were assessed with respect to five HCBS attributes (with 2-4 levels): care time per day, service level of the HCBS provider, quality of care, number of different caregivers per month, co-payment. Quality of care was the most important attribute to respondents and small teams of regular caregivers (1-2) were preferred over larger teams. Yet, an extended range of services of the HCBS provider was not preferred over a more narrow range. WTP per hour of HCBS was €8.98. Our findings on preferences for HCBS in the general population in Germany add to the growing international evidence of preferences for LTC. In light of the great importance of high care quality to respondents, reimbursement for services by HCBS providers could be more strongly linked to the quality of services.

  20. Health worker preferences for community-based health insurance payment mechanisms: a discrete choice experiment

    PubMed Central

    2012-01-01

    Background In 2004, a community-based health insurance scheme (CBI) was introduced in Nouna health district, Burkina Faso. Since its inception, coverage has remained low and dropout rates high. One important reason for low coverage and high dropout is that health workers do not support the CBI scheme because they are dissatisfied with the provider payment mechanism of the CBI. Methods A discrete choice experiment (DCE) was used to examine CBI provider payment attributes that influence health workers’ stated preferences for payment mechanisms. The DCE was conducted among 176 health workers employed at one of the 34 primary care facilities or the district hospital in Nouna health district. Conditional logit models with main effects and interactions terms were used for analysis. Results Reimbursement of service fees (adjusted odds ratio (aOR) 1.49, p < 0.001) and CBI contributions for medical supplies and equipment (aOR 1.47, p < 0.001) had the strongest effect on whether the health workers chose a given provider payment mechanism. The odds of selecting a payment mechanism decreased significantly if the mechanism included (i) results-based financing (RBF) payments made through the local health management team (instead of directly to the health workers (aOR 0.86, p < 0.001)) or (ii) RBF payments based on CBI coverage achieved in the health worker’s facility relative to the coverage achieved at other facilities (instead of payments based on the numbers of individuals or households enrolled at the health worker’s facility (aOR 0.86, p < 0.001)). Conclusions Provider payment mechanisms can crucially determine CBI performance. Based on the results from this DCE, revised CBI payment mechanisms were introduced in Nouna health district in January 2011, taking into consideration health worker preferences on how they are paid. PMID:22697498

  1. Public preferences for interventions to prevent emerging infectious disease threats: a discrete choice experiment.

    PubMed

    Cook, Alex R; Zhao, Xiahong; Chen, Mark I C; Finkelstein, Eric A

    2018-02-16

    When faced with an emergent epidemic with high mortality and morbidity potential, policy makers must decide what public health interventions to deploy at different stages of the outbreak. However, almost nothing is known about how the public view these interventions or how they trade off risks (of disease) with inconvenience (of interventions). In this paper, we aim to understand public perceptions on pandemic interventions, as well as to identify if there are any distinct respondent preference classes. A discrete choice experiment. This study was fielded in Singapore between November 2012 and February 2013. A random sample of 500 Singapore residents aged 21 and over, including 271 women and 229 men, was analysed. Demographic information was collected from each participant. Participants were also shown a series of pairs of alternatives, each combining interventions and morbidity, mortality and cost outcomes and declared a preference for one combination. A random utility model was developed to determine the individual's preference for interventions and a hierarchical cluster analysis was performed to identify distinct respondent preference classes. On average, participants preferred more intense interventions, and preferred scenarios with fewer deaths and lower tax. The number of infections did not significantly influence respondents' responses. We identified two broad classes of respondents: those who were mortality averse and those who were expenditure averse. Education was found to be a predictor of group membership. Overall, there was considerable support for government interventions to prevent or mitigate outbreaks of emerging infectious diseases, including those that greatly restricted individual liberties, as long as the restrictions showed a reasonable chance of reducing the adverse health effects of the outbreak. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is

  2. Measuring the importance of health domains in psoriasis - discrete choice experiment versus rating scales.

    PubMed

    Gutknecht, Mandy; Schaarschmidt, Marthe-Lisa; Danner, Marion; Blome, Christine; Augustin, Matthias

    2018-01-01

    Psoriasis affects different aspects of health-related quality of life (eg, physical, psychological, and social impairments); these health domains can be of different importance for patients. The importance of domains can be measured with the Patient Benefit Index (PBI). This questionnaire weights the achievement of treatment goals by Likert scales (0, "not important at all" to 4, "very important") using the Patient Needs Questionnaire (PNQ). Treatment goals assessed with the PBI have been assigned to five health domains; the importance of each domain can be calculated as the average importance of the respective treatment goals. In this study, the PBI approach of deriving importance weights is contrasted to a discrete choice experiment (DCE), in order to determine the importance of health domains in psoriasis, and to find if the resulting weights will differ when derived from these two methods. Adult patients with psoriasis completed both questionnaires (PNQ, DCE). The PBI domains were used as attributes in the DCE with the levels "did not help at all", "helped moderately", and "helped a lot". Using DCE, "improving physical functioning" was the most important health domain, followed by "improving psychological well-being". Using PNQ, these domains were ranked in position two and three following "strengthening confidence in the therapy and in a possible healing". The latter was least important using DCE. The only agreement of ranking was shown in "reducing impairments due to therapy" (position four). "Improving social functioning" was ranked in position three (DCE) and five (PNQ). Health domains have different importance to patients with psoriasis. Using PNQ or DCE to determine the importance of domains results in markedly different rankings; both approaches can thus not be considered equivalent. However, in this study, importance was assessed at the domain level in DCE and at the single item level in PNQ, which may have added to the differences.

  3. Individual preferences for physical exercise as secondary prevention for non-specific low back pain: A discrete choice experiment.

    PubMed

    Aboagye, Emmanuel; Hagberg, Jan; Axén, Iben; Kwak, Lydia; Lohela-Karlsson, Malin; Skillgate, Eva; Dahlgren, Gunilla; Jensen, Irene

    2017-01-01

    Exercise is effective in improving non-specific low back pain (LBP). Certain components of physical exercise, such as the type, intensity and frequency of exercise, are likely to influence participation among working adults with non-specific LBP, but the value and relative importance of these components remain unknown. The study's aim was to examine such specific components and their influence on individual preferences for exercise for secondary prevention of non-specific LBP among working adults. In a discrete choice experiment, working individuals with non-specific LBP answered a web-based questionnaire. Each respondent was given ten pairs of hypothetical exercise programs and asked to choose one option from each pair. The choices comprised six attributes of exercise (i.e., type of training, design, intensity, frequency, proximity and incentives), each with either three or four levels. A conditional logit regression that reflected the random utility model was used to analyze the responses. The final study population consisted of 112 participants. The participants' preferred exercise option was aerobic (i.e., cardiovascular) rather than strength training, group exercise with trainer supervision, rather than individual or unsupervised exercise. They also preferred high intensity exercise performed at least once or twice per week. The most popular types of incentive were exercise during working hours and a wellness allowance rather than coupons for sports goods. The results show that the relative value of some attribute levels differed between young adults (age ≤ 44 years) and older adults (age ≥ 45 years) in terms of the level of trainer supervision required, exercise intensity, travel time to exercise location and financial incentives. For active study participants, exercise frequency (i.e., twice per week, 1.15; CI: 0.25; 2.06) influenced choice of exercise. For individuals with more than one child, travel time (i.e., 20 minutes, -0.55; CI: 0.65; 3.26) was

  4. Impact of peculiar features of construction of transport infrastructure on the choice of tools for reengineering of business processes

    NASA Astrophysics Data System (ADS)

    Khripko, Elena

    2017-10-01

    In the present article we study the issues of organizational resistance to reengineering of business processes in construction of transport infrastructure. Reengineering in a company of transport sector is, first and foremost, an innovative component of business strategy. We analyze the choice of forward and reverse reengineering tools and terms of their application in connection with organizational resistance. Reengineering is defined taking into account four aspects: fundamentality, radicality, abruptness, business process. We describe the stages of reengineering and analyze key requirements to newly created business processes.

  5. Discrete choice as a method for exploring education preferences in a Danish population of patients with type 2 diabetes.

    PubMed

    Schiøtz, Michaela; Bøgelund, Mette; Almdal, Thomas; Willaing, Ingrid

    2012-05-01

    To determine preferences among patients with type 2 diabetes for content and format of patient education. Using discrete choice methods, we surveyed patients about their preferences for patient education. We investigated preferred content and format regarding education on living well with diabetes, preventing complications, healthy eating, exercising, and psychosocial issues related to diabetes. We obtained usable responses from 2187 patients with type 2 diabetes. Acquiring competencies to live a fulfilling life with diabetes, adjust diet and exercise habits, and prevent complications was significantly more highly valued than was simply being informed about these topics. Patients preferred to be involved in the planning of their diabetes care and valued individually tailored content higher than prescheduled content. Women and younger patients found diet and exercise significantly more important than did men, and patients with poorly controlled diabetes valued all education and support more highly than did patients in better control. Patients with type 2 diabetes prefer to be actively involved in educational activities, to develop competencies to prevent and manage complications, and to involve their social network in supporting them. Future patient education should enhance participation and competence development and include relatives. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  6. A Bell-Curved Based Algorithm for Mixed Continuous and Discrete Structural Optimization

    NASA Technical Reports Server (NTRS)

    Kincaid, Rex K.; Weber, Michael; Sobieszczanski-Sobieski, Jaroslaw

    2001-01-01

    An evolutionary based strategy utilizing two normal distributions to generate children is developed to solve mixed integer nonlinear programming problems. This Bell-Curve Based (BCB) evolutionary algorithm is similar in spirit to (mu + mu) evolutionary strategies and evolutionary programs but with fewer parameters to adjust and no mechanism for self adaptation. First, a new version of BCB to solve purely discrete optimization problems is described and its performance tested against a tabu search code for an actuator placement problem. Next, the performance of a combined version of discrete and continuous BCB is tested on 2-dimensional shape problems and on a minimum weight hub design problem. In the latter case the discrete portion is the choice of the underlying beam shape (I, triangular, circular, rectangular, or U).

  7. A discrete choice experiment to obtain a tariff for valuing informal care situations measured with the CarerQol instrument.

    PubMed

    Hoefman, Renske J; van Exel, Job; Rose, John M; van de Wetering, E J; Brouwer, Werner B F

    2014-01-01

    Economic evaluations adopting a societal perspective need to include informal care whenever relevant. However, in practice, informal care is often neglected, because there are few validated instruments to measure and value informal care for inclusion in economic evaluations. The CarerQol, which is such an instrument, measures the impact of informal care on 7 important burden dimensions (CarerQol-7D) and values this in terms of general quality of life (CarerQol-VAS). The objective of the study was to calculate utility scores based on relative utility weights for the CarerQol-7D. These tariffs will facilitate inclusion of informal care in economic evaluations. The CarerQol-7D tariff was derived with a discrete choice experiment conducted as an Internet survey among the general adult population in the Netherlands (N = 992). The choice set contained 2 unlabeled alternatives described in terms of the 7 CarerQol-7D dimensions (level range: "no,"some," and "a lot"). An efficient experimental design with priors obtained from a pilot study (N = 104) was used. Data were analyzed with a panel mixed multinomial parameter model including main and interaction effects of the attributes. The utility attached to informal care situations was significantly higher when this situation was more attractive in terms of fewer problems and more fulfillment or support. The interaction term between the CarerQol-7D dimensions physical health and mental health problems also significantly explained this utility. The tariff was constructed by adding up the relative utility weights per category of all CarerQol-7D dimensions and the interaction term. We obtained a tariff providing standard utility scores for caring situations described with the CarerQol-7D. This facilitates the inclusion of informal care in economic evaluations.

  8. Verification of Three Dimensional Triangular Prismatic Discrete Ordinates Transport Code ENSEMBLE-TRIZ by Comparison with Monte Carlo Code GMVP

    NASA Astrophysics Data System (ADS)

    Homma, Yuto; Moriwaki, Hiroyuki; Ohki, Shigeo; Ikeda, Kazumi

    2014-06-01

    This paper deals with verification of three dimensional triangular prismatic discrete ordinates transport calculation code ENSEMBLE-TRIZ by comparison with multi-group Monte Carlo calculation code GMVP in a large fast breeder reactor. The reactor is a 750 MWe electric power sodium cooled reactor. Nuclear characteristics are calculated at beginning of cycle of an initial core and at beginning and end of cycle of equilibrium core. According to the calculations, the differences between the two methodologies are smaller than 0.0002 Δk in the multi-plication factor, relatively about 1% in the control rod reactivity, and 1% in the sodium void reactivity.

  9. Emotion regulation choice: the role of environmental affordances.

    PubMed

    Suri, Gaurav; Sheppes, Gal; Young, Gerald; Abraham, Damon; McRae, Kateri; Gross, James J

    2017-09-01

    Which emotion regulation strategy one uses in a given context can have profound affective, cognitive, and social consequences. It is therefore important to understand the determinants of emotion regulation choice. Many prior studies have examined person-specific, internal determinants of emotion regulation choice. Recently, it has become clear that external variables that are properties of the stimulus can also influence emotion regulation choice. In the present research, we consider whether reappraisal affordances, defined as the opportunities for re-interpretation of a stimulus that are inherent in that stimulus, can shape individuals' emotion regulation choices. We show that reappraisal affordances have stability across people and across time (Study 1), and are confounded with emotional intensity for a standardised set of picture stimuli (Study 2). Since emotional intensity has been shown to drive emotion regulation choice, we construct a context in which emotional intensity is separable from reappraisal affordances (Study 3) and use this context to show that reappraisal affordances powerfully influence emotion regulation choice even when emotional intensity and discrete emotions are taken into account (Study 4).

  10. Investigating Proenvironmental Behavior: The Case of Commuting Mode Choice

    NASA Astrophysics Data System (ADS)

    Trinh, Tu Anh; Phuong Linh Le, Thi

    2018-04-01

    The central aim of this article is to investigate mode choice behavior among commuters in Ho Chi Minh City using disaggregate mode choice model and norm activation theory. A better understanding of commuters’ choice of transport mode provide an opportunity to obtain valuable information on their travel behaviors which help to build a basic for proffering solutions stimulating commuters to switch to public transport, which in turn contribute to deal with traffic problems and environmental issues. Binary logistic regression was employed under disaggregate choice method. Key findings indicated that Demographic factors including Age (-0.308), Married (-9.089), Weather (-8.272); Trip factors including Travel cost (0.437), Travel distance (0.252), and Norm activation theory (Awareness of consequences: AC2 (-1.699), AC4 (2.951), AC6 (-3.523), AC7 (-2.092), AC9 (-3.045), AC11 (+ 2.939), and Personal norms: PN2 (-2.695)) had strong impact on the commuters’ mode choice. Although motorcycle was the major transport mode among commuters, they presented their willingness to switch to bus transport if it had less negative impacts on the environment and their daily living environment.

  11. Valuing EQ-5D-5L health states 'in context' using a discrete choice experiment.

    PubMed

    Cole, Amanda; Shah, Koonal; Mulhern, Brendan; Feng, Yan; Devlin, Nancy

    2018-05-01

    In health state valuation studies, health states are typically presented as a series of sentences, each describing a health dimension and severity 'level'. Differences in the severity levels can be subtle, and confusion about which is 'worse' can lead to logically inconsistent valuation data. A solution could be to mimic the way patients self-report health, where the ordinal structure of levels is clear. We develop and test the feasibility of presenting EQ-5D-5L health states in the 'context' of the entire EQ-5D-5L descriptive system. An online two-arm discrete choice experiment was conducted in the UK (n = 993). Respondents were randomly allocated to a control (standard presentation) or 'context' arm. Each respondent completed 16 paired comparison tasks and feedback questions about the tasks. Differences across arms were assessed using regression analyses. Presenting health states 'in context' can significantly reduce the selection of logically dominated health states, particularly for labels 'severe' and 'extreme' (χ 2  = 46.02, p < 0.001). Preferences differ significantly between arms (likelihood ratio statistic = 42.00, p < 0.05). Comparing conditional logit modeling results, coefficients are ordered as expected for both arms, but the magnitude of decrements between levels is larger for the context arm. Health state presentation is a key consideration in the design of valuation studies. Presenting health states 'in context' affects valuation data and reduces logical inconsistencies. Our results could have implications for other valuation tasks such as time trade-off, and for the valuation of other preference-based measures.

  12. Understanding HIV-positive patients' preferences for healthcare services: a protocol for a discrete choice experiment

    PubMed Central

    Youssef, Elaney; Cooper, Vanessa; Miners, Alec; Llewellyn, Carrie; Pollard, Alex; Lagarde, Mylene; Sachikonye, Memory; Sabin, Caroline; Foreman, Claire; Perry, Nicky; Nixon, Eileen; Fisher, Martin

    2016-01-01

    Introduction While the care of HIV-positive patients, including the detection and management of comorbidities, has historically been provided in HIV specialist outpatient clinics, recent years have seen a greater involvement of non-HIV specialists and general practitioners (GPs). The aim of this study is to determine whether patients would prefer to see their GP or HIV physician given general symptoms, and to understand what aspects of care influence their preferences. Methods/analysis We have developed and piloted a discrete choice experiment (DCE) to better understand patients' preferences for care of non-HIV-related acute symptoms. The design of the DCE was informed by our exploratory research, including the findings of a systematic literature review and a qualitative study. Additional questionnaire items have been included to measure demographics, service use and experience of non-HIV illnesses and quality of life (EQ5D). We plan to recruit 1000 patients from 14 HIV clinics across South East England. Data will be analysed using random-effects logistic regression and latent class analysis. ORs and 95% CIs will be used to estimate the relative importance of each of the attribute levels. Latent class analysis will identify whether particular groups of people value the service attribute levels differently. Ethics/dissemination Ethical approval for this study was obtained from the Newcastle and North Tyneside Research Ethics Committee (reference number 14/NE/1193). The results will be disseminated at national and international conferences and peer-reviewed publications. A study report, written in plain English, will be made available to all participants. The Patient Advisory Group will develop a strategy for wider dissemination of the findings to patients and the public. PMID:27431895

  13. Investigating the complementary value of discrete choice experiments for the evaluation of barriers and facilitators in implementation research: a questionnaire survey

    PubMed Central

    van Helvoort-Postulart, Debby; van der Weijden, Trudy; Dellaert, Benedict GC; de Kok, Mascha; von Meyenfeldt, Maarten F; Dirksen, Carmen D

    2009-01-01

    Background The potential barriers and facilitators to change should guide the choice of implementation strategy. Implementation researchers believe that existing methods for the evaluation of potential barriers and facilitators are not satisfactory. Discrete choice experiments (DCE) are relatively new in the health care sector to investigate preferences, and may be of value in the field of implementation research. The objective of our study was to investigate the complementary value of DCE for the evaluation of barriers and facilitators in implementation research. Methods Clinical subject was the implementation of the guideline for breast cancer surgery in day care. We identified 17 potential barriers and facilitators to the implementation of this guideline. We used a traditional questionnaire that was made up of statements about the potential barriers and facilitators. Respondents answered 17 statements on a five-point scale ranging from one (fully disagree) to five (fully agree). The potential barriers and facilitators were included in the DCE as decision attributes. Data were gathered among anaesthesiologists, surgical oncologists, and breast care nurses by means of a paper-and-pencil questionnaire. Results The overall response was 10%. The most striking finding was that the responses to the traditional questionnaire hardly differentiated between barriers. Forty-seven percent of the respondents thought that DCE is an inappropriate method. These respondents considered DCE too difficult and too time-consuming. Unlike the traditional questionnaire, the results of a DCE provide implementation researchers and clinicians with a relative attribute importance ranking that can be used to prioritize potential barriers and facilitators to change, and hence to better fine-tune the implementation strategies to the specific problems and challenges of a particular implementation process. Conclusion The results of our DCE and traditional questionnaire would probably lead to

  14. Statistical Methods for the Analysis of Discrete Choice Experiments: A Report of the ISPOR Conjoint Analysis Good Research Practices Task Force.

    PubMed

    Hauber, A Brett; González, Juan Marcos; Groothuis-Oudshoorn, Catharina G M; Prior, Thomas; Marshall, Deborah A; Cunningham, Charles; IJzerman, Maarten J; Bridges, John F P

    2016-06-01

    Conjoint analysis is a stated-preference survey method that can be used to elicit responses that reveal preferences, priorities, and the relative importance of individual features associated with health care interventions or services. Conjoint analysis methods, particularly discrete choice experiments (DCEs), have been increasingly used to quantify preferences of patients, caregivers, physicians, and other stakeholders. Recent consensus-based guidance on good research practices, including two recent task force reports from the International Society for Pharmacoeconomics and Outcomes Research, has aided in improving the quality of conjoint analyses and DCEs in outcomes research. Nevertheless, uncertainty regarding good research practices for the statistical analysis of data from DCEs persists. There are multiple methods for analyzing DCE data. Understanding the characteristics and appropriate use of different analysis methods is critical to conducting a well-designed DCE study. This report will assist researchers in evaluating and selecting among alternative approaches to conducting statistical analysis of DCE data. We first present a simplistic DCE example and a simple method for using the resulting data. We then present a pedagogical example of a DCE and one of the most common approaches to analyzing data from such a question format-conditional logit. We then describe some common alternative methods for analyzing these data and the strengths and weaknesses of each alternative. We present the ESTIMATE checklist, which includes a list of questions to consider when justifying the choice of analysis method, describing the analysis, and interpreting the results. Copyright © 2016 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  15. 2004-2006 Puget Sound Traffic Choices Study | Transportation Secure Data

    Science.gov Websites

    Center | NREL 04-2006 Puget Sound Traffic Choices Study 2004-2006 Puget Sound Traffic Choices Study The 2004-2006 Puget Sound Traffic Choices Study tested the hypothesis that time-of-day variable Administration for a pilot project on congestion-based tolling. Methodology To test the hypothesis, the study

  16. Development of a Quantitative Decision Metric for Selecting the Most Suitable Discretization Method for SN Transport Problems

    NASA Astrophysics Data System (ADS)

    Schunert, Sebastian

    In this work we develop a quantitative decision metric for spatial discretization methods of the SN equations. The quantitative decision metric utilizes performance data from selected test problems for computing a fitness score that is used for the selection of the most suitable discretization method for a particular SN transport application. The fitness score is aggregated as a weighted geometric mean of single performance indicators representing various performance aspects relevant to the user. Thus, the fitness function can be adjusted to the particular needs of the code practitioner by adding/removing single performance indicators or changing their importance via the supplied weights. Within this work a special, broad class of methods is considered, referred to as nodal methods. This class is naturally comprised of the DGFEM methods of all function space families. Within this work it is also shown that the Higher Order Diamond Difference (HODD) method is a nodal method. Building on earlier findings that the Arbitrarily High Order Method of the Nodal type (AHOTN) is also a nodal method, a generalized finite-element framework is created to yield as special cases various methods that were developed independently using profoundly different formalisms. A selection of test problems related to a certain performance aspect are considered: an Method of Manufactured Solutions (MMS) test suite for assessing accuracy and execution time, Lathrop's test problem for assessing resilience against occurrence of negative fluxes, and a simple, homogeneous cube test problem to verify if a method possesses the thick diffusive limit. The contending methods are implemented as efficiently as possible under a common SN transport code framework to level the playing field for a fair comparison of their computational load. Numerical results are presented for all three test problems and a qualitative rating of each method's performance is provided for each aspect: accuracy

  17. Impact of falling reimbursement rates on physician preferences regarding drug therapy for osteoarthritis using a discrete choice experiment.

    PubMed

    Berchi, Celia; Degieux, Pierre; Halhol, Hafid; Danel, Brigitte; Bennani, Mohammed; Philippe, Caroline

    2016-04-01

    In the European context of falling reimbursement rates for some osteoarthritis (OA) treatments, we performed a study to determine whether the cost covered by patients influenced the decisions of their physicians' prescriptions for medication. The study involved 106 general practitioners (GPs) and 82 rheumatologists. Preferences were elicited using a discrete choice experiment. Scenarios were generated including seven treatment attributes with associated different levels: pain relief, improvement in function, retardation of joint degradation, risk of moderate side effects, risk of serious side effects, cost borne by the patient and degree of patient acceptance of the treatment. OA treatment choices were significantly influenced by pain relief (β = 1.1533, P < 0.0001 for GPs and β = 0.5043, P = 0.0024 for rheumatologists), improvement in function (β = 1.2140 for GPs and β = 0.7192 for rheumatologists, P < 0.0001), annual cost to the patient (β = -0.0054 for GPs and β = -0.0038 for rheumatologists, P < 0.0001) and serious side effects (β = -0.5524 for GPs and β = -0.4268 for rheumatologists, P < 0.0001). The risk of moderate side effects only had an impact on GP decision making (β = 0.0282, P = 0.0028). All physicians were willing to make patients bear an extra annual cost of: (1) €225 among GPs and €189 among rheumatologists so that they could benefit from one unit improvement in function; and (2) €214 among GPs and €133 among rheumatologists so that they could benefit from a one unit improvement in pain relief. When making decisions about which treatment to prescribe, physicians take into account the cost to patients. Changes in reimbursement rates for some OA treatments may lead to changes in prescribing practices. © 2015 Royal Pharmaceutical Society.

  18. Energy transport in weakly nonlinear wave systems with narrow frequency band excitation.

    PubMed

    Kartashova, Elena

    2012-10-01

    A novel discrete model (D model) is presented describing nonlinear wave interactions in systems with small and moderate nonlinearity under narrow frequency band excitation. It integrates in a single theoretical frame two mechanisms of energy transport between modes, namely, intermittency and energy cascade, and gives the conditions under which each regime will take place. Conditions for the formation of a cascade, cascade direction, conditions for cascade termination, etc., are given and depend strongly on the choice of excitation parameters. The energy spectra of a cascade may be computed, yielding discrete and continuous energy spectra. The model does not require statistical assumptions, as all effects are derived from the interaction of distinct modes. In the example given-surface water waves with dispersion function ω(2)=gk and small nonlinearity-the D model predicts asymmetrical growth of side-bands for Benjamin-Feir instability, while the transition from discrete to continuous energy spectrum, excitation parameters properly chosen, yields the saturated Phillips' power spectrum ~g(2)ω(-5). The D model can be applied to the experimental and theoretical study of numerous wave systems appearing in hydrodynamics, nonlinear optics, electrodynamics, plasma, convection theory, etc.

  19. Discrete Fracture Network Modeling and Simulation of Subsurface Transport for the Topopah Springs and Lava Flow Aquifers at Pahute Mesa, FY 15 Progress Report

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Makedonska, Nataliia; Kwicklis, Edward Michael; Birdsell, Kay Hanson

    This progress report for fiscal year 2015 (FY15) describes the development of discrete fracture network (DFN) models for Pahute Mesa. DFN models will be used to upscale parameters for simulations of subsurface flow and transport in fractured media in Pahute Mesa. The research focuses on modeling of groundwater flow and contaminant transport using DFNs generated according to fracture characteristics observed in the Topopah Spring Aquifer (TSA) and the Lava Flow Aquifer (LFA). This work will improve the representation of radionuclide transport processes in large-scale, regulatory-focused models with a view to reduce pessimistic bounding approximations and provide more realistic contaminant boundarymore » calculations that can be used to describe the future extent of contaminated groundwater. Our goal is to refine a modeling approach that can translate parameters to larger-scale models that account for local-scale flow and transport processes, which tend to attenuate migration.« less

  20. Individual preferences for physical exercise as secondary prevention for non-specific low back pain: A discrete choice experiment

    PubMed Central

    Hagberg, Jan; Axén, Iben; Kwak, Lydia; Lohela-Karlsson, Malin; Skillgate, Eva; Dahlgren, Gunilla; Jensen, Irene

    2017-01-01

    Background Exercise is effective in improving non-specific low back pain (LBP). Certain components of physical exercise, such as the type, intensity and frequency of exercise, are likely to influence participation among working adults with non-specific LBP, but the value and relative importance of these components remain unknown. The study’s aim was to examine such specific components and their influence on individual preferences for exercise for secondary prevention of non-specific LBP among working adults. Methods In a discrete choice experiment, working individuals with non-specific LBP answered a web-based questionnaire. Each respondent was given ten pairs of hypothetical exercise programs and asked to choose one option from each pair. The choices comprised six attributes of exercise (i.e., type of training, design, intensity, frequency, proximity and incentives), each with either three or four levels. A conditional logit regression that reflected the random utility model was used to analyze the responses. Results The final study population consisted of 112 participants. The participants’ preferred exercise option was aerobic (i.e., cardiovascular) rather than strength training, group exercise with trainer supervision, rather than individual or unsupervised exercise. They also preferred high intensity exercise performed at least once or twice per week. The most popular types of incentive were exercise during working hours and a wellness allowance rather than coupons for sports goods. The results show that the relative value of some attribute levels differed between young adults (age ≤ 44 years) and older adults (age ≥ 45 years) in terms of the level of trainer supervision required, exercise intensity, travel time to exercise location and financial incentives. For active study participants, exercise frequency (i.e., twice per week, 1.15; CI: 0.25; 2.06) influenced choice of exercise. For individuals with more than one child, travel time (i.e., 20 minutes

  1. A preference-ordered discrete-gaming approach to air-combat analysis

    NASA Technical Reports Server (NTRS)

    Kelley, H. J.; Lefton, L.

    1978-01-01

    An approach to one-on-one air-combat analysis is described which employs discrete gaming of a parameterized model featuring choice between several closed-loop control policies. A preference-ordering formulation due to Falco is applied to rational choice between outcomes: win, loss, mutual capture, purposeful disengagement, draw. Approximate optimization is provided by an active-cell scheme similar to Falco's obtained by a 'backing up' process similar to that of Kopp. The approach is designed primarily for short-duration duels between craft with large-envelope weaponry. Some illustrative computations are presented for an example modeled using constant-speed vehicles and very rough estimation of energy shifts.

  2. Public preferences for establishing nephrology facilities in Greenland: estimating willingness-to-pay using a discrete choice experiment.

    PubMed

    Kjær, Trine; Bech, Mickael; Kronborg, Christian; Mørkbak, Morten Raun

    2013-10-01

    At present there are no nephrology facilities in Greenland. Greenlandic patients with renal failure needing dialysis thus have to travel to Denmark to obtain treatment. For patients in haemodialysis this necessitates a permanent residence in Denmark. Our study was aimed at examining Greenlanders' preferences for establishing nephrology facilities in Greenland at Queen Ingrid's Hospital in Nuuk, and to estimate the associated change in welfare. Preferences were elicited using a discrete choice experiment (DCE). A random sample of 500 individuals of the general population was sent a postal questionnaire in which they were asked to consider the trade-offs of establishing nephrology facilities in Greenland as opposed to the current situation. This involved trading off the benefits of having such facilities in their home country against the costs of the intervention. Besides including a payment attribute described in terms of incremental tax payment, the DCE included two interventions attributes related to (1) the organisation of labour, and (2) the physical settings of the patients. Respondents succeeded in answering the DCE despite cultural and linguistic disparity. We found that all the included attributes had a significant effect on respondents' choices, and that respondents' answers to the DCE were in keeping with their values as stated in the questionnaire. DCE data was analyzed using a random parameter logit model reparametrized in willingness-to-pay space. The results showed that establishing facilities in Greenland were preferred to the current treatment in Denmark. The welfare estimate from the DCE, at DKK 18.74 million, exceeds the estimated annual costs of establishing treatment facilities for patients with chronic renal failure. Given the estimated confidence interval this result seems robust. Establishing facilities in Greenland therefore would appear to be welfare-improving, deriving positive net benefits. Despite the relatively narrow policy focus, we

  3. Accounting for Scale Heterogeneity in Healthcare-Related Discrete Choice Experiments when Comparing Stated Preferences: A Systematic Review.

    PubMed

    Wright, Stuart J; Vass, Caroline M; Sim, Gene; Burton, Michael; Fiebig, Denzil G; Payne, Katherine

    2018-02-28

    Scale heterogeneity, or differences in the error variance of choices, may account for a significant amount of the observed variation in the results of discrete choice experiments (DCEs) when comparing preferences between different groups of respondents. The aim of this study was to identify if, and how, scale heterogeneity has been addressed in healthcare DCEs that compare the preferences of different groups. A systematic review identified all healthcare DCEs published between 1990 and February 2016. The full-text of each DCE was then screened to identify studies that compared preferences using data generated from multiple groups. Data were extracted and tabulated on year of publication, samples compared, tests for scale heterogeneity, and analytical methods to account for scale heterogeneity. Narrative analysis was used to describe if, and how, scale heterogeneity was accounted for when preferences were compared. A total of 626 healthcare DCEs were identified. Of these 199 (32%) aimed to compare the preferences of different groups specified at the design stage, while 79 (13%) compared the preferences of groups identified at the analysis stage. Of the 278 included papers, 49 (18%) discussed potential scale issues, 18 (7%) used a formal method of analysis to account for scale between groups, and 2 (1%) accounted for scale differences between preference groups at the analysis stage. Scale heterogeneity was present in 65% (n = 13) of studies that tested for it. Analytical methods to test for scale heterogeneity included coefficient plots (n = 5, 2%), heteroscedastic conditional logit models (n = 6, 2%), Swait and Louviere tests (n = 4, 1%), generalised multinomial logit models (n = 5, 2%), and scale-adjusted latent class analysis (n = 2, 1%). Scale heterogeneity is a prevalent issue in healthcare DCEs. Despite this, few published DCEs have discussed such issues, and fewer still have used formal methods to identify and account for the impact of scale

  4. Adolescent, parent and societal preferences and willingness to pay for meningococcal B vaccine: A Discrete Choice Experiment.

    PubMed

    Marshall, H S; Chen, G; Clarke, M; Ratcliffe, J

    2016-01-27

    Meningococcal B (MenB) vaccines have been licensed in many countries with private purchase the only option until recently, when a funded programme was introduced in the UK. The aim of this study was to explore adolescent/parental values for a variety of salient vaccine attributes (cost, effectiveness, side effect profile) to assess preferences and willingness-to-pay (WTP) for a MenB vaccine. A national cross-sectional population study was conducted in Australia using Discrete Choice Experiment methodology to assess adolescent/parent/adult preferences for attributes related to MenB vaccine. 2003 adults and 502 adolescents completed the survey in 2013. The majority of participants were willing to be vaccinated with MenB vaccine with vaccination opt-out chosen by 11.9% of adolescents and parents, and 18.2% of non-parent adults. A mixed logit regression model examining adolescent/adult preferences indicated consistent findings; the higher the effectiveness, the longer the duration of protection, the less chance of adverse events and the lower the cost, the more likely respondents were to agree to vaccination. For an ideal MenB vaccine, including the most favoured level of each attribute summed together (90% effectiveness, 10 year duration, 1 injection, no adverse events) adolescents would pay AU$251.60 and parents AU$295.10. Adolescents and parents would pay AU$90.70 or AU$127.20 for 90% vaccine effectiveness vs AU$18.50 or AU$16.70 for 70% effectiveness and would want to be financially compensated for 50% effectiveness; pay AU$63.30 or AU$76.40 for 10 years protection; and pay AU$48.50 or AU$49.20 for no vaccine related adverse events. A slight fever post vaccination was a preferred choice with parents and adolescents willing to pay AU$9.60 or AU$12.30 for this attribute. Vaccine effectiveness, adverse events and duration of immunity are important drivers for parental and adolescent decisions about WTP for MenB vaccine and should be included in discussions on the

  5. Managing Minor Ailments; The Public’s Preferences for Attributes of Community Pharmacies. A Discrete Choice Experiment

    PubMed Central

    Ryan, Mandy; Bond, Christine; Watson, Margaret

    2016-01-01

    Background Demand for health services continues to rise. Greater use of community pharmacy services instead of medical services for minor ailments could help relieve pressure on healthcare providers in high-cost settings. Community pharmacies are recognised sources of treatment and advice for people wishing to manage these ailments. However, increasing the public’s use of pharmacy services may depend on attributes of pharmacies and their staff. This study aimed to determine the general public’s relative preferences for community pharmacy attributes using a discrete choice experiment (DCE). Method A UK-wide DCE survey of the general public was conducted using face-to-face computer-assisted personal interviews. Attributes and levels for the DCE were informed by a literature review and a cohort study of community pharmacy customers. The context for the experiment was a minor ailment scenario describing flu-like symptoms. The DCE choice sets described two hypothetical community pharmacy services; respondents were asked to choose which (if either) of the two pharmacies they would prefer to help them manage symptoms. Data from 1,049 interviews were analysed using an error components logit model. Willingness to pay (WTP), a monetary measure of benefit, was estimated for the different attribute levels. Results When seeking help or treatment for flu-like symptoms, respondents most valued a pharmacy service that would improve their understanding and management of symptoms (WTP = £6.28), provided by staff who are trained (WTP (pharmacist) = £2.63: WTP(trained assistant) = £3.22), friendly and approachable (WTP = £3.38). Waiting time, pharmacy location and availability of parking also contributed to respondents’ preferences. WTP for a service comprising the best possible combination of attributes and levels was calculated as £55.43. Conclusion Attributes of a community pharmacy and its staff may influence people’s decisions about which pharmacy they would visit to

  6. Anomalous transport in discrete arcs and simulation of double layers in a model auroral circuit

    NASA Technical Reports Server (NTRS)

    Smith, Robert A.

    1987-01-01

    The evolution and long-time stability of a double layer (DL) in a discrete auroral arc requires that the parallel current in the arc, which may be considered uniform at the source, be diverted within the arc to charge the flanks of the U-shaped double layer potential structure. A simple model is presented in which this current redistribution is effected by anomalous transport based on electrostatic lower hybrid waves driven by the flank structure itself. This process provides the limiting constraint on the double layer potential. The flank charging may be represented as that of a nonlinear transmission line. A simplified model circuit, in which the transmission line is represented by a nonlinear impedance in parallel with a variable resistor, is incorporated in a one-dimensional simulation model to give the current density at the DL boundaries. Results are presented for the scaling of the DL potential as a function of the width of the arc and the saturation efficiency of the lower hybrid instability mechanism.

  7. Anomalous transport in discrete arcs and simulation of double layers in a model auroral circuit

    NASA Technical Reports Server (NTRS)

    Smith, Robert A.

    1987-01-01

    The evolution and long-time stability of a double layer in a discrete auroral arc requires that the parallel current in the arc, which may be considered uniform at the source, be diverted within the arc to charge the flanks of the U-shaped double-layer potential structure. A simple model is presented in which this current re-distribution is effected by anomalous transport based on electrostatic lower hybrid waves driven by the flank structure itself. This process provides the limiting constraint on the double-layer potential. The flank charging may be represented as that of a nonlinear transmission. A simplified model circuit, in which the transmission line is represented by a nonlinear impedance in parallel with a variable resistor, is incorporated in a 1-d simulation model to give the current density at the DL boundaries. Results are presented for the scaling of the DL potential as a function of the width of the arc and the saturation efficiency of the lower hybrid instability mechanism.

  8. Understanding HIV-positive patients' preferences for healthcare services: a protocol for a discrete choice experiment.

    PubMed

    Youssef, Elaney; Cooper, Vanessa; Miners, Alec; Llewellyn, Carrie; Pollard, Alex; Lagarde, Mylene; Sachikonye, Memory; Sabin, Caroline; Foreman, Claire; Perry, Nicky; Nixon, Eileen; Fisher, Martin

    2016-07-18

    While the care of HIV-positive patients, including the detection and management of comorbidities, has historically been provided in HIV specialist outpatient clinics, recent years have seen a greater involvement of non-HIV specialists and general practitioners (GPs). The aim of this study is to determine whether patients would prefer to see their GP or HIV physician given general symptoms, and to understand what aspects of care influence their preferences. We have developed and piloted a discrete choice experiment (DCE) to better understand patients' preferences for care of non-HIV-related acute symptoms. The design of the DCE was informed by our exploratory research, including the findings of a systematic literature review and a qualitative study. Additional questionnaire items have been included to measure demographics, service use and experience of non-HIV illnesses and quality of life (EQ5D). We plan to recruit 1000 patients from 14 HIV clinics across South East England. Data will be analysed using random-effects logistic regression and latent class analysis. ORs and 95% CIs will be used to estimate the relative importance of each of the attribute levels. Latent class analysis will identify whether particular groups of people value the service attribute levels differently. Ethical approval for this study was obtained from the Newcastle and North Tyneside Research Ethics Committee (reference number 14/NE/1193). The results will be disseminated at national and international conferences and peer-reviewed publications. A study report, written in plain English, will be made available to all participants. The Patient Advisory Group will develop a strategy for wider dissemination of the findings to patients and the public. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  9. Economic considerations and patients' preferences affect treatment selection for patients with rheumatoid arthritis: a discrete choice experiment among European rheumatologists.

    PubMed

    Hifinger, M; Hiligsmann, M; Ramiro, S; Watson, V; Severens, J L; Fautrel, B; Uhlig, T; van Vollenhoven, R; Jacques, P; Detert, J; Canas da Silva, J; Scirè, C A; Berghea, F; Carmona, L; Péntek, M; Keat, A; Boonen, A

    2017-01-01

    To compare the value that rheumatologists across Europe attach to patients' preferences and economic aspects when choosing treatments for patients with rheumatoid arthritis. In a discrete choice experiment, European rheumatologists chose between two hypothetical drug treatments for a patient with moderate disease activity. Treatments differed in five attributes: efficacy (improvement and achieved state on disease activity), safety (probability of serious adverse events), patient's preference (level of agreement), medication costs and cost-effectiveness (incremental cost-effectiveness ratio (ICER)). A Bayesian efficient design defined 14 choice sets, and a random parameter logit model was used to estimate relative preferences for rheumatologists across countries. Cluster analyses and latent class models were applied to understand preference patterns across countries and among individual rheumatologists. Responses of 559 rheumatologists from 12 European countries were included in the analysis (49% females, mean age 48 years). In all countries, efficacy dominated treatment decisions followed by economic considerations and patients' preferences. Across countries, rheumatologists avoided selecting a treatment that patients disliked. Latent class models revealed four respondent profiles: one traded off all attributes except safety, and the remaining three classes disregarded ICER. Among individual rheumatologists, 57% disregarded ICER and these were more likely from Italy, Romania, Portugal or France, whereas 43% disregarded uncommon/rare side effects and were more likely from Belgium, Germany, Hungary, the Netherlands, Norway, Spain, Sweden or UK. Overall, European rheumatologists are willing to trade between treatment efficacy, patients' treatment preferences and economic considerations. However, the degree of trade-off differs between countries and among individuals. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted

  10. A Cognitive Diagnosis Model for Cognitively Based Multiple-Choice Options

    ERIC Educational Resources Information Center

    de la Torre, Jimmy

    2009-01-01

    Cognitive or skills diagnosis models are discrete latent variable models developed specifically for the purpose of identifying the presence or absence of multiple fine-grained skills. However, applications of these models typically involve dichotomous or dichotomized data, including data from multiple-choice (MC) assessments that are scored as…

  11. Think twice before you book? Modelling the choice of public vs private dentist in a choice experiment.

    PubMed

    Kiiskinen, Urpo; Suominen-Taipale, Anna Liisa; Cairns, John

    2010-06-01

    This study concerns the choice of primary dental service provider by consumers. If the health service delivery system allows individuals to choose between public-care providers or if complementary private services are available, it is typically assumed that utilisation is a three-stage decision process. The patient first makes a decision to seek care, and then chooses the service provider. The final stage, involving decisions over the amount and form of treatment, is not considered here. The paper reports a discrete choice experiment (DCE) designed to evaluate attributes affecting individuals' choice of dental-care provider. The feasibility of the DCE approach in modelling consumers' choice in the context of non-acute need for dental care is assessed. The aim is to test whether a separate two-stage logit, a multinomial logit, or a nested logit best fits the choice process of consumers. A nested logit model of indirect utility functions is estimated and inclusive value (IV) constraints are tested for modelling implications. The results show that non-trading behaviour has an impact on the choice of appropriate modelling technique, but is to some extent dependent on the choice of scenarios offered. It is concluded that for traders multinomial logit is appropriate, whereas for non-traders and on average the nested logit is the method supported by the analyses. The consistent finding in all subgroup analyses is that the traditional two-stage decision process is found to be implausible in the context of consumer's choice of dental-care provider.

  12. What do UK doctors in training value in a post? A discrete choice experiment.

    PubMed

    Cleland, Jennifer; Johnston, Peter; Watson, Verity; Krucien, Nicolas; Skåtun, Diane

    2016-02-01

    Many individual and job-related factors are known to influence medical careers decision making. Medical trainees' (residents) views of which characteristics of a training post are important to them have been extensively studied but how they trade-off these characteristics is under-researched. Such information is crucial for the development of effective policies to enhance recruitment and retention. Our aim was to investigate the strength of UK foundation doctors' and trainees' preferences for training post characteristics in terms of monetary value. We used an online questionnaire study incorporating a discrete choice experiment (DCE), distributed to foundation programme doctors and doctors in training across all specialty groups within three UK regions, in August-October 2013. The main outcome measures were monetary values for training-post characteristics, based on willingness to forgo and willingness to accept extra income for a change in each job characteristic, calculated from regression coefficients. The questionnaire was answered by 1323 trainees. Good working conditions were the most influential characteristics of a training position. Trainee doctors would need to be compensated by an additional 49.8% above the average earnings within their specialty to move from a post with good working conditions to one with poor working conditions. A training post with limited rather than good opportunities for one's spouse or partner would require compensation of 38.4% above the average earnings within their specialty. Trainees would require compensation of 30.8% above the average earnings within their specialty to move from a desirable to a less desirable locality. These preferences varied only to a limited extent according to individual characteristics. Trainees place most value on good working conditions, good opportunities for their partners and desirable geographical location when making career-related decisions. This intelligence can be used to develop alternative

  13. What do UK medical students value most in their careers? A discrete choice experiment.

    PubMed

    Cleland, Jennifer A; Johnston, Peter; Watson, Verity; Krucien, Nicolas; Skåtun, Diane

    2017-08-01

    Many individual- and job-related factors are known to influence medical careers decision making. Previous research has extensively studied medical trainees' (residents') and students' views of the factors that are important. However, how trainees and students trade off these factors at times of important careers-related decision making is under-researched. Information about trade-offs is crucial to the development of effective policies to enhance the recruitment and retention of junior doctors. Our aim was to investigate the strength of UK medical students' preferences for the characteristics of training posts in terms of monetary value. We distributed a paper questionnaire that included a discrete choice experiment (DCE) to final-year medical students in six diverse medical schools across the UK. The main outcome measure was the monetary value of training post characteristics, based on willingness to forgo and willingness to accept extra income for a change in each job characteristic calculated from regression coefficients. A total of 810 medical students answered the questionnaire. The presence of good working conditions was by far the most influential characteristic of a training position. Medical students consider that, as newly graduated doctors, they will require compensation of an additional 43.68% above average earnings to move from a post with excellent working conditions to one with poor working conditions. Female students value excellent working conditions more highly than male students, whereas older medical students value them less highly than younger students. Students on the point of completing medical school and starting postgraduate training value good working conditions significantly more than they value desirable geographical location, unit reputation, familiarity with the unit or opportunities for partners or spouses. This intelligence can be used to address the crisis in workforce staffing that has developed in the UK and opens up fruitful

  14. A Conditional Curie-Weiss Model for Stylized Multi-group Binary Choice with Social Interaction

    NASA Astrophysics Data System (ADS)

    Opoku, Alex Akwasi; Edusei, Kwame Owusu; Ansah, Richard Kwame

    2018-04-01

    This paper proposes a conditional Curie-Weiss model as a model for decision making in a stylized society made up of binary decision makers that face a particular dichotomous choice between two options. Following Brock and Durlauf (Discrete choice with social interaction I: theory, 1955), we set-up both socio-economic and statistical mechanical models for the choice problem. We point out when both the socio-economic and statistical mechanical models give rise to the same self-consistent equilibrium mean choice level(s). Phase diagram of the associated statistical mechanical model and its socio-economic implications are discussed.

  15. Job preferences among clinical officers in public sector facilities in rural Kenya: a discrete choice experiment.

    PubMed

    Takemura, Toshio; Kielmann, Karina; Blaauw, Duane

    2016-01-08

    Clinical officers (COs), a mid-level cadre of health worker, are the backbone of healthcare provision in rural Kenya. However, the vacancy rate for COs in rural primary healthcare facilities is high. Little is known about factors motivating COs' preferences for rural postings. A discrete choice experiment (DCE) questionnaire was used with 57 COs at public health facilities in nine districts of Nyanza Province, Kenya. The questionnaire was developed on the basis of formative qualitative interviews with COs (n = 5) and examined how five selected job attributes influenced COs' preferences for working in rural areas. Conditional logit models were employed to examine the relative importance of different job attributes. Analysis of the qualitative data revealed five important job attributes influencing COs' preferences: quality of the facility, educational opportunities, housing, monthly salary and promotion. Analysis of the DCE indicated that a 1-year guaranteed study leave after 3 years of service would have the greatest impact on retention, followed by good quality health facility infrastructure and equipment and a 30% salary increase. Sub-group analysis shows that younger COs demonstrated a significantly stronger preference for study leave than older COs. Female COs placed significantly higher value on promotion than male COs. Although both financial incentives and non-financial incentives were effective in motivating COs to stay in post, the study leave intervention was shown to have the strongest impact on COs' retention in our study. Further research is required to examine appropriate interventions at each career stage that might boost COs' professional identity and status but without leading to larger deficits in the availability of generalist COs.

  16. Factors that influence midwifery students in Ghana when deciding where to practice: a discrete choice experiment.

    PubMed

    Ageyi-Baffour, Peter; Rominski, Sarah; Nakua, Emmanuel; Gyakobo, Mawuli; Lori, Jody R

    2013-05-04

    Mal-distribution of the health workforce with a strong bias for urban living is a major constraint to expanding midwifery services in Ghana. According to the UN Millennium Development Goals (MDG) report, the high risk of dying in pregnancy or childbirth continues in Africa. Maternal death is currently estimated at 350 per 100,000, partially a reflection of the low rates of professional support during birth. Many women in rural areas of Ghana give birth alone or with a non-skilled attendant. Midwives are key healthcare providers in achieving the MDGs, specifically in reducing maternal mortality by three-quarters and reducing by two-thirds the under 5 child mortality rate by 2015. This quantitative research study used a computerized structured survey containing a discrete choice experiment (DCE) to quantify the importance of different incentives and policies to encourage service to deprived, rural and remote areas by upper-year midwifery students following graduation. Using a hierarchical Bayes procedure we estimated individual and mean utility parameters for two hundred and ninety eight third year midwifery students from two of the largest midwifery training schools in Ghana. Midwifery students in our sample identified: 1) study leave after two years of rural service; 2) an advanced work environment with reliable electricity, appropriate technology and a constant drug supply; and 3) superior housing (2 bedroom, 1 bathroom, kitchen, living room, not shared) as the top three motivating factors to accept a rural posting. Addressing the motivating factors for rural postings among midwifery students who are about to graduate and enter the workforce could significantly contribute to the current mal-distribution of the health workforce.

  17. Understanding transporter specificity and the discrete appearance of channel-like gating domains in transporters

    PubMed Central

    Diallinas, George

    2014-01-01

    Transporters are ubiquitous proteins mediating the translocation of solutes across cell membranes, a biological process involved in nutrition, signaling, neurotransmission, cell communication and drug uptake or efflux. Similarly to enzymes, most transporters have a single substrate binding-site and thus their activity follows Michaelis-Menten kinetics. Substrate binding elicits a series of structural changes, which produce a transporter conformer open toward the side opposite to the one from where the substrate was originally bound. This mechanism, involving alternate outward- and inward-facing transporter conformers, has gained significant support from structural, genetic, biochemical and biophysical approaches. Most transporters are specific for a given substrate or a group of substrates with similar chemical structure, but substrate specificity and/or affinity can vary dramatically, even among members of a transporter family that show high overall amino acid sequence and structural similarity. The current view is that transporter substrate affinity or specificity is determined by a small number of interactions a given solute can make within a specific binding site. However, genetic, biochemical and in silico modeling studies with the purine transporter UapA of the filamentous ascomycete Aspergillus nidulans have challenged this dogma. This review highlights results leading to a novel concept, stating that substrate specificity, but also transport kinetics and transporter turnover, are determined by subtle intramolecular interactions between a major substrate binding site and independent outward- or cytoplasmically-facing gating domains, analogous to those present in channels. This concept is supported by recent structural evidence from several, phylogenetically and functionally distinct transporter families. The significance of this concept is discussed in relationship to the role and potential exploitation of transporters in drug action. PMID:25309439

  18. A Deep Penetration Problem Calculation Using AETIUS:An Easy Modeling Discrete Ordinates Transport Code UsIng Unstructured Tetrahedral Mesh, Shared Memory Parallel

    NASA Astrophysics Data System (ADS)

    KIM, Jong Woon; LEE, Young-Ouk

    2017-09-01

    As computing power gets better and better, computer codes that use a deterministic method seem to be less useful than those using the Monte Carlo method. In addition, users do not like to think about space, angles, and energy discretization for deterministic codes. However, a deterministic method is still powerful in that we can obtain a solution of the flux throughout the problem, particularly as when particles can barely penetrate, such as in a deep penetration problem with small detection volumes. Recently, a new state-of-the-art discrete-ordinates code, ATTILA, was developed and has been widely used in several applications. ATTILA provides the capabilities to solve geometrically complex 3-D transport problems by using an unstructured tetrahedral mesh. Since 2009, we have been developing our own code by benchmarking ATTILA. AETIUS is a discrete ordinates code that uses an unstructured tetrahedral mesh such as ATTILA. For pre- and post- processing, Gmsh is used to generate an unstructured tetrahedral mesh by importing a CAD file (*.step) and visualizing the calculation results of AETIUS. Using a CAD tool, the geometry can be modeled very easily. In this paper, we describe a brief overview of AETIUS and provide numerical results from both AETIUS and a Monte Carlo code, MCNP5, in a deep penetration problem with small detection volumes. The results demonstrate the effectiveness and efficiency of AETIUS for such calculations.

  19. Tracking Second Thoughts: Continuous and Discrete Revision Processes during Visual Lexical Decision

    PubMed Central

    Barca, Laura; Pezzulo, Giovanni

    2015-01-01

    We studied the dynamics of lexical decisions by asking participants to categorize lexical and nonlexical stimuli and recording their mouse movements toward response buttons during the choice. In a previous report we revealed greater trajectory curvature and attraction to competitors for Low Frequency words and Pseudowords. This analysis did not clarify whether the trajectory curvature in the two conditions was due to a continuous dynamic competition between the response alternatives or if a discrete revision process (a "change of mind") took place during the choice from an initially selected response to the opposite one. To disentangle these two possibilities, here we analyse the velocity and acceleration profiles of mouse movements during the choice. Pseudowords' peak movement velocity occurred with 100ms delay with respect to words and Letters Strings. Acceleration profile for High and Low Frequency words and Letters Strings exhibited a butterfly plot with one acceleration peak at 400ms and one deceleration peak at 650ms. Differently, Pseudowords' acceleration profile had double positive peaks (at 400 and 600ms) followed by movement deceleration, in correspondence with changes in the decision from lexical to nonlexical response buttons. These results speak to different online processes during the categorization of Low Frequency words and Pseudowords, with a continuous competition process for the former and a discrete revision process for the latter. PMID:25699992

  20. A PREFERENCE-OPPORTUNITY-CHOICE FRAMEWORK WITH APPLICATIONS TO INTERGROUP FRIENDSHIP*

    PubMed Central

    Zeng, Zhen; Xie, Yu

    2009-01-01

    A longstanding objective of friendship research is to identify the effects of personal preference and structural opportunity on intergroup friendship choice. Although past studies have used various methods to separate preference from opportunity, researchers have not yet systematically compared the properties and implications of these methods. We put forward a general framework for discrete choice, where choice probability is specified as proportional to the product of preference and opportunity. To implement this framework, we propose a modification to the conditional logit model for estimating preference parameters free from the influence of opportunity structure. We then compare our approach to several alternative methods for separating preference and opportunity used in the friendship choice literature. As an empirical example, we test hypotheses of homophily and status asymmetry in friendship choice using data from the National Longitudinal Study of Adolescent Health. The example also demonstrates the approach of conducting a sensitivity analysis to examine how parameter estimates vary by specification of the opportunity structure. PMID:19569394

  1. Acceptability and Preferences for Hypothetical Rectal Microbicides among a Community Sample of Young Men Who Have Sex with Men and Transgender Women in Thailand: A Discrete Choice Experiment.

    PubMed

    Newman, Peter A; Cameron, Michael P; Roungprakhon, Surachet; Tepjan, Suchon; Scarpa, Riccardo

    2016-11-01

    Rectal microbicides (RMs) may offer substantial benefits in expanding HIV prevention options for key populations. From April to August 2013, we conducted Tablet-Assisted Survey Interviewing, including a discrete choice experiment, with participants recruited from gay entertainment venues and community-based organizations in Chiang Mai and Pattaya, Thailand. Among 408 participants, 74.5 % were young men who have sex with men, 25.5 % transgender women, with mean age = 24.3 years. One-third (35.5 %) had ≤9th grade education; 63.4 % engaged in sex work. Overall, 83.4 % reported they would definitely use a RM, with more than 2-fold higher odds of choice of a RM with 99 versus 50 % efficacy, and significantly higher odds of choosing gel versus suppository, intermittent versus daily dosing, and prescription versus over-the-counter. Sex workers were significantly more likely to use a RM immediately upon availability, with greater tolerance for moderate efficacy and daily dosing. Engaging key populations in assessing RM preferences may support biomedical research and evidence-informed interventions to optimize the effectiveness of RMs in HIV prevention.

  2. Exclusive queueing model including the choice of service windows

    NASA Astrophysics Data System (ADS)

    Tanaka, Masahiro; Yanagisawa, Daichi; Nishinari, Katsuhiro

    2018-01-01

    In a queueing system involving multiple service windows, choice behavior is a significant concern. This paper incorporates the choice of service windows into a queueing model with a floor represented by discrete cells. We contrived a logit-based choice algorithm for agents considering the numbers of agents and the distances to all service windows. Simulations were conducted with various parameters of agent choice preference for these two elements and for different floor configurations, including the floor length and the number of service windows. We investigated the model from the viewpoint of transit times and entrance block rates. The influences of the parameters on these factors were surveyed in detail and we determined that there are optimum floor lengths that minimize the transit times. In addition, we observed that the transit times were determined almost entirely by the entrance block rates. The results of the presented model are relevant to understanding queueing systems including the choice of service windows and can be employed to optimize facility design and floor management.

  3. Urban transportation: Perspectives on mobility and choice

    NASA Technical Reports Server (NTRS)

    Sincoff, M. Z. (Editor); Dajani, J. S. (Editor); Arnold, G. R.; Bird, J. W.; Brooks, C. M. (Editor); Cobb, W. E.; Cross, J. E.; Darby, L. F.; Erb, N. H.; Ficht, J. C.

    1974-01-01

    A study of urban transportation systems are presented characterized by intensive scrutiny of many ideas, philosophies, and academic perspectives. This report is intended to communicate some dimensions of the urban transportation problem to the general public.

  4. Characteristics of movement and factors affecting the choice of mode of transport of community on the bank of Musi River of Palembang City of South Sumatra

    NASA Astrophysics Data System (ADS)

    Arliansyah, Joni; Hartono, Yusuf; Hastuti, Yulia; Astuti, Rinna

    2017-11-01

    Palembang City is one of the cities having the largest river in Indonesia and it should be able to take advantage of river transportation as an alternative choice. Inadequate availability of river transport facilities and infrastructures makes the people prefer other modes of land transportation rather than using river transportation. In addition, the development planning of river transportation such as the development of river taxi is less successful because it is not yet based on the movement pattern of the origin of the community travel destination. Based on the above matter, this study was conducted. The aim of the study was to find out the characteristics and factors affecting the mode choice of the community living along the bank of Musi River of Palembang City to be the basis of the development of river transportation system in Palembang City. The selected modes were motorcycles, cars, city transports, and ketek (motorized boats). Survey of home interviews was conducted to determine the origin of the destination and characteristics of travel was conducted in 30 villages located on the banks of Musi River. Field survey was conducted to determine the conditions and types of existing river transportation facilities and services. The results show that only 5.3 % of the occurrence movement used river transportation, the rest used motorcycles (69.1%), urban transport (15.9 %) and cars (9.7%), with the travel range less than10 minutes and 10 - 20 minutes as much as 43.2 % and 29 % of the total trips. From the socioeconomic profile of the community, it is found that most of the people living along the Musi River have low and middle incomes with the largest types of jobs as workers, students, shop owner, and housewives. The peak movement time for the movement of river transport occurs at 7:00 - 8:00, 10:00 - 11:00 and 16:00 - 17:00 with the movement of origin of the destination of river transportation is known to be 50% at the traditional market center of Dermaga of

  5. Transport in simple networks described by an integrable discrete nonlinear Schrödinger equation.

    PubMed

    Nakamura, K; Sobirov, Z A; Matrasulov, D U; Sawada, S

    2011-08-01

    We elucidate the case in which the Ablowitz-Ladik (AL)-type discrete nonlinear Schrödinger equation (NLSE) on simple networks (e.g., star graphs and tree graphs) becomes completely integrable just as in the case of a simple one-dimensional (1D) discrete chain. The strength of cubic nonlinearity is different from bond to bond, and networks are assumed to have at least two semi-infinite bonds with one of them working as an incoming bond. The present work is a nontrivial extension of our preceding one [Sobirov et al., Phys. Rev. E 81, 066602 (2010)] on the continuum NLSE to the discrete case. We find (1) the solution on each bond is a part of the universal (bond-independent) AL soliton solution on the 1D discrete chain, but it is multiplied by the inverse of the square root of bond-dependent nonlinearity; (2) nonlinearities at individual bonds around each vertex must satisfy a sum rule; and (3) under findings 1 and 2, there exist an infinite number of constants of motion. As a practical issue, with the use of an AL soliton injected through the incoming bond, we obtain transmission probabilities inversely proportional to the strength of nonlinearity on the outgoing bonds.

  6. What influences where they seek care? Caregivers’ preferences for under-five child healthcare services in urban slums of Malawi: A discrete choice experiment

    PubMed Central

    Guda Obse, Amarech; Darker, Catherine; Biesma, Regien

    2018-01-01

    Access to and utilisation of quality healthcare promotes positive child health outcomes. However, to be optimally utilised, the healthcare system needs to be responsive to the expectations of the population it serves. Health systems in many sub-Saharan African countries, including Malawi, have historically focused on promoting access to health services by the rural poor. However, in the context of increasing urbanisation and consequent proliferation of urban slums, promoting health of children under five years of age in these settings is a public health imperative. We conducted a discrete choice experiment to determine the relative importance of health facility factors in seeking healthcare for childhood illnesses in urban slums of Malawi. Caregivers of children under five years of age were presented with choice cards that depicted two hypothetical health facilities using six health facility attributes: availability of medicines and supplies, thoroughness of physical examination of the child, attitude of health workers, cost, distance, and waiting time. Caregivers were asked to indicate the health facility they would prefer to use. A mixed logit model was used to estimate the relative importance of and willingness to pay (WTP) for health facility attributes. Attributes with greatest influence on choice were: availability of medicines and supplies (β = 0.842, p<0.001) and thorough examination of the child (β = 0.479, p <0.001) with WTP of MK3698.32 ($11) (95% CI: $8–$13) and MK2049.13 ($6) (95% CI: $3–$9) respectively. Respondents were willing to pay 1.8 and 2.4 times more for medicine availability over thorough examination and positive attitude of health workers respectively. Therefore, strengthening health service delivery system through investment in sustained availability of essential medicines and supplies, sufficient and competent health workforce with positive attitude and clinical discipline to undertake thorough examination, and reductions in waiting

  7. What influences where they seek care? Caregivers' preferences for under-five child healthcare services in urban slums of Malawi: A discrete choice experiment.

    PubMed

    Lungu, Edgar Arnold; Guda Obse, Amarech; Darker, Catherine; Biesma, Regien

    2018-01-01

    Access to and utilisation of quality healthcare promotes positive child health outcomes. However, to be optimally utilised, the healthcare system needs to be responsive to the expectations of the population it serves. Health systems in many sub-Saharan African countries, including Malawi, have historically focused on promoting access to health services by the rural poor. However, in the context of increasing urbanisation and consequent proliferation of urban slums, promoting health of children under five years of age in these settings is a public health imperative. We conducted a discrete choice experiment to determine the relative importance of health facility factors in seeking healthcare for childhood illnesses in urban slums of Malawi. Caregivers of children under five years of age were presented with choice cards that depicted two hypothetical health facilities using six health facility attributes: availability of medicines and supplies, thoroughness of physical examination of the child, attitude of health workers, cost, distance, and waiting time. Caregivers were asked to indicate the health facility they would prefer to use. A mixed logit model was used to estimate the relative importance of and willingness to pay (WTP) for health facility attributes. Attributes with greatest influence on choice were: availability of medicines and supplies (β = 0.842, p<0.001) and thorough examination of the child (β = 0.479, p <0.001) with WTP of MK3698.32 ($11) (95% CI: $8-$13) and MK2049.13 ($6) (95% CI: $3-$9) respectively. Respondents were willing to pay 1.8 and 2.4 times more for medicine availability over thorough examination and positive attitude of health workers respectively. Therefore, strengthening health service delivery system through investment in sustained availability of essential medicines and supplies, sufficient and competent health workforce with positive attitude and clinical discipline to undertake thorough examination, and reductions in waiting

  8. Differences in Waiting List Prioritization Preferences of Occupational Therapists, Elderly People, and Persons With Disabilities: A Discrete Choice Experiment.

    PubMed

    Raymond, Marie-Hélène; Demers, Louise; Feldman, Debbie Ehrmann

    2018-01-01

    To compare the preferences of occupational therapists, elderly people, and adults with disabilities regarding prioritization criteria for occupational therapy waiting lists in home care. Discrete choice experiment survey. Survey mailed to occupational therapists working in home care and community-dwelling elderly or disabled persons. A sample (N=714) of home-based occupational therapists (n=241), elderly persons from a bank of research participants (n=226), and adults with physical disabilities recruited through community organizations (n=247). Not applicable. The dependent variable was whether the referral scenario was prioritized or not in each question. The results were analyzed through logistic regression using conditional logit models. Prioritization preferences differed between groups (P<.001). Occupational therapists most strongly prioritized people who had a few falls (odds ratio vs no falls, 48.7), whereas elderly people and adults with disabilities most strongly prioritized people who were unable to enter and exit the home (odds ratio vs no difficulty entering and exiting the home, 30.8 for elderly people and 16.8 for persons with disabilities.) CONCLUSIONS: Our results highlight the gap between the priorities of home-based occupational therapists and their target clientele. Although further inquiry is needed to inform priority setting, the findings emphasize the importance of public or patient involvement in decisions on waiting list prioritization. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  9. Preferences for support services among adolescents and young adults with cancer or a blood disorder: a discrete choice experiment.

    PubMed

    Goodall, Stephen; King, Madeleine; Ewing, Jane; Smith, Narelle; Kenny, Patricia

    2012-10-01

    Life-threatening illnesses in young people are traumatic for patients and their families. Support services can help patients and families deal with various non-medical impacts of diagnosis, disease and treatment. The aim of this study was to determine which types of support are most valued by adolescents and young adults (AYA) with cancer or blood disorders and their families. A discrete choice experiment (DCE). Separate experiments were conducted with AYA and their carers. Completed surveys were returned by 83 patients and 78 carers. AYA preferred emotional support for themselves (either by counsellors and/or peers), emotional support for their family, financial support and assistance returning to school/work over services relating to cultural and spiritual needs. Covariate analysis indicated female AYA were more likely than males to prefer emotional support, while males were more likely to prefer assistance returning to work/school. Carers preferred emotional support for their AYA and assistance returning to school/work. Like AYA, they were indifferent about services relating to cultural and spiritual needs. Providing the types of support services that people prefer should maximise effectiveness. This study suggests that AYA patients require support services that included financial aid, assistance returning to work/study, emotional support for themselves and for their family. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  10. 3D unstructured-mesh radiation transport codes

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Morel, J.

    1997-12-31

    Three unstructured-mesh radiation transport codes are currently being developed at Los Alamos National Laboratory. The first code is ATTILA, which uses an unstructured tetrahedral mesh in conjunction with standard Sn (discrete-ordinates) angular discretization, standard multigroup energy discretization, and linear-discontinuous spatial differencing. ATTILA solves the standard first-order form of the transport equation using source iteration in conjunction with diffusion-synthetic acceleration of the within-group source iterations. DANTE is designed to run primarily on workstations. The second code is DANTE, which uses a hybrid finite-element mesh consisting of arbitrary combinations of hexahedra, wedges, pyramids, and tetrahedra. DANTE solves several second-order self-adjoint forms of the transport equation including the even-parity equation, the odd-parity equation, and a new equation called the self-adjoint angular flux equation. DANTE also offers three angular discretization options:more » $$S{_}n$$ (discrete-ordinates), $$P{_}n$$ (spherical harmonics), and $$SP{_}n$$ (simplified spherical harmonics). DANTE is designed to run primarily on massively parallel message-passing machines, such as the ASCI-Blue machines at LANL and LLNL. The third code is PERICLES, which uses the same hybrid finite-element mesh as DANTE, but solves the standard first-order form of the transport equation rather than a second-order self-adjoint form. DANTE uses a standard $$S{_}n$$ discretization in angle in conjunction with trilinear-discontinuous spatial differencing, and diffusion-synthetic acceleration of the within-group source iterations. PERICLES was initially designed to run on workstations, but a version for massively parallel message-passing machines will be built. The three codes will be described in detail and computational results will be presented.« less

  11. A latent class multiple constraint multiple discrete-continuous extreme value model of time use and goods consumption.

    DOT National Transportation Integrated Search

    2016-06-01

    This paper develops a microeconomic theory-based multiple discrete continuous choice model that considers: (a) that both goods consumption and time allocations (to work and non-work activities) enter separately as decision variables in the utility fu...

  12. Discrete particle noise in a nonlinearly saturated plasma

    NASA Astrophysics Data System (ADS)

    Jenkins, Thomas; Lee, W. W.

    2006-04-01

    Understanding discrete particle noise in an equilibrium plasma has been an important topic since the early days of particle-in- cell (PIC) simulation [1]. In this paper, particle noise in a nonlinearly saturated system is investigated. We investigate the usefulness of the fluctuation-dissipation theorem (FDT) in a regime where drift instabilities are nonlinearly saturated. We obtain excellent agreement between the simulation results and our theoretical predictions of the noise properties. It is found that discrete particle noise always enhances the particle and thermal transport in the plasma, in agreement with the second law of thermodynamics. [1] C.K. Birdsall and A.B. Langdon, Plasma Physics via Computer Simulation, McGraw-Hill, New York (1985).

  13. Factors affecting retention of allied health professionals working with people with disability in rural New South Wales, Australia: discrete choice experiment questionnaire development.

    PubMed

    Gallego, Gisselle; Dew, Angela; Bulkeley, Kim; Veitch, Craig; Lincoln, Michelle; Bundy, Anita; Brentnall, Jennie

    2015-04-21

    This paper describes the development of a discrete choice experiment (DCE) questionnaire to identify the factors (attributes) that allied health professionals (AHPs) working with people with disability identify as important to encouraging them to remain practising in rural areas. Focus groups and semi-structured interviews were conducted with 97 purposively selected service providers working with people with disability in rural New South Wales, Australia. Focus groups and interviews were digitally recorded, transcribed, and analysed using a modified grounded theory approach involving thematic analysis and constant comparison. Six attributes that may influence AHPs working with people with disability in rural areas to continue to do so were inductively identified: travel arrangements, work flexibility, professional support, professional development, remuneration, and autonomy of practice. The qualitative research information was combined with a policy review to define these retention factors and ensure that they are amenable to policy changes. The use of various qualitative research methods allowed the development of a policy-relevant DCE questionnaire that was grounded in the experience of the target population (AHPs).

  14. PEER REVIEW FOR THE CONSUMER VEHICLE CHOICE MODEL

    EPA Science Inventory

    The U.S. Environmental Protection Agency’s (EPA) Office of Transportation and Air Quality (OTAQ) has recently sponsored the development of a Consumer Vehicle Choice Model (CVCM) by the Oak Ridge National Laboratory (ORNL). The specification by OTAQ to ORNL for consumer choice mod...

  15. What are colorectal cancer survivors' preferences for dietary advice? A best-worst discrete choice experiment.

    PubMed

    Wright, Stuart J; Gibson, Debbie; Eden, Martin; Lal, Simon; Todd, Chris; Ness, Andy; Burden, Sorrel

    2017-12-01

    Studies on healthy lifestyle interventions in survivors of colorectal cancer have been disappointing, demonstrating only modest changes. This study aims to quantify people's preferences for different aspects of dietary intervention. A best-worst discrete choice experiment was designed and incorporated into a questionnaire including participants' characteristics and a self-assessment of lifestyle. The response rate was 68% and 179 questionnaires were analysed. When analysing aggregate preferences, the modes of information provision selected as the most preferred were "face-to-face" (willingness to pay (WTP) £63.97, p ≤ 0.001) and "telephone" (WTP £62.36, p < 0.001) discussions whereas group discussions were preferred least (WTP -£118.96, p ≤ 0.001). Scenarios that included hospitals were most preferred (WTP £17.94, p = 0.031), and the favoured provider was bowel cancer nurses (WTP £75.11, p ≤ 0.001). When investigating preference heterogeneity, three sub-groups were identified: Firstly, "technophiles" preferring email (WTP £239.60, p ≤ 0.001) were male, were younger and had fewer risk factors. Secondly, a "one-to-one" group had strong preference for interventions over the telephone or at their local doctors and were older (WTP £642.13, p ≤ 0.001). Finally, a "person-centred" group preferred face-to-face individual or group sessions (WTP £358.79, p < 0.001) and had a high risk lifestyle. For survivors of colorectal cancer, there is not one approach that suits all when it comes to providing dietary advice. This is important information to consider when planning healthy lifestyle interventions which include dietary advice for survivors of colorectal cancer. Aligning services to individuals' preferences has the potential to improve patient experience and outcomes by increasing uptake of healthy lifestyle advice services and promoting a more tailored approach to dietary modifications, acknowledging sub-groups of people within the total

  16. Risk as an attribute in discrete choice experiments: a systematic review of the literature.

    PubMed

    Harrison, Mark; Rigby, Dan; Vass, Caroline; Flynn, Terry; Louviere, Jordan; Payne, Katherine

    2014-01-01

    Discrete choice experiments (DCEs) are used to elicit preferences of current and future patients and healthcare professionals about how they value different aspects of healthcare. Risk is an integral part of most healthcare decisions. Despite the use of risk attributes in DCEs consistently being highlighted as an area for further research, current methods of incorporating risk attributes in DCEs have not been reviewed explicitly. This study aimed to systematically identify published healthcare DCEs that incorporated a risk attribute, summarise and appraise methods used to present and analyse risk attributes, and recommend best practice regarding including, analysing and transparently reporting the methodology supporting risk attributes in future DCEs. The Web of Science, MEDLINE, EMBASE, PsycINFO and Econlit databases were searched on 18 April 2013 for DCEs that included a risk attribute published since 1995, and on 23 April 2013 to identify studies assessing risk communication in the general (non-DCE) health literature. Healthcare-related DCEs with a risk attribute mentioned or suggested in the title/abstract were obtained and retained in the final review if a risk attribute meeting our definition was included. Extracted data were tabulated and critically appraised to summarise the quality of reporting, and the format, presentation and interpretation of the risk attribute were summarised. This review identified 117 healthcare DCEs that incorporated at least one risk attribute. Whilst there was some evidence of good practice incorporated into the presentation of risk attributes, little evidence was found that developing methods and recommendations from other disciplines about effective methods and validation of risk communication were systematically applied to DCEs. In general, the reviewed DCE studies did not thoroughly report the methodology supporting the explanation of risk in training materials, the impact of framing risk, or exploring the validity of risk

  17. Investigating attribute non-attendance and its consequences in choice experiments with latent class models.

    PubMed

    Lagarde, Mylene

    2013-05-01

    A growing literature, mainly from transport and environment economics, has started to explore whether respondents violate some of the axioms about individuals' preferences in Discrete Choice Experiments (DCEs) and use simple strategies to make their choices. One of these strategies, termed attribute non-attendance (ANA), consists in ignoring one or more attributes. Using data from a DCE administered to healthcare providers in Ghana to evaluate their potential resistance to changes in clinical guidelines, this study illustrates how latent class models can be used in a step-wise approach to account for all possible ANA strategies used by respondents and explore the consequences of such behaviours. Results show that less than 3% of respondents considered all attributes when choosing between the two hypothetical scenarios proposed, with a majority looking at only one or two attributes. Accounting for ANA strategies improved the goodness-of-fit of the model and affected the magnitude of some of the coefficient and willingness-to-pay estimates. However, there was no difference in the predicted probabilities of the model taking into account ANA and the standard approach. Although the latter result is reassuring about the ability of DCEs to produce unbiased policy guidance, it should be confirmed by other studies. Copyright © 2012 John Wiley & Sons, Ltd.

  18. Influence of transport uncertainty on annual mean and seasonal inversions of atmospheric CO2 data

    NASA Astrophysics Data System (ADS)

    Peylin, Philippe; Baker, David; Sarmiento, Jorge; Ciais, Philippe; Bousquet, Philippe

    2002-10-01

    Inversion methods are often used to estimate surface CO2 fluxes from atmospheric CO2 concentration measurements, given an atmospheric transport model to relate the two. The published estimates disagree strongly on the location of the main sources and sinks, however. Are these differences due to the different time spans considered, or are they artifacts of the method and data used? Here we assess the uncertainty in such estimates due to the choice of time discretization of the measurements and fluxes, the spatial resolution of the fluxes, and the transport model. A suite of 27 Bayesian least squares inversions has been run, given by varying the number of flux regions solved for (7, 12, and 17), the time discretization (annual/annual, annual/monthly, and monthly/monthly for the fluxes/data), and the transport model (TM2, TM3, and GCTM), while holding all other inversion details constant. The estimated fluxes from this ensemble of inversions for the land + ocean sum are stable over large zonal bands, but the spread in the results increases when considering the longitudinal flux distribution inside these bands. On average for 1990-1994 the inversions place a large CO2 uptake north of 30°N (3.2 ± 0.3 GtC yr-1), mostly over the land regions, with more in Eurasia than North America. The ocean fluxes are generally smaller than given by [1999], especially south of 15°S and in the global total, where they are less than half as large. A small uptake is found for the tropical land regions, suggesting that growth more than compensates for deforestation there. The results for the different transport models are consistent with their known mixing properties; the longitudinal pattern of their land biosphere rectifier, in particular, strongly influences the regional partitioning of the flux in the north. While differences between the transport models contribute significantly to the spread of the results, an equivalent or even larger spread is due to the time discretization method

  19. Phase computations and phase models for discrete molecular oscillators.

    PubMed

    Suvak, Onder; Demir, Alper

    2012-06-11

    Biochemical oscillators perform crucial functions in cells, e.g., they set up circadian clocks. The dynamical behavior of oscillators is best described and analyzed in terms of the scalar quantity, phase. A rigorous and useful definition for phase is based on the so-called isochrons of oscillators. Phase computation techniques for continuous oscillators that are based on isochrons have been used for characterizing the behavior of various types of oscillators under the influence of perturbations such as noise. In this article, we extend the applicability of these phase computation methods to biochemical oscillators as discrete molecular systems, upon the information obtained from a continuous-state approximation of such oscillators. In particular, we describe techniques for computing the instantaneous phase of discrete, molecular oscillators for stochastic simulation algorithm generated sample paths. We comment on the accuracies and derive certain measures for assessing the feasibilities of the proposed phase computation methods. Phase computation experiments on the sample paths of well-known biological oscillators validate our analyses. The impact of noise that arises from the discrete and random nature of the mechanisms that make up molecular oscillators can be characterized based on the phase computation techniques proposed in this article. The concept of isochrons is the natural choice upon which the phase notion of oscillators can be founded. The isochron-theoretic phase computation methods that we propose can be applied to discrete molecular oscillators of any dimension, provided that the oscillatory behavior observed in discrete-state does not vanish in a continuous-state approximation. Analysis of the full versatility of phase noise phenomena in molecular oscillators will be possible if a proper phase model theory is developed, without resorting to such approximations.

  20. High-order solution methods for grey discrete ordinates thermal radiative transfer

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Maginot, Peter G., E-mail: maginot1@llnl.gov; Ragusa, Jean C., E-mail: jean.ragusa@tamu.edu; Morel, Jim E., E-mail: morel@tamu.edu

    This work presents a solution methodology for solving the grey radiative transfer equations that is both spatially and temporally more accurate than the canonical radiative transfer solution technique of linear discontinuous finite element discretization in space with implicit Euler integration in time. We solve the grey radiative transfer equations by fully converging the nonlinear temperature dependence of the material specific heat, material opacities, and Planck function. The grey radiative transfer equations are discretized in space using arbitrary-order self-lumping discontinuous finite elements and integrated in time with arbitrary-order diagonally implicit Runge–Kutta time integration techniques. Iterative convergence of the radiation equation ismore » accelerated using a modified interior penalty diffusion operator to precondition the full discrete ordinates transport operator.« less

  1. High-order solution methods for grey discrete ordinates thermal radiative transfer

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Maginot, Peter G.; Ragusa, Jean C.; Morel, Jim E.

    This paper presents a solution methodology for solving the grey radiative transfer equations that is both spatially and temporally more accurate than the canonical radiative transfer solution technique of linear discontinuous finite element discretization in space with implicit Euler integration in time. We solve the grey radiative transfer equations by fully converging the nonlinear temperature dependence of the material specific heat, material opacities, and Planck function. The grey radiative transfer equations are discretized in space using arbitrary-order self-lumping discontinuous finite elements and integrated in time with arbitrary-order diagonally implicit Runge–Kutta time integration techniques. Iterative convergence of the radiation equation ismore » accelerated using a modified interior penalty diffusion operator to precondition the full discrete ordinates transport operator.« less

  2. High-order solution methods for grey discrete ordinates thermal radiative transfer

    DOE PAGES

    Maginot, Peter G.; Ragusa, Jean C.; Morel, Jim E.

    2016-09-29

    This paper presents a solution methodology for solving the grey radiative transfer equations that is both spatially and temporally more accurate than the canonical radiative transfer solution technique of linear discontinuous finite element discretization in space with implicit Euler integration in time. We solve the grey radiative transfer equations by fully converging the nonlinear temperature dependence of the material specific heat, material opacities, and Planck function. The grey radiative transfer equations are discretized in space using arbitrary-order self-lumping discontinuous finite elements and integrated in time with arbitrary-order diagonally implicit Runge–Kutta time integration techniques. Iterative convergence of the radiation equation ismore » accelerated using a modified interior penalty diffusion operator to precondition the full discrete ordinates transport operator.« less

  3. Flexible funding opportunities for transportation investments

    DOT National Transportation Integrated Search

    1996-01-01

    The Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA) broke significant ground in giving State and local : decisionmakers greater discretion in the use of Federal transportation dollars. In particular, ISTEAs flexible fund : program...

  4. Monte Carlo Transport for Electron Thermal Transport

    NASA Astrophysics Data System (ADS)

    Chenhall, Jeffrey; Cao, Duc; Moses, Gregory

    2015-11-01

    The iSNB (implicit Schurtz Nicolai Busquet multigroup electron thermal transport method of Cao et al. is adapted into a Monte Carlo transport method in order to better model the effects of non-local behavior. The end goal is a hybrid transport-diffusion method that combines Monte Carlo Transport with a discrete diffusion Monte Carlo (DDMC). The hybrid method will combine the efficiency of a diffusion method in short mean free path regions with the accuracy of a transport method in long mean free path regions. The Monte Carlo nature of the approach allows the algorithm to be massively parallelized. Work to date on the method will be presented. This work was supported by Sandia National Laboratory - Albuquerque and the University of Rochester Laboratory for Laser Energetics.

  5. Local bounds preserving stabilization for continuous Galerkin discretization of hyperbolic systems

    NASA Astrophysics Data System (ADS)

    Mabuza, Sibusiso; Shadid, John N.; Kuzmin, Dmitri

    2018-05-01

    The objective of this paper is to present a local bounds preserving stabilized finite element scheme for hyperbolic systems on unstructured meshes based on continuous Galerkin (CG) discretization in space. A CG semi-discrete scheme with low order artificial dissipation that satisfies the local extremum diminishing (LED) condition for systems is used to discretize a system of conservation equations in space. The low order artificial diffusion is based on approximate Riemann solvers for hyperbolic conservation laws. In this case we consider both Rusanov and Roe artificial diffusion operators. In the Rusanov case, two designs are considered, a nodal based diffusion operator and a local projection stabilization operator. The result is a discretization that is LED and has first order convergence behavior. To achieve high resolution, limited antidiffusion is added back to the semi-discrete form where the limiter is constructed from a linearity preserving local projection stabilization operator. The procedure follows the algebraic flux correction procedure usually used in flux corrected transport algorithms. To further deal with phase errors (or terracing) common in FCT type methods, high order background dissipation is added to the antidiffusive correction. The resulting stabilized semi-discrete scheme can be discretized in time using a wide variety of time integrators. Numerical examples involving nonlinear scalar Burgers equation, and several shock hydrodynamics simulations for the Euler system are considered to demonstrate the performance of the method. For time discretization, Crank-Nicolson scheme and backward Euler scheme are utilized.

  6. Using a Discrete Choice Conjoint Experiment to Engage Stakeholders in the Design of an Outpatient Children's Health Center.

    PubMed

    Cunningham, Charles E; Niccols, Alison; Rimas, Heather; Robicheau, Randi; Anderson, Colleen; DeVries, Bart

    2017-10-01

    To engage users in the design of a regional child and youth health center. The perspective of users should be an integral component of a patient-centered, evidence-based approach to the design of health facilities. We conducted a discrete choice conjoint experiment (DCE), a method from marketing research and health economics, as a component of a strategy to engage users in the preconstruction planning process. A sample of 467 participants (290 staff and 177 clients or community stakeholders) completed the DCE. Latent class analysis identified three segments with different design preferences. A group we termed an enhanced design (57%) segment preferred a fully featured facility with personal contacts at the start of visits (in-person check-in, personal waiting room notification, volunteer-assisted wayfinding, and visible security), a family resource center with a health librarian, and an outdoor playground equipped with covered heated pathways. The self-guided design segment (11%), in contrast, preferred a design allowing a more independent use of the facility (e.g., self-check-in at computer kiosks, color-coded wayfinding, and a self-guided family resource center). Designs affording privacy and personal contact with staff were important to the private design segment (32%). The theme and decor of the building was less important than interactive features and personal contacts. A DCE allowed us to engage users in the planning process by estimating the value of individual design elements, identifying segments with differing views, informing decisions regarding design trade-offs, and simulating user response to design options.

  7. A Systematic Review Comparing the Acceptability, Validity and Concordance of Discrete Choice Experiments and Best-Worst Scaling for Eliciting Preferences in Healthcare.

    PubMed

    Whitty, Jennifer A; Oliveira Gonçalves, Ana Sofia

    2018-06-01

    The aim of this study was to compare the acceptability, validity and concordance of discrete choice experiment (DCE) and best-worst scaling (BWS) stated preference approaches in health. A systematic search of EMBASE, Medline, AMED, PubMed, CINAHL, Cochrane Library and EconLit databases was undertaken in October to December 2016 without date restriction. Studies were included if they were published in English, presented empirical data related to the administration or findings of traditional format DCE and object-, profile- or multiprofile-case BWS, and were related to health. Study quality was assessed using the PREFS checklist. Fourteen articles describing 12 studies were included, comparing DCE with profile-case BWS (9 studies), DCE and multiprofile-case BWS (1 study), and profile- and multiprofile-case BWS (2 studies). Although limited and inconsistent, the balance of evidence suggests that preferences derived from DCE and profile-case BWS may not be concordant, regardless of the decision context. Preferences estimated from DCE and multiprofile-case BWS may be concordant (single study). Profile- and multiprofile-case BWS appear more statistically efficient than DCE, but no evidence is available to suggest they have a greater response efficiency. Little evidence suggests superior validity for one format over another. Participant acceptability may favour DCE, which had a lower self-reported task difficulty and was preferred over profile-case BWS in a priority setting but not necessarily in other decision contexts. DCE and profile-case BWS may be of equal validity but give different preference estimates regardless of the health context; thus, they may be measuring different constructs. Therefore, choice between methods is likely to be based on normative considerations related to coherence with theoretical frameworks and on pragmatic considerations related to ease of data collection.

  8. Australian Public Preferences for the Funding of New Health Technologies: A Comparison of Discrete Choice and Profile Case Best-Worst Scaling Methods.

    PubMed

    Whitty, Jennifer A; Ratcliffe, Julie; Chen, Gang; Scuffham, Paul A

    2014-07-01

    Ethical, economic, political, and legitimacy arguments support the consideration of public preferences in health technology decision making. The objective was to assess public preferences for funding new health technologies and to compare a profile case best-worst scaling (BWS) and traditional discrete choice experiment (DCE) method. An online survey consisting of a DCE and BWS task was completed by 930 adults recruited via an Internet panel. Respondents traded between 7 technology attributes. Participation quotas broadly reflected the population of Queensland, Australia, by gender and age. Choice data were analyzed using a generalized multinomial logit model. The findings from both the BWS and DCE were generally consistent in that respondents exhibited stronger preferences for technologies offering prevention or early diagnosis over other benefit types. Respondents also prioritized technologies that benefit younger people, larger numbers of people, those in rural areas, or indigenous Australians; that provide value for money; that have no available alternative; or that upgrade an existing technology. However, the relative preference weights and consequent preference orderings differed between the DCE and BWS models. Further, poor correlation between the DCE and BWS weights was observed. While only a minority of respondents reported difficulty completing either task (22.2% DCE, 31.9% BWS), the majority (72.6%) preferred the DCE over BWS task. This study provides reassurance that many criteria routinely used for technology decision making are considered to be relevant by the public. The findings clearly indicate the perceived importance of prevention and early diagnosis. The dissimilarity observed between DCE and profile case BWS weights is contrary to the findings of previous comparisons and raises uncertainty regarding the comparative merits of these stated preference methods in a priority-setting context. © The Author(s) 2014.

  9. The effectiveness of policy on consumer choices for private road passenger transport emissions reductions in six major economies

    NASA Astrophysics Data System (ADS)

    Mercure, J.-F.; Lam, A.

    2015-06-01

    The effectiveness of fiscal policy to influence vehicle purchases for emissions reductions in private passenger road transport depends on its ability to incentivise consumers to make choices oriented towards lower emissions vehicles. However, car purchase choices are known to be strongly socially determined, and this sector is highly diverse due to significant socio-economic differences between consumer groups. Here, we present a comprehensive dataset and analysis of the structure of the 2012 private passenger vehicle fleet-years in six major economies across the World (UK, USA, China, India, Japan and Brazil) in terms of price, engine size and emissions distributions. We argue that choices and aggregate elasticities of substitution can be predicted using this data, enabling us to evaluate the effectiveness of potential fiscal and technological change policies on fleet-year emissions reductions. We provide tools to do so based on the distributive structure of prices and emissions in segments of a diverse market, both for conventional as well as unconventional engine technologies. We find that markets differ significantly between nations, and that correlations between engine sizes, emissions and prices exist strongly in some markets and not strongly in others. We furthermore find that markets for unconventional engine technologies have patchy coverages of varying levels. These findings are interpreted in terms of policy strategy.

  10. Do labeled versus unlabeled treatments of alternatives' names influence stated choice outputs? Results from a mode choice study.

    PubMed

    Jin, Wen; Jiang, Hai; Liu, Yimin; Klampfl, Erica

    2017-01-01

    Discrete choice experiments have been widely applied to elicit behavioral preferences in the literature. In many of these experiments, the alternatives are named alternatives, meaning that they are naturally associated with specific names. For example, in a mode choice study, the alternatives can be associated with names such as car, taxi, bus, and subway. A fundamental issue that arises in stated choice experiments is whether to treat the alternatives' names as labels (that is, labeled treatment), or as attributes (that is, unlabeled treatment) in the design as well as the presentation phases of the choice sets. In this research, we investigate the impact of labeled versus unlabeled treatments of alternatives' names on the outcome of stated choice experiments, a question that has not been thoroughly investigated in the literature. Using results from a mode choice study, we find that the labeled or the unlabeled treatment of alternatives' names in either the design or the presentation phase of the choice experiment does not statistically affect the estimates of the coefficient parameters. We then proceed to measure the influence toward the willingness-to-pay (WTP) estimates. By using a random-effects model to relate the conditional WTP estimates to the socioeconomic characteristics of the individuals and the labeled versus unlabeled treatments of alternatives' names, we find that: a) Given the treatment of alternatives' names in the presentation phase, the treatment of alternatives' names in the design phase does not statistically affect the estimates of the WTP measures; and b) Given the treatment of alternatives' names in the design phase, the labeled treatment of alternatives' names in the presentation phase causes the corresponding WTP estimates to be slightly higher.

  11. Do labeled versus unlabeled treatments of alternatives’ names influence stated choice outputs? Results from a mode choice study

    PubMed Central

    Jin, Wen; Jiang, Hai; Liu, Yimin; Klampfl, Erica

    2017-01-01

    Discrete choice experiments have been widely applied to elicit behavioral preferences in the literature. In many of these experiments, the alternatives are named alternatives, meaning that they are naturally associated with specific names. For example, in a mode choice study, the alternatives can be associated with names such as car, taxi, bus, and subway. A fundamental issue that arises in stated choice experiments is whether to treat the alternatives’ names as labels (that is, labeled treatment), or as attributes (that is, unlabeled treatment) in the design as well as the presentation phases of the choice sets. In this research, we investigate the impact of labeled versus unlabeled treatments of alternatives’ names on the outcome of stated choice experiments, a question that has not been thoroughly investigated in the literature. Using results from a mode choice study, we find that the labeled or the unlabeled treatment of alternatives’ names in either the design or the presentation phase of the choice experiment does not statistically affect the estimates of the coefficient parameters. We then proceed to measure the influence toward the willingness-to-pay (WTP) estimates. By using a random-effects model to relate the conditional WTP estimates to the socioeconomic characteristics of the individuals and the labeled versus unlabeled treatments of alternatives’ names, we find that: a) Given the treatment of alternatives’ names in the presentation phase, the treatment of alternatives’ names in the design phase does not statistically affect the estimates of the WTP measures; and b) Given the treatment of alternatives’ names in the design phase, the labeled treatment of alternatives’ names in the presentation phase causes the corresponding WTP estimates to be slightly higher. PMID:28806764

  12. Discrete Trials Teaching

    ERIC Educational Resources Information Center

    Ghezzi, Patrick M.

    2007-01-01

    The advantages of emphasizing discrete trials "teaching" over discrete trials "training" are presented first, followed by a discussion of discrete trials as a method of teaching that emerged historically--and as a matter of necessity for difficult learners such as those with autism--from discrete trials as a method for laboratory research. The…

  13. Path integral measure and triangulation independence in discrete gravity

    NASA Astrophysics Data System (ADS)

    Dittrich, Bianca; Steinhaus, Sebastian

    2012-02-01

    A path integral measure for gravity should also preserve the fundamental symmetry of general relativity, which is diffeomorphism symmetry. In previous work, we argued that a successful implementation of this symmetry into discrete quantum gravity models would imply discretization independence. We therefore consider the requirement of triangulation independence for the measure in (linearized) Regge calculus, which is a discrete model for quantum gravity, appearing in the semi-classical limit of spin foam models. To this end we develop a technique to evaluate the linearized Regge action associated to Pachner moves in 3D and 4D and show that it has a simple, factorized structure. We succeed in finding a local measure for 3D (linearized) Regge calculus that leads to triangulation independence. This measure factor coincides with the asymptotics of the Ponzano Regge Model, a 3D spin foam model for gravity. We furthermore discuss to which extent one can find a triangulation independent measure for 4D Regge calculus and how such a measure would be related to a quantum model for 4D flat space. To this end, we also determine the dependence of classical Regge calculus on the choice of triangulation in 3D and 4D.

  14. Insurees' preferences in hospital choice-A population-based study.

    PubMed

    Schuldt, Johannes; Doktor, Anna; Lichters, Marcel; Vogt, Bodo; Robra, Bernt-Peter

    2017-10-01

    In Germany, the patient himself makes the choice for or against a health service provider. Hospital comparison websites offer him possibilities to inform himself before choosing. However, it remains unclear, how health care consumers use those websites, and there is little information about how preferences in hospital choice differ interpersonally. We conducted a Discrete-Choice-Experiment (DCE) on hospital choice with 1500 randomly selected participants (age 40-70) in three different German cities selecting four attributes for hospital vignettes. The analysis of the study draws on multilevel mixed effects logit regression analyses with the dependent variables: "chance to select a hospital" and "choice confidence". Subsequently, we performed a Latent-Class-Analysis to uncover consumer segments with distinct preferences. 590 of the questionnaires were evaluable. All four attributes of the hospital vignettes have a significant impact on hospital choice. The attribute "complication rate" exerts the highest impact on consumers' decisions and reported choice confidence. Latent-Class-Analysis results in one dominant consumer segment that considered the complication rate the most important decision criterion. Using DCE, we were able to show that the complication rate is an important trusted criterion in hospital choice to a large group of consumers. Our study supports current governmental efforts in Germany to concentrate the provision of specialized health care services. We suggest further national and cross-national research on the topic. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  15. Human X-chromosome inactivation pattern distributions fit a model of genetically influenced choice better than models of completely random choice

    PubMed Central

    Renault, Nisa K E; Pritchett, Sonja M; Howell, Robin E; Greer, Wenda L; Sapienza, Carmen; Ørstavik, Karen Helene; Hamilton, David C

    2013-01-01

    In eutherian mammals, one X-chromosome in every XX somatic cell is transcriptionally silenced through the process of X-chromosome inactivation (XCI). Females are thus functional mosaics, where some cells express genes from the paternal X, and the others from the maternal X. The relative abundance of the two cell populations (X-inactivation pattern, XIP) can have significant medical implications for some females. In mice, the ‘choice' of which X to inactivate, maternal or paternal, in each cell of the early embryo is genetically influenced. In humans, the timing of XCI choice and whether choice occurs completely randomly or under a genetic influence is debated. Here, we explore these questions by analysing the distribution of XIPs in large populations of normal females. Models were generated to predict XIP distributions resulting from completely random or genetically influenced choice. Each model describes the discrete primary distribution at the onset of XCI, and the continuous secondary distribution accounting for changes to the XIP as a result of development and ageing. Statistical methods are used to compare models with empirical data from Danish and Utah populations. A rigorous data treatment strategy maximises information content and allows for unbiased use of unphased XIP data. The Anderson–Darling goodness-of-fit statistics and likelihood ratio tests indicate that a model of genetically influenced XCI choice better fits the empirical data than models of completely random choice. PMID:23652377

  16. Phase computations and phase models for discrete molecular oscillators

    PubMed Central

    2012-01-01

    Background Biochemical oscillators perform crucial functions in cells, e.g., they set up circadian clocks. The dynamical behavior of oscillators is best described and analyzed in terms of the scalar quantity, phase. A rigorous and useful definition for phase is based on the so-called isochrons of oscillators. Phase computation techniques for continuous oscillators that are based on isochrons have been used for characterizing the behavior of various types of oscillators under the influence of perturbations such as noise. Results In this article, we extend the applicability of these phase computation methods to biochemical oscillators as discrete molecular systems, upon the information obtained from a continuous-state approximation of such oscillators. In particular, we describe techniques for computing the instantaneous phase of discrete, molecular oscillators for stochastic simulation algorithm generated sample paths. We comment on the accuracies and derive certain measures for assessing the feasibilities of the proposed phase computation methods. Phase computation experiments on the sample paths of well-known biological oscillators validate our analyses. Conclusions The impact of noise that arises from the discrete and random nature of the mechanisms that make up molecular oscillators can be characterized based on the phase computation techniques proposed in this article. The concept of isochrons is the natural choice upon which the phase notion of oscillators can be founded. The isochron-theoretic phase computation methods that we propose can be applied to discrete molecular oscillators of any dimension, provided that the oscillatory behavior observed in discrete-state does not vanish in a continuous-state approximation. Analysis of the full versatility of phase noise phenomena in molecular oscillators will be possible if a proper phase model theory is developed, without resorting to such approximations. PMID:22687330

  17. Relations among Spontaneous Preferences, Familiarized Preferences, and Novelty Effects: Measurements with Forced-Choice Techniques

    ERIC Educational Resources Information Center

    Civan, Andrea; Teller, Davida Y.; Palmer, John

    2005-01-01

    We here describe a discrete trial, forced-choice, combined spontaneous preference and novelty preference technique. In this technique, spontaneous preferences and familiarized (postfamiliarization) preferences are measured with the same stimulus pairs under closely parallel conditions. A variety of systematic stimulus variations were used in…

  18. Prescriber preferences for behavioural economics interventions to improve treatment of acute respiratory infections: a discrete choice experiment

    PubMed Central

    Gong, Cynthia L; Hay, Joel W; Meeker, Daniella; Doctor, Jason N

    2016-01-01

    Objective To elicit prescribers' preferences for behavioural economics interventions designed to reduce inappropriate antibiotic prescribing, and compare these to actual behaviour. Design Discrete choice experiment (DCE). Setting 47 primary care centres in Boston and Los Angeles. Participants 234 primary care providers, with an average 20 years of practice. Main outcomes and measures Results of a behavioural economic intervention trial were compared to prescribers' stated preferences for the same interventions relative to monetary and time rewards for improved prescribing outcomes. In the randomised controlled trial (RCT) component, the 3 computerised prescription order entry-triggered interventions studied included: Suggested Alternatives (SA), an alert that populated non-antibiotic treatment options if an inappropriate antibiotic was prescribed; Accountable Justifications (JA), which prompted the prescriber to enter a justification for an inappropriately prescribed antibiotic that would then be documented in the patient's chart; and Peer Comparison (PC), an email periodically sent to each prescriber comparing his/her antibiotic prescribing rate with those who had the lowest rates of inappropriate antibiotic prescribing. A DCE study component was administered to determine whether prescribers felt SA, JA, PC, pay-for-performance or additional clinic time would most effectively reduce their inappropriate antibiotic prescribing. Willingness-to-pay (WTP) was calculated for each intervention. Results In the RCT, PC and JA were found to be the most effective interventions to reduce inappropriate antibiotic prescribing, whereas SA was not significantly different from controls. In the DCE however, regardless of treatment intervention received during the RCT, prescribers overwhelmingly preferred SA, followed by PC, then JA. WTP estimates indicated that each intervention would be significantly cheaper to implement than pay-for-performance incentives of $200/month

  19. The effects of convenience and quality on the demand for vaccination: Results from a discrete choice experiment.

    PubMed

    Guo, Na; Zhang, Guojie; Zhu, Dawei; Wang, Jian; Shi, Luwen

    2017-05-15

    Vaccination is an effective way to prevent infectious diseases. Most studies analysed people's vaccine decisions, but few studies have analysed the effects of convenience such as immunisation schedule and distance and the quality of vaccination service on vaccination uptake. The aim of this paper was to investigate adults' preferences for convenience and quality of vaccination service, calculate the private economic benefit from convenience (vaccination schedule and distance) and quality, and predict the uptake rate for different vaccine scenarios. In our study, we interviewed 266 adults in 2 counties of Shandong province in China. The discrete choice experiment (DCE) was employed to analyse the preference for hepatitis B virus (HBV) vaccination, and a mixed logit model was used to estimate respondent preferences for vaccination attributes included in the DCE. The protection rate against hepatitis B (HB), duration of protection, risk of side effects, vaccination cost, schedule, and vaccination sites were proved to influence adults' preferences for HBV vaccination. The estimated willingness to pay (WTP) for 1 dose schedule instead of 3 doses and for a third-level vaccination site instead of a first-level site was almost equal (19 RMB). However, if the protection duration of the vaccination programme changed from 5years to 20years, the adults were willing to pay 35.05 RMB, and WTP for a 99% protection rate instead of a 79% rate was 67.71 RMB. The predicted uptake rate is almost 43% for the base case of HBV vaccination. Adults made trade-offs between vaccination schedules, vaccination sites, and other characteristics of HBV vaccine. The impact of attributes of the vaccine itself, especially protection rate against HB, duration of protection, and risk of side-effects, is more dramatic than convenience and quality of vaccination service. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  20. Patient and nurse preferences for nurse handover-using preferences to inform policy: a discrete choice experiment protocol.

    PubMed

    Spinks, Jean; Chaboyer, Wendy; Bucknall, Tracey; Tobiano, Georgia; Whitty, Jennifer A

    2015-11-11

    Nursing bedside handover in hospital has been identified as an opportunity to involve patients and promote patient-centred care. It is important to consider the preferences of both patients and nurses when implementing bedside handover to maximise the successful uptake of this policy. We outline a study which aims to (1) identify, compare and contrast the preferences for various aspects of handover common to nurses and patients while accounting for other factors, such as the time constraints of nurses that may influence these preferences.; (2) identify opportunities for nurses to better involve patients in bedside handover and (3) identify patient and nurse preferences that may challenge the full implementation of bedside handover in the acute medical setting. We outline the protocol for a discrete choice experiment (DCE) which uses a survey design common to both patients and nurses. We describe the qualitative and pilot work undertaken to design the DCE. We use a D-efficient design which is informed by prior coefficients collected during the pilot phase. We also discuss the face-to-face administration of this survey in a population of acutely unwell, hospitalised patients and describe how data collection challenges have been informed by our pilot phase. Mixed multinomial logit regression analysis will be used to estimate the final results. This study has been approved by a university ethics committee as well as two participating hospital ethics committees. Results will be used within a knowledge translation framework to inform any strategies that can be used by nursing staff to improve the uptake of bedside handover. Results will also be disseminated via peer-reviewed journal articles and will be presented at national and international conferences. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  1. Effects of financial incentives on motivating physical activity among older adults: results from a discrete choice experiment.

    PubMed

    Farooqui, Muhammad Assad; Tan, Yock-Theng; Bilger, Marcel; Finkelstein, Eric A

    2014-02-10

    There is extensive evidence that regular physical activity confers numerous health benefits. Despite this, high rates of physical inactivity prevail among older adults. This study aimed to ascertain if incentives could be effective in motivating physical activity through improving uptake of walking programs, either with or without an enrolment fee to cover corresponding costs. A discrete-choice conjoint survey was fielded to a national sample of older adults in Singapore. Each respondent was given ten pairs of hypothetical walking programs and asked to choose the option they preferred. Each option varied along several dimensions, including the level and type (cash, voucher, or health savings credit) of incentive and an enrolment fee. For each option, they were asked how likely they would be to join their preferred program. A random utility model (RUM) was used to analyze the responses. Results suggest that a free 6-month program with a $500 cash incentive would generate enrolment rates of 58.5%; charging $50 to enroll lowers this to 55.7%. In terms of incentive type, cash payments were the most preferred incentive but not significantly different from supermarket vouchers. Both were preferred to health savings credits and sporting goods vouchers. Concerns of adverse selection were minimal because those who were inactive represented at least 72% of new participants for any offered program(s) and were the majority. Study results demonstrate the potential for even modest incentives to increase program uptake among inactive older adults. Moreover, although cash was the most preferred option, supermarket vouchers, which could potentially be purchased at a discount, were a close alternative. Results also suggest that an enrolment fee is a viable option to offset the costs of incentives as it has only minimal impact on participation.

  2. Stated Preferences of Doctors for Choosing a Job in Rural Areas of Peru: A Discrete Choice Experiment

    PubMed Central

    Miranda, J. Jaime; Diez-Canseco, Francisco; Lema, Claudia; Lescano, Andrés G.; Lagarde, Mylene; Blaauw, Duane; Huicho, Luis

    2012-01-01

    Background Doctors’ scarcity in rural areas remains a serious problem in Latin America and Peru. Few studies have explored job preferences of doctors working in underserved areas. We aimed to investigate doctors’ stated preferences for rural jobs. Methods and Findings A labelled discrete choice experiment (DCE) was performed in Ayacucho, an underserved department of Peru. Preferences were assessed for three locations: rural community, Ayacucho city (Ayacucho’s capital) and other provincial capital city. Policy simulations were run to assess the effect of job attributes on uptake of a rural post. Multiple conditional logistic regressions were used to assess the relative importance of job attributes and of individual characteristics. A total of 102 doctors participated. They were five times more likely to choose a job post in Ayacucho city over a rural community (OR 4.97, 95%CI 1.2; 20.54). Salary increases and bonus points for specialization acted as incentives to choose a rural area, while increase in the number of years needed to get a permanent post acted as a disincentive. Being male and working in a hospital reduced considerably chances of choosing a rural job, while not living with a partner increased them. Policy simulations showed that a package of 75% salary increase, getting a permanent contract after two years in rural settings, and getting bonus points for further specialisation increased rural job uptake from 21% to 77%. A package of 50% salary increase plus bonus points for further specialisation would also increase the rural uptake from 21% to 52%. Conclusions Doctors are five times more likely to favour a job in urban areas over rural settings. This strong preference needs to be overcome by future policies aimed at improving the scarcity of rural doctors. Some incentives, alone or combined, seem feasible and sustainable, whilst others may pose a high fiscal burden. PMID:23272065

  3. Patient and nurse preferences for nurse handover—using preferences to inform policy: a discrete choice experiment protocol

    PubMed Central

    Spinks, Jean; Chaboyer, Wendy; Bucknall, Tracey; Tobiano, Georgia; Whitty, Jennifer A

    2015-01-01

    Introduction Nursing bedside handover in hospital has been identified as an opportunity to involve patients and promote patient-centred care. It is important to consider the preferences of both patients and nurses when implementing bedside handover to maximise the successful uptake of this policy. We outline a study which aims to (1) identify, compare and contrast the preferences for various aspects of handover common to nurses and patients while accounting for other factors, such as the time constraints of nurses that may influence these preferences.; (2) identify opportunities for nurses to better involve patients in bedside handover and (3) identify patient and nurse preferences that may challenge the full implementation of bedside handover in the acute medical setting. Methods and analysis We outline the protocol for a discrete choice experiment (DCE) which uses a survey design common to both patients and nurses. We describe the qualitative and pilot work undertaken to design the DCE. We use a D-efficient design which is informed by prior coefficients collected during the pilot phase. We also discuss the face-to-face administration of this survey in a population of acutely unwell, hospitalised patients and describe how data collection challenges have been informed by our pilot phase. Mixed multinomial logit regression analysis will be used to estimate the final results. Ethics and dissemination This study has been approved by a university ethics committee as well as two participating hospital ethics committees. Results will be used within a knowledge translation framework to inform any strategies that can be used by nursing staff to improve the uptake of bedside handover. Results will also be disseminated via peer-reviewed journal articles and will be presented at national and international conferences. PMID:26560060

  4. Phase retrieval with the transport-of-intensity equation in an arbitrarily-shaped aperture by iterative discrete cosine transforms

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Huang, Lei; Zuo, Chao; Idir, Mourad

    A novel transport-of-intensity equation (TIE) based phase retrieval method is proposed with putting an arbitrarily-shaped aperture into the optical wavefield. In this arbitrarily-shaped aperture, the TIE can be solved under non-uniform illuminations and even non-homogeneous boundary conditions by iterative discrete cosine transforms with a phase compensation mechanism. Simulation with arbitrary phase, arbitrary aperture shape, and non-uniform intensity distribution verifies the effective compensation and high accuracy of the proposed method. Experiment is also carried out to check the feasibility of the proposed method in real measurement. Comparing to the existing methods, the proposed method is applicable for any types of phasemore » distribution under non-uniform illumination and non-homogeneous boundary conditions within an arbitrarily-shaped aperture, which enables the technique of TIE with hard aperture become a more flexible phase retrieval tool in practical measurements.« less

  5. Phase retrieval with the transport-of-intensity equation in an arbitrarily-shaped aperture by iterative discrete cosine transforms

    DOE PAGES

    Huang, Lei; Zuo, Chao; Idir, Mourad; ...

    2015-04-21

    A novel transport-of-intensity equation (TIE) based phase retrieval method is proposed with putting an arbitrarily-shaped aperture into the optical wavefield. In this arbitrarily-shaped aperture, the TIE can be solved under non-uniform illuminations and even non-homogeneous boundary conditions by iterative discrete cosine transforms with a phase compensation mechanism. Simulation with arbitrary phase, arbitrary aperture shape, and non-uniform intensity distribution verifies the effective compensation and high accuracy of the proposed method. Experiment is also carried out to check the feasibility of the proposed method in real measurement. Comparing to the existing methods, the proposed method is applicable for any types of phasemore » distribution under non-uniform illumination and non-homogeneous boundary conditions within an arbitrarily-shaped aperture, which enables the technique of TIE with hard aperture become a more flexible phase retrieval tool in practical measurements.« less

  6. Box-Cox Mixed Logit Model for Travel Behavior Analysis

    NASA Astrophysics Data System (ADS)

    Orro, Alfonso; Novales, Margarita; Benitez, Francisco G.

    2010-09-01

    To represent the behavior of travelers when they are deciding how they are going to get to their destination, discrete choice models, based on the random utility theory, have become one of the most widely used tools. The field in which these models were developed was halfway between econometrics and transport engineering, although the latter now constitutes one of their principal areas of application. In the transport field, they have mainly been applied to mode choice, but also to the selection of destination, route, and other important decisions such as the vehicle ownership. In usual practice, the most frequently employed discrete choice models implement a fixed coefficient utility function that is linear in the parameters. The principal aim of this paper is to present the viability of specifying utility functions with random coefficients that are nonlinear in the parameters, in applications of discrete choice models to transport. Nonlinear specifications in the parameters were present in discrete choice theory at its outset, although they have seldom been used in practice until recently. The specification of random coefficients, however, began with the probit and the hedonic models in the 1970s, and, after a period of apparent little practical interest, has burgeoned into a field of intense activity in recent years with the new generation of mixed logit models. In this communication, we present a Box-Cox mixed logit model, original of the authors. It includes the estimation of the Box-Cox exponents in addition to the parameters of the random coefficients distribution. Probability of choose an alternative is an integral that will be calculated by simulation. The estimation of the model is carried out by maximizing the simulated log-likelihood of a sample of observed individual choices between alternatives. The differences between the predictions yielded by models that are inconsistent with real behavior have been studied with simulation experiments.

  7. The effects of physical activity on impulsive choice: Influence of sensitivity to reinforcement amount and delay

    PubMed Central

    Strickland, Justin C.; Feinstein, Max A.; Lacy, Ryan T.; Smith, Mark A.

    2016-01-01

    Impulsive choice is a diagnostic feature and/or complicating factor for several psychological disorders and may be examined in the laboratory using delay-discounting procedures. Recent investigators have proposed using quantitative measures of analysis to examine the behavioral processes contributing to impulsive choice. The purpose of this study was to examine the effects of physical activity (i.e., wheel running) on impulsive choice in a single-response, discrete-trial procedure using two quantitative methods of analysis. To this end, rats were assigned to physical activity or sedentary groups and trained to respond in a delay-discounting procedure. In this procedure, one lever always produced one food pellet immediately, whereas a second lever produced three food pellets after a 0, 10, 20, 40, or 80-second delay. Estimates of sensitivity to reinforcement amount and sensitivity to reinforcement delay were determined using (1) a simple linear analysis and (2) an analysis of logarithmically transformed response ratios. Both analyses revealed that physical activity decreased sensitivity to reinforcement amount and sensitivity to reinforcement delay. These findings indicate that (1) physical activity has significant but functionally opposing effects on the behavioral processes that contribute to impulsive choice and (2) both quantitative methods of analysis are appropriate for use in single-response, discrete-trial procedures. PMID:26964905

  8. Principles of Discrete Time Mechanics

    NASA Astrophysics Data System (ADS)

    Jaroszkiewicz, George

    2014-04-01

    1. Introduction; 2. The physics of discreteness; 3. The road to calculus; 4. Temporal discretization; 5. Discrete time dynamics architecture; 6. Some models; 7. Classical cellular automata; 8. The action sum; 9. Worked examples; 10. Lee's approach to discrete time mechanics; 11. Elliptic billiards; 12. The construction of system functions; 13. The classical discrete time oscillator; 14. Type 2 temporal discretization; 15. Intermission; 16. Discrete time quantum mechanics; 17. The quantized discrete time oscillator; 18. Path integrals; 19. Quantum encoding; 20. Discrete time classical field equations; 21. The discrete time Schrodinger equation; 22. The discrete time Klein-Gordon equation; 23. The discrete time Dirac equation; 24. Discrete time Maxwell's equations; 25. The discrete time Skyrme model; 26. Discrete time quantum field theory; 27. Interacting discrete time scalar fields; 28. Space, time and gravitation; 29. Causality and observation; 30. Concluding remarks; Appendix A. Coherent states; Appendix B. The time-dependent oscillator; Appendix C. Quaternions; Appendix D. Quantum registers; References; Index.

  9. An Empirical Investigation of Occupational Choice and Human Capital Accumulation at Mid-Life

    ERIC Educational Resources Information Center

    Xue, Yu

    2010-01-01

    Individual variation in labor supply can arise from more than just a choice among discrete occupation groups, especially given the joint process of wage determination and time allocation. Other factors can include differential preferences for earnings, the time length of work and other related occupational attributes. Using data from the Wisconsin…

  10. Improving the public health sector in South Africa: eliciting public preferences using a discrete choice experiment.

    PubMed

    Honda, Ayako; Ryan, Mandy; van Niekerk, Robert; McIntyre, Diane

    2015-06-01

    The introduction of national health insurance (NHI), aimed at achieving universal coverage, is the most important issue currently on the South African health policy agenda. Improvement in public sector health-care provision is crucial for the successful implementation of NHI as, regardless of whether health-care services become more affordable and available, if the quality of the services provided is not acceptable, people will not use the services. Although there has been criticism of the quality of public sector health services, limited research is available to identify what communities regard as the greatest problems with the services. A discrete choice experiment (DCE) was undertaken to elicit public preferences on key dimensions of quality of care when selecting public health facilities in South Africa. Qualitative methods were applied to establish attributes and levels for the DCE. To elicit preferences, interviews with community members were held in two South African provinces: 491 in Western Cape and 499 in Eastern Cape. The availability of necessary medicine at health facilities has the greatest impact on the probability of attending public health facilities. Other clinical quality attributes (i.e. provision of expert advice and provision of a thorough examination) are more valued than non-clinical quality of care attributes (i.e. staff attitude, treatment by doctors or nurses, and waiting time). Treatment by a doctor was less valued than all other attributes. Communities are prepared to tolerate public sector health service characteristics such as a long waiting time, poor staff attitudes and lack of direct access to doctors if they receive the medicine they need, a thorough examination and a clear explanation of the diagnosis and prescribed treatment from health professionals. These findings prioritize issues that the South African government must address in order to meet their commitment to improve public sector health-care service provision. Published

  11. Type 2 diabetes patients’ preferences and willingness to pay for lifestyle programs: a discrete choice experiment

    PubMed Central

    2013-01-01

    Background Participation rates of lifestyle programs among type 2 diabetes mellitus (T2DM) patients are less than optimal around the globe. Whereas research shows notable delays in the development of the disease among lifestyle program participants. Very little is known about the relative importance of barriers for participation as well as the willingness of T2DM patients to pay for participation in such programs. The aim of this study was to identify the preferences of T2DM patients with regard to lifestyle programs and to calculate participants’ willingness to pay (WTP) as well as to estimate the potential participation rates of lifestyle programs. Methods A Discrete Choice Experiment (DCE) questionnaire assessing five different lifestyle program attributes was distributed among 1250 Dutch adults aged 35–65 years with T2DM, 391 questionnaires (31%) were returned and included in the analysis. The relative importance of the program attributes (i.e., meal plan, physical activity (PA) schedule, consultation structure, expected program outcome and out-of-pocket costs) was determined using panel-mixed logit models. Based on the retrieved attribute estimates, patients’ WTP and potential participation rates were determined. Results The out-of-pocket costs (β = −0.75, P < .001), consultation structure (β = −0.46, P < .001) and expected outcome (β = 0.72, P < .001) were the most important factors for respondents when deciding whether to participate in a lifestyle program. Respondents were willing to pay €128 per year for individual instead of group consultation and €97 per year for 10 kilograms anticipated weight loss. Potential participation rates for different lifestyle-program scenarios ranged between 48.5% and 62.4%. Conclusions When deciding whether to participate in a lifestyle program, T2DM patients are mostly driven by low levels of out-of-pocket costs. Thereafter, they prefer individual consultation and high levels of anticipated

  12. Patient and Oncology Nurse Preferences for the Treatment Options in Advanced Melanoma: A Discrete Choice Experiment.

    PubMed

    Liu, Frank Xiaoqing; Witt, Edward A; Ebbinghaus, Scot; DiBonaventura Beyer, Grace; Basurto, Enrique; Joseph, Richard W

    2017-10-25

    Understanding the perceptions of patients and oncology nurses about the relative importance of benefits and risks associated with newer treatments of advanced melanoma can help to inform clinical decision-making. The aims of this study were to quantify and compare the views of patients and oncology nurses regarding the importance of attributes of treatments of advanced melanoma. A discrete choice experiment (DCE) was conducted in US-based oncology nurses and patients diagnosed with advanced melanoma. Patients and nurses were enlisted through online panels. In a series of scenarios, respondents had to choose between 2 hypothetical treatments, each with 7 attributes: mode of administration (MoA), dosing schedule (DS), median duration of therapy (DoT), objective response rate (ORR), progression-free survival (PFS), overall survival (OS), and grade 3 or 4 adverse events (AEs). Hierarchical Bayesian logistic regression models were used to estimate preference weights. A total of 200 patients with advanced melanoma and 150 oncology nurses participated. The relative importance estimates of attributes by patients and nurses, respectively, were as follows: OS, 33% and 28%; AEs, 29% and 26%; ORR, 25% and 27%; PFS, 12% and 15%; DS, 2% and 3%; DoT, 0% and 0%; and MoA, 0% and 0%. Both patients and oncology nurses valued OS, ORR, and AEs as the most important treatment attributes for advanced melanoma, followed by PFS, whereas DS, DoT, and MoA were given less value in their treatment decisions. Oncology nurses and patients have similar views on important treatment considerations for advanced melanoma, which can help build trust in shared decision-making.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.

  13. A scalable block-preconditioning strategy for divergence-conforming B-spline discretizations of the Stokes problem

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cortes, Adriano M.; Dalcin, Lisandro; Sarmiento, Adel F.

    The recently introduced divergence-conforming B-spline discretizations allow the construction of smooth discrete velocity–pressure pairs for viscous incompressible flows that are at the same time inf–sup stable and pointwise divergence-free. When applied to the discretized Stokes problem, these spaces generate a symmetric and indefinite saddle-point linear system. The iterative method of choice to solve such system is the Generalized Minimum Residual Method. This method lacks robustness, and one remedy is to use preconditioners. For linear systems of saddle-point type, a large family of preconditioners can be obtained by using a block factorization of the system. In this paper, we show howmore » the nesting of “black-box” solvers and preconditioners can be put together in a block triangular strategy to build a scalable block preconditioner for the Stokes system discretized by divergence-conforming B-splines. Lastly, besides the known cavity flow problem, we used for benchmark flows defined on complex geometries: an eccentric annulus and hollow torus of an eccentric annular cross-section.« less

  14. A scalable block-preconditioning strategy for divergence-conforming B-spline discretizations of the Stokes problem

    DOE PAGES

    Cortes, Adriano M.; Dalcin, Lisandro; Sarmiento, Adel F.; ...

    2016-10-19

    The recently introduced divergence-conforming B-spline discretizations allow the construction of smooth discrete velocity–pressure pairs for viscous incompressible flows that are at the same time inf–sup stable and pointwise divergence-free. When applied to the discretized Stokes problem, these spaces generate a symmetric and indefinite saddle-point linear system. The iterative method of choice to solve such system is the Generalized Minimum Residual Method. This method lacks robustness, and one remedy is to use preconditioners. For linear systems of saddle-point type, a large family of preconditioners can be obtained by using a block factorization of the system. In this paper, we show howmore » the nesting of “black-box” solvers and preconditioners can be put together in a block triangular strategy to build a scalable block preconditioner for the Stokes system discretized by divergence-conforming B-splines. Lastly, besides the known cavity flow problem, we used for benchmark flows defined on complex geometries: an eccentric annulus and hollow torus of an eccentric annular cross-section.« less

  15. Farmers' valuation of incentives to produce genetically modified organism-free milk: Insights from a discrete choice experiment in Germany.

    PubMed

    Schreiner, J A; Latacz-Lohmann, U

    2015-11-01

    This paper investigates farmers' willingness to participate in a genetically modified organism (GMO)-free milk production scheme offered by some German dairy companies. The empirical analysis is based upon discrete choice experiments with 151 dairy farmers from 2 regions in Germany. A conditional logit estimation reveals a strong positive effect of the price premium on offer. Reliable feed monitoring and free technical support increase the likelihood of scheme adoption, the latter however only in farms that have been receiving technical support in other fields. By contrast, any interference with the entrepreneurial autonomy of farmers, through pre-arranged feed procurement or prescriptive advice on the part of the dairy company, lowers acceptance probabilities. Farmers' attitudes toward cultivation of genetically modified soy, their assessment of the market potential of GMO-free milk and future feed prices were found to be significant determinants of adoption, as are farmer age, educational status, and current feeding regimens. Respondents requested on average a mark-up of 0.80 eurocents per kilogram of milk to accept a contract. Comparison of the estimates for the 2 regions suggests that farmers in northern Germany are, on average, more likely to convert to genetically modified-free production; however, farmers in the south are, ceteris paribus, more responsive to an increase in the price premium offered. A latent class model reveals significant differences in the valuation of scheme attributes between 2 latent classes of adopters and nonadopters. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  16. Eliciting preferences for priority setting in genetic testing: a pilot study comparing best-worst scaling and discrete-choice experiments.

    PubMed

    Severin, Franziska; Schmidtke, Jörg; Mühlbacher, Axel; Rogowski, Wolf H

    2013-11-01

    Given the increasing number of genetic tests available, decisions have to be made on how to allocate limited health-care resources to them. Different criteria have been proposed to guide priority setting. However, their relative importance is unclear. Discrete-choice experiments (DCEs) and best-worst scaling experiments (BWSs) are methods used to identify and weight various criteria that influence orders of priority. This study tests whether these preference eliciting techniques can be used for prioritising genetic tests and compares the empirical findings resulting from these two approaches. Pilot DCE and BWS questionnaires were developed for the same criteria: prevalence, severity, clinical utility, alternatives to genetic testing available, infrastructure for testing and care established, and urgency of care. Interview-style experiments were carried out among different genetics professionals (mainly clinical geneticists, researchers and biologists). A total of 31 respondents completed the DCE and 26 completed the BWS experiment. Weights for the levels of the six attributes were estimated by conditional logit models. Although the results derived from the DCE and BWS experiments differed in detail, we found similar valuation patterns in the DCE and BWS experiments. The respondents attached greatest value to tests with high clinical utility (defined by the availability of treatments that reduce mortality and morbidity) and to testing for highly prevalent conditions. The findings from this study exemplify how decision makers can use quantitative preference eliciting methods to measure aggregated preferences in order to prioritise alternative clinical interventions. Further research is necessary to confirm the survey results.

  17. Constructing experimental designs for discrete-choice experiments: report of the ISPOR Conjoint Analysis Experimental Design Good Research Practices Task Force.

    PubMed

    Reed Johnson, F; Lancsar, Emily; Marshall, Deborah; Kilambi, Vikram; Mühlbacher, Axel; Regier, Dean A; Bresnahan, Brian W; Kanninen, Barbara; Bridges, John F P

    2013-01-01

    Stated-preference methods are a class of evaluation techniques for studying the preferences of patients and other stakeholders. While these methods span a variety of techniques, conjoint-analysis methods-and particularly discrete-choice experiments (DCEs)-have become the most frequently applied approach in health care in recent years. Experimental design is an important stage in the development of such methods, but establishing a consensus on standards is hampered by lack of understanding of available techniques and software. This report builds on the previous ISPOR Conjoint Analysis Task Force Report: Conjoint Analysis Applications in Health-A Checklist: A Report of the ISPOR Good Research Practices for Conjoint Analysis Task Force. This report aims to assist researchers specifically in evaluating alternative approaches to experimental design, a difficult and important element of successful DCEs. While this report does not endorse any specific approach, it does provide a guide for choosing an approach that is appropriate for a particular study. In particular, it provides an overview of the role of experimental designs for the successful implementation of the DCE approach in health care studies, and it provides researchers with an introduction to constructing experimental designs on the basis of study objectives and the statistical model researchers have selected for the study. The report outlines the theoretical requirements for designs that identify choice-model preference parameters and summarizes and compares a number of available approaches for constructing experimental designs. The task-force leadership group met via bimonthly teleconferences and in person at ISPOR meetings in the United States and Europe. An international group of experimental-design experts was consulted during this process to discuss existing approaches for experimental design and to review the task force's draft reports. In addition, ISPOR members contributed to developing a consensus

  18. Multiple-Choice versus Constructed-Response Tests in the Assessment of Mathematics Computation Skills.

    ERIC Educational Resources Information Center

    Gadalla, Tahany M.

    The equivalence of multiple-choice (MC) and constructed response (discrete) (CR-D) response formats as applied to mathematics computation at grade levels two to six was tested. The difference between total scores from the two response formats was tested for statistical significance, and the factor structure of items in both response formats was…

  19. Educational Choice: Practical Policy Questions. Occasional Paper Series No. 7.

    ERIC Educational Resources Information Center

    First, Patricia F.

    The consideration of school choice plans raises policy questions for school administrators. This paper addresses pragmatic concerns about definitions and policy questions related to educational finance. Interdistrict choice, emphasizing families' right to choose among existing public schools, raises questions regarding transportation and…

  20. Proportional exponentiated link transformed hazards (ELTH) models for discrete time survival data with application

    PubMed Central

    Joeng, Hee-Koung; Chen, Ming-Hui; Kang, Sangwook

    2015-01-01

    Discrete survival data are routinely encountered in many fields of study including behavior science, economics, epidemiology, medicine, and social science. In this paper, we develop a class of proportional exponentiated link transformed hazards (ELTH) models. We carry out a detailed examination of the role of links in fitting discrete survival data and estimating regression coefficients. Several interesting results are established regarding the choice of links and baseline hazards. We also characterize the conditions for improper survival functions and the conditions for existence of the maximum likelihood estimates under the proposed ELTH models. An extensive simulation study is conducted to examine the empirical performance of the parameter estimates under the Cox proportional hazards model by treating discrete survival times as continuous survival times, and the model comparison criteria, AIC and BIC, in determining links and baseline hazards. A SEER breast cancer dataset is analyzed in details to further demonstrate the proposed methodology. PMID:25772374

  1. Cognitive overload? An exploration of the potential impact of cognitive functioning in discrete choice experiments with older people in health care.

    PubMed

    Milte, Rachel; Ratcliffe, Julie; Chen, Gang; Lancsar, Emily; Miller, Michelle; Crotty, Maria

    2014-07-01

    This exploratory study sought to investigate the effect of cognitive functioning on the consistency of individual responses to a discrete choice experiment (DCE) study conducted exclusively with older people. A DCE to investigate preferences for multidisciplinary rehabilitation was administered to a consenting sample of older patients (aged 65 years and older) after surgery to repair a fractured hip (N = 84). Conditional logit, mixed logit, heteroscedastic conditional logit, and generalized multinomial logit regression models were used to analyze the DCE data and to explore the relationship between the level of cognitive functioning (specifically the absence or presence of mild cognitive impairment as assessed by the Mini-Mental State Examination) and preference and scale heterogeneity. Both the heteroscedastic conditional logit and generalized multinomial logit models indicated that the presence of mild cognitive impairment did not have a significant effect on the consistency of responses to the DCE. This study provides important preliminary evidence relating to the effect of mild cognitive impairment on DCE responses for older people. It is important that further research be conducted in larger samples and more diverse populations to further substantiate the findings from this exploratory study and to assess the practicality and validity of the DCE approach with populations of older people. Copyright © 2014 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  2. Multilayer shallow water models with locally variable number of layers and semi-implicit time discretization

    NASA Astrophysics Data System (ADS)

    Bonaventura, Luca; Fernández-Nieto, Enrique D.; Garres-Díaz, José; Narbona-Reina, Gladys

    2018-07-01

    We propose an extension of the discretization approaches for multilayer shallow water models, aimed at making them more flexible and efficient for realistic applications to coastal flows. A novel discretization approach is proposed, in which the number of vertical layers and their distribution are allowed to change in different regions of the computational domain. Furthermore, semi-implicit schemes are employed for the time discretization, leading to a significant efficiency improvement for subcritical regimes. We show that, in the typical regimes in which the application of multilayer shallow water models is justified, the resulting discretization does not introduce any major spurious feature and allows again to reduce substantially the computational cost in areas with complex bathymetry. As an example of the potential of the proposed technique, an application to a sediment transport problem is presented, showing a remarkable improvement with respect to standard discretization approaches.

  3. Location choices for climate change and transportation decision making.

    DOT National Transportation Integrated Search

    2015-01-01

    This research aims to fill the gap in the knowledge between residential location decisions and : preferences and the resulting travel outcomes. In this first phase, the revealed connections between : residential choices and travel patterns are examin...

  4. Fiber-dependent deautonomization of integrable 2D mappings and discrete Painlevé equations

    NASA Astrophysics Data System (ADS)

    Carstea, Adrian Stefan; Dzhamay, Anton; Takenawa, Tomoyuki

    2017-10-01

    It is well known that two-dimensional mappings preserving a rational elliptic fibration, like the Quispel-Roberts-Thompson mappings, can be deautonomized to discrete Painlevé equations. However, the dependence of this procedure on the choice of a particular elliptic fiber has not been sufficiently investigated. In this paper we establish a way of performing the deautonomization for a pair of an autonomous mapping and a fiber. Starting from a single autonomous mapping but varying the type of a chosen fiber, we obtain different types of discrete Painlevé equations using this deautonomization procedure. We also introduce a technique for reconstructing a mapping from the knowledge of its induced action on the Picard group and some additional geometric data. This technique allows us to obtain factorized expressions of discrete Painlevé equations, including the elliptic case. Further, by imposing certain restrictions on such non-autonomous mappings we obtain new and simple elliptic difference Painlevé equations, including examples whose symmetry groups do not appear explicitly in Sakai’s classification.

  5. Walk Score, Transportation Mode Choice, and Walking Among French Adults: A GPS, Accelerometer, and Mobility Survey Study.

    PubMed

    Duncan, Dustin T; Méline, Julie; Kestens, Yan; Day, Kristen; Elbel, Brian; Trasande, Leonardo; Chaix, Basile

    2016-06-20

    Few studies have used GPS data to analyze the relationship between Walk Score, transportation choice and walking. Additionally, the influence of Walk Score is understudied using trips rather than individuals as statistical units. The purpose of this study is to examine associations at the trip level between Walk Score, transportation mode choice, and walking among Paris adults who were tracked with GPS receivers and accelerometers in the RECORD GPS Study. In the RECORD GPS Study, 227 participants were tracked during seven days with GPS receivers and accelerometers. Participants were also surveyed with a GPS-based web mapping application on their activities and transportation modes for all trips (6969 trips). Walk Score, which calculates neighborhood walkability, was assessed for each origin and destination of every trip. Multilevel logistic and linear regression analyses were conducted to estimate associations between Walk Score and walking in the trip or accelerometry-assessed number of steps for each trip, after adjustment for individual/neighborhood characteristics. The mean overall Walk Scores for trip origins were 87.1 (SD = 14.4) and for trip destinations 87.1 (SD = 14.5). In adjusted trip-level associations between Walk Score and walking only in the trip, we found that a walkable neighborhood in the trip origin and trip destination was associated with increased odds of walking in the trip assessed in the survey. The odds of only walking in the trip were 3.48 (95% CI: 2.73 to 4.44) times higher when the Walk Score for the trip origin was "Walker's Paradise" compared to less walkable neighborhoods (Very/Car-Dependent or Somewhat Walkable), with an identical independent effect of trip destination Walk Score on walking. The number of steps per 10 min (as assessed with accelerometry) was cumulatively higher for trips both originating and ending in walkable neighborhoods (i.e., "Very Walkable"). Walkable neighborhoods were associated with increases in walking

  6. Walk Score, Transportation Mode Choice, and Walking Among French Adults: A GPS, Accelerometer, and Mobility Survey Study

    PubMed Central

    Duncan, Dustin T.; Méline, Julie; Kestens, Yan; Day, Kristen; Elbel, Brian; Trasande, Leonardo; Chaix, Basile

    2016-01-01

    Background: Few studies have used GPS data to analyze the relationship between Walk Score, transportation choice and walking. Additionally, the influence of Walk Score is understudied using trips rather than individuals as statistical units. The purpose of this study is to examine associations at the trip level between Walk Score, transportation mode choice, and walking among Paris adults who were tracked with GPS receivers and accelerometers in the RECORD GPS Study. Methods: In the RECORD GPS Study, 227 participants were tracked during seven days with GPS receivers and accelerometers. Participants were also surveyed with a GPS-based web mapping application on their activities and transportation modes for all trips (6969 trips). Walk Score, which calculates neighborhood walkability, was assessed for each origin and destination of every trip. Multilevel logistic and linear regression analyses were conducted to estimate associations between Walk Score and walking in the trip or accelerometry-assessed number of steps for each trip, after adjustment for individual/neighborhood characteristics. Results: The mean overall Walk Scores for trip origins were 87.1 (SD = 14.4) and for trip destinations 87.1 (SD = 14.5). In adjusted trip-level associations between Walk Score and walking only in the trip, we found that a walkable neighborhood in the trip origin and trip destination was associated with increased odds of walking in the trip assessed in the survey. The odds of only walking in the trip were 3.48 (95% CI: 2.73 to 4.44) times higher when the Walk Score for the trip origin was “Walker’s Paradise” compared to less walkable neighborhoods (Very/Car-Dependent or Somewhat Walkable), with an identical independent effect of trip destination Walk Score on walking. The number of steps per 10 min (as assessed with accelerometry) was cumulatively higher for trips both originating and ending in walkable neighborhoods (i.e., “Very Walkable”). Conclusions: Walkable

  7. How do women trade-off benefits and risks in chemotherapy treatment decisions based on gene expression profiling for early-stage breast cancer? A discrete choice experiment.

    PubMed

    Marshall, Deborah A; Deal, Ken; Bombard, Yvonne; Leighl, Natasha; MacDonald, Karen V; Trudeau, Maureen

    2016-06-02

    Gene expression profiling (GEP) of tumours informs baseline risk prediction, potentially affecting adjuvant chemotherapy decisions for women with early-stage breast cancer. Since only 15% will experience a recurrence, concerns have been raised about potential harms from overtreatment and high GEP costs in publicly funded healthcare systems. We aimed to estimate preferences and personal utility of GEP testing information and benefit-risk trade-offs in chemotherapy treatment decisions. Based on literature review and findings from our qualitative research (focus groups, interviews with patients with breast cancer and medical oncologists), we developed a discrete choice experiment (DCE) survey and administered it via an internet panel. The DCE included 12 choice tasks with 5 attributes and 3 alternatives considering orthogonality, D-efficiency and level balance. The DCE survey was administered to 1004 Canadian women from the general population. Preferences were analysed using conditional logit and hierarchical Bayes and evaluated for goodness of fit. We conducted simulation analyses for alternative scenarios. GEP test score indicating likely benefit from chemotherapy was the most important attribute. Doctor's clinical estimate of the risk of cancer returning, trust in your cancer doctor and side effects of chemotherapy (temporary and permanent) were relatively less important but showed significant differences among levels. In the scenario analyses, 78% were likely to choose chemotherapy in a high-risk scenario, 55% in a moderate-risk scenario and 33% in a low-risk scenario, with the other attributes held constant. A high GEP score was more important in influencing the choice of chemotherapy for those at intermediate clinical risk. GEP testing information influences chemotherapy treatment decisions in early-stage breast cancer and varies depending on clinical risk. Clinicians should be aware of these differences and tailor the use of GEP testing accordingly. Published

  8. The effects of physical activity on impulsive choice: Influence of sensitivity to reinforcement amount and delay.

    PubMed

    Strickland, Justin C; Feinstein, Max A; Lacy, Ryan T; Smith, Mark A

    2016-05-01

    Impulsive choice is a diagnostic feature and/or complicating factor for several psychological disorders and may be examined in the laboratory using delay-discounting procedures. Recent investigators have proposed using quantitative measures of analysis to examine the behavioral processes contributing to impulsive choice. The purpose of this study was to examine the effects of physical activity (i.e., wheel running) on impulsive choice in a single-response, discrete-trial procedure using two quantitative methods of analysis. To this end, rats were assigned to physical activity or sedentary groups and trained to respond in a delay-discounting procedure. In this procedure, one lever always produced one food pellet immediately, whereas a second lever produced three food pellets after a 0, 10, 20, 40, or 80-s delay. Estimates of sensitivity to reinforcement amount and sensitivity to reinforcement delay were determined using (1) a simple linear analysis and (2) an analysis of logarithmically transformed response ratios. Both analyses revealed that physical activity decreased sensitivity to reinforcement amount and sensitivity to reinforcement delay. These findings indicate that (1) physical activity has significant but functionally opposing effects on the behavioral processes that contribute to impulsive choice and (2) both quantitative methods of analysis are appropriate for use in single-response, discrete-trial procedures. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Application of the discrete generalized multigroup method to ultra-fine energy mesh in infinite medium calculations

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gibson, N. A.; Forget, B.

    2012-07-01

    The Discrete Generalized Multigroup (DGM) method uses discrete Legendre orthogonal polynomials to expand the energy dependence of the multigroup neutron transport equation. This allows a solution on a fine energy mesh to be approximated for a cost comparable to a solution on a coarse energy mesh. The DGM method is applied to an ultra-fine energy mesh (14,767 groups) to avoid using self-shielding methodologies without introducing the cost usually associated with such energy discretization. Results show DGM to converge to the reference ultra-fine solution after a small number of recondensation steps for multiple infinite medium compositions. (authors)

  10. FUNGIBILITY AND CONSUMER CHOICE: EVIDENCE FROM COMMODITY PRICE SHOCKS.

    PubMed

    Hastings, Justine S; Shapiro, Jesse M

    2013-11-01

    We formulate a test of the fungibility of money based on parallel shifts in the prices of different quality grades of a commodity. We embed the test in a discrete-choice model of product quality choice and estimate the model using panel microdata on gasoline purchases. We find that when gasoline prices rise consumers substitute to lower octane gasoline, to an extent that cannot be explained by income effects. Across a wide range of specifications, we consistently reject the null hypothesis that households treat "gas money" as fungible with other income. We compare the empirical fit of three psychological models of decision-making. A simple model of category budgeting fits the data well, with models of loss aversion and salience both capturing important features of the time series.

  11. FUNGIBILITY AND CONSUMER CHOICE: EVIDENCE FROM COMMODITY PRICE SHOCKS*

    PubMed Central

    Hastings, Justine S.; Shapiro, Jesse M.

    2015-01-01

    We formulate a test of the fungibility of money based on parallel shifts in the prices of different quality grades of a commodity. We embed the test in a discrete-choice model of product quality choice and estimate the model using panel microdata on gasoline purchases. We find that when gasoline prices rise consumers substitute to lower octane gasoline, to an extent that cannot be explained by income effects. Across a wide range of specifications, we consistently reject the null hypothesis that households treat “gas money” as fungible with other income. We compare the empirical fit of three psychological models of decision-making. A simple model of category budgeting fits the data well, with models of loss aversion and salience both capturing important features of the time series. PMID:26937053

  12. Local and global dynamics of Ramsey model: From continuous to discrete time.

    PubMed

    Guzowska, Malgorzata; Michetti, Elisabetta

    2018-05-01

    The choice of time as a discrete or continuous variable may radically affect equilibrium stability in an endogenous growth model with durable consumption. In the continuous-time Ramsey model [F. P. Ramsey, Econ. J. 38(152), 543-559 (1928)], the steady state is locally saddle-path stable with monotonic convergence. However, in the discrete-time version, the steady state may be unstable or saddle-path stable with monotonic or oscillatory convergence or periodic solutions [see R.-A. Dana et al., Handbook on Optimal Growth 1 (Springer, 2006) and G. Sorger, Working Paper No. 1505 (2015)]. When this occurs, the discrete-time counterpart of the continuous-time model is not consistent with the initial framework. In order to obtain a discrete-time Ramsey model preserving the main properties of the continuous-time counterpart, we use a general backward and forward discretisation as initially proposed by Bosi and Ragot [Theor. Econ. Lett. 2(1), 10-15 (2012)]. The main result of the study here presented is that, with this hybrid discretisation method, fixed points and local dynamics do not change. For what it concerns global dynamics, i.e., long-run behavior for initial conditions taken on the state space, we mainly perform numerical analysis with the main scope of comparing both qualitative and quantitative evolution of the two systems, also varying some parameters of interest.

  13. Local and global dynamics of Ramsey model: From continuous to discrete time

    NASA Astrophysics Data System (ADS)

    Guzowska, Malgorzata; Michetti, Elisabetta

    2018-05-01

    The choice of time as a discrete or continuous variable may radically affect equilibrium stability in an endogenous growth model with durable consumption. In the continuous-time Ramsey model [F. P. Ramsey, Econ. J. 38(152), 543-559 (1928)], the steady state is locally saddle-path stable with monotonic convergence. However, in the discrete-time version, the steady state may be unstable or saddle-path stable with monotonic or oscillatory convergence or periodic solutions [see R.-A. Dana et al., Handbook on Optimal Growth 1 (Springer, 2006) and G. Sorger, Working Paper No. 1505 (2015)]. When this occurs, the discrete-time counterpart of the continuous-time model is not consistent with the initial framework. In order to obtain a discrete-time Ramsey model preserving the main properties of the continuous-time counterpart, we use a general backward and forward discretisation as initially proposed by Bosi and Ragot [Theor. Econ. Lett. 2(1), 10-15 (2012)]. The main result of the study here presented is that, with this hybrid discretisation method, fixed points and local dynamics do not change. For what it concerns global dynamics, i.e., long-run behavior for initial conditions taken on the state space, we mainly perform numerical analysis with the main scope of comparing both qualitative and quantitative evolution of the two systems, also varying some parameters of interest.

  14. Discrete Element Modelling of Floating Debris

    NASA Astrophysics Data System (ADS)

    Mahaffey, Samantha; Liang, Qiuhua; Parkin, Geoff; Large, Andy; Rouainia, Mohamed

    2016-04-01

    Flash flooding is characterised by high velocity flows which impact vulnerable catchments with little warning time and as such, result in complex flow dynamics which are difficult to replicate through modelling. The impacts of flash flooding can be made yet more severe by the transport of both natural and anthropogenic debris, ranging from tree trunks to vehicles, wheelie bins and even storage containers, the effects of which have been clearly evident during recent UK flooding. This cargo of debris can have wide reaching effects and result in actual flood impacts which diverge from those predicted. A build-up of debris may lead to partial channel blockage and potential flow rerouting through urban centres. Build-up at bridges and river structures also leads to increased hydraulic loading which may result in damage and possible structural failure. Predicting the impacts of debris transport; however, is difficult as conventional hydrodynamic modelling schemes do not intrinsically include floating debris within their calculations. Subsequently a new tool has been developed using an emerging approach, which incorporates debris transport through the coupling of two existing modelling techniques. A 1D hydrodynamic modelling scheme has here been coupled with a 2D discrete element scheme to form a new modelling tool which predicts the motion and flow-interaction of floating debris. Hydraulic forces arising from flow around the object are applied to instigate its motion. Likewise, an equivalent opposing force is applied to fluid cells, enabling backwater effects to be simulated. Shock capturing capabilities make the tool applicable to predicting the complex flow dynamics associated with flash flooding. The modelling scheme has been applied to experimental case studies where cylindrical wooden dowels are transported by a dam-break wave. These case studies enable validation of the tool's shock capturing capabilities and the coupling technique applied between the two numerical

  15. The impact of vaccination and patient characteristics on influenza vaccination uptake of elderly people: A discrete choice experiment.

    PubMed

    de Bekker-Grob, Esther W; Veldwijk, Jorien; Jonker, Marcel; Donkers, Bas; Huisman, Jan; Buis, Sylvia; Swait, Joffre; Lancsar, Emily; Witteman, Cilia L M; Bonsel, Gouke; Bindels, Patrick

    2018-03-07

    To improve information for patients and to facilitate a vaccination coverage that is in line with the EU and World Health Organization goals, we aimed to quantify how vaccination and patient characteristics impact on influenza vaccination uptake of elderly people. An online discrete choice experiment (DCE) was conducted among 1261 representatives of the Dutch general population aged 60 years or older. In the DCE, we used influenza vaccination scenarios based on five vaccination characteristics: effectiveness, risk of severe side effects, risk of mild side effects, protection duration, and absorption time. A heteroscedastic multinomial logit model was used, taking scale and preference heterogeneity (based on 19 patient characteristics) into account. Vaccination and patient characteristics both contributed to explain influenza vaccination uptake. Assuming a base case respondent and a realistic vaccination scenario, the predicted uptake was 58%. One-way changes in vaccination characteristics and patient characteristics changed this uptake from 46% up to 61% and from 37% up to 95%, respectively. The strongest impact on vaccination uptake was whether the patient had been vaccinated last year, whether s/he had experienced vaccination side effects, and the patient's general attitude towards vaccination. Although vaccination characteristics proved to influence influenza vaccination uptake, certain patient characteristics had an even higher impact on influenza vaccination uptake. Policy makers and general practitioners can use these insights to improve their communication plans and information regarding influenza vaccination for individuals aged 60 years or older. For instance, physicians should focus more on patients who had experienced side effects due to vaccination in the past, and policy makers should tailor the standard information folder to patients who had been vaccinated last year and to patient who had not. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. Application of discrete choice experiments to enhance stakeholder engagement as a strategy for advancing implementation: a systematic review.

    PubMed

    Salloum, Ramzi G; Shenkman, Elizabeth A; Louviere, Jordan J; Chambers, David A

    2017-11-23

    One of the key strategies to successful implementation of effective health-related interventions is targeting improvements in stakeholder engagement. The discrete choice experiment (DCE) is a stated preference technique for eliciting individual preferences over hypothetical alternative scenarios that is increasingly being used in health-related applications. DCEs are a dynamic approach to systematically measure health preferences which can be applied in enhancing stakeholder engagement. However, a knowledge gap exists in characterizing the extent to which DCEs are used in implementation science. We conducted a systematic literature search (up to December 2016) of the English literature to identify and describe the use of DCEs in engaging stakeholders as an implementation strategy. We searched the following electronic databases: MEDLINE, Econlit, PsychINFO, and the CINAHL using mesh terms. Studies were categorized according to application type, stakeholder(s), healthcare setting, and implementation outcome. Seventy-five publications were selected for analysis in this systematic review. Studies were categorized by application type: (1) characterizing demand for therapies and treatment technologies (n = 32), (2) comparing implementation strategies (n = 22), (3) incentivizing workforce participation (n = 11), and (4) prioritizing interventions (n = 10). Stakeholders included providers (n = 27), patients (n = 25), caregivers (n = 5), and administrators (n = 2). The remaining studies (n = 16) engaged multiple stakeholders (i.e., combination of patients, caregivers, providers, and/or administrators). The following implementation outcomes were discussed: acceptability (n = 75), appropriateness (n = 34), adoption (n = 19), feasibility (n = 16), and fidelity (n = 3). The number of DCE studies engaging stakeholders as an implementation strategy has been increasing over the past decade. As DCEs are more widely used as a

  17. How to value protection from natural hazards - a step-by-step discrete choice approach

    NASA Astrophysics Data System (ADS)

    Olschewski, R.

    2013-04-01

    In mountainous regions, forests play a crucial role in protecting the local population from natural hazards. In cases where existing forests are destroyed, e.g. by wind throws or diseases, the protection function has to be restored through technical measures. To determine the willingness to pay (WTP) for protection against avalanches, a choice experiment has been conducted and different experiment specifications have been tested to determine possible impacts on the results. The present study contributes to a comprehensive assessment of protection measures, and helps to identify efficient solutions based on the judgement of the people potentially endangered by natural hazards. The stepwise approach has the advantage to gradually check data fit, thereby didactically showing an operational way of dealing with different model specifications. The detailed case study can serve as a manual for conducting choice experiments with a similar focus and demonstrates the suitability and caveats of this approach to value protection from natural hazards in general.

  18. The impact of flavour, device type and warning messages on youth preferences for electronic nicotine delivery systems: evidence from an online discrete choice experiment.

    PubMed

    Shang, Ce; Huang, Jidong; Chaloupka, Frank J; Emery, Sherry L

    2017-11-02

    To examine the impact of flavour, device type and health warning messages on youth preference for electronic nicotine delivery systems (ENDS), and to provide evidence and data to inform the Food and Drug Administration's potential regulatory actions on ENDS. An online discrete choice experiment was conducted in September 2015. Each participant was given nine choice sets and asked to choose one out of two alternative ENDS products, with varying characteristics in three attributes (flavour, device type and warning message). The impact of the attributes on the probability of choosing ENDS was analysed using conditional and nested logit regressions, controlling for individual sociodemographic characteristics and current smoking status. A general population sample of 515 participants (50 ever-users and 465 never-users of ENDS) aged 14-17 years were recruited to complete the experiment using an online panel. Fruit/sweets/beverage flavours significantly increase the probability of choosing ENDS among youth (p<0.01 for never-users and <0.1 for ever-users) and flavour has the most pronounced impact among three attributes. Among never-users, menthol flavour also increases (p<0.05) the probability of choosing ENDS compared with tobacco flavour. Vaping devices that are modifiable, compared with cigarette-like e-cigarettes, increase (p<0.05) the probability of choosing ENDS among adolescent never-users. Warning messages reduce (p<0.01) the probability of choosing ENDS among never-users. Restricting fruit/sweets/beverage flavours in ENDS, regulating modifiable vaping devices and adopting strong health warning messages may reduce the uptake of ENDS among youth. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  19. Street characteristics preferred for transportation walking among older adults: a choice-based conjoint analysis with manipulated photographs.

    PubMed

    Van Cauwenberg, Jelle; De Bourdeaudhuij, Ilse; Clarys, Peter; Nasar, Jack; Salmon, Jo; Goubert, Liesbet; Deforche, Benedicte

    2016-01-16

    Knowledge about the relationships between micro-scale environmental factors and older adults' walking for transport is limited and inconsistent. This is probably due to methodological limitations, such as absence of an accurate neighborhood definition, lack of environmental heterogeneity, environmental co-variation, and recall bias. Furthermore, most previous studies are observational in nature. We aimed to address these limitations by investigating the effects of manipulating photographs on micro-scale environmental factors on the appeal of a street for older adults' transportation walking. Secondly, we used latent class analysis to examine whether subgroups could be identified that have different environmental preferences for transportation walking. Thirdly, we investigated whether these subgroups differed in socio-demographic, functional and psychosocial characteristics, current level of walking and environmental perceptions of their own street. Data were collected among 1131 Flemish older adults through an online (n = 940) or an interview version of the questionnaire (n = 191). This questionnaire included a choice-based conjoint exercise with manipulated photographs of a street. These manipulated photographs originated from one panoramic photograph of an existing street that was manipulated on nine environmental attributes. Participants chose which of two presented streets they would prefer to walk for transport. In the total sample, sidewalk evenness had by far the greatest appeal for transportation walking. The other environmental attributes were less important. Four subgroups that differed in their environmental preferences for transportation walking were identified. In the two largest subgroups (representing 86% of the sample) sidewalk evenness was the most important environmental attribute. In the two smaller subgroups (each comprising 7% of the sample), traffic volume and speed limit were the most important environmental attributes for one, and

  20. A WENO-Limited, ADER-DT, Finite-Volume Scheme for Efficient, Robust, and Communication-Avoiding Multi-Dimensional Transport

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Norman, Matthew R

    2014-01-01

    The novel ADER-DT time discretization is applied to two-dimensional transport in a quadrature-free, WENO- and FCT-limited, Finite-Volume context. Emphasis is placed on (1) the serial and parallel computational properties of ADER-DT and this framework and (2) the flexibility of ADER-DT and this framework in efficiently balancing accuracy with other constraints important to transport applications. This study demonstrates a range of choices for the user when approaching their specific application while maintaining good parallel properties. In this method, genuine multi-dimensionality, single-step and single-stage time stepping, strict positivity, and a flexible range of limiting are all achieved with only one parallel synchronizationmore » and data exchange per time step. In terms of parallel data transfers per simulated time interval, this improves upon multi-stage time stepping and post-hoc filtering techniques such as hyperdiffusion. This method is evaluated with standard transport test cases over a range of limiting options to demonstrate quantitatively and qualitatively what a user should expect when employing this method in their application.« less

  1. Stokes phenomena in discrete Painlevé I.

    PubMed

    Joshi, N; Lustri, C J

    2015-05-08

    In this study, we consider the asymptotic behaviour of the first discrete Painlevé equation in the limit as the independent variable becomes large. Using an asymptotic series expansion, we identify two types of solutions which are pole-free within some sector of the complex plane containing the positive real axis. Using exponential asymptotic techniques, we determine Stokes phenomena effects present within these solutions, and hence the regions in which the asymptotic series expression is valid. From a careful analysis of the switching behaviour across Stokes lines, we find that the first type of solution is uniquely defined, while the second type contains two free parameters, and that the region of validity may be extended for appropriate choice of these parameters.

  2. Valuing Health Using Time Trade-Off and Discrete Choice Experiment Methods: Does Dimension Order Impact on Health State Values?

    PubMed

    Mulhern, Brendan; Shah, Koonal; Janssen, Mathieu F Bas; Longworth, Louise; Ibbotson, Rachel

    2016-01-01

    Health states defined by multiattribute instruments such as the EuroQol five-dimensional questionnaire with five response levels (EQ-5D-5L) can be valued using time trade-off (TTO) or discrete choice experiment (DCE) methods. A key feature of the tasks is the order in which the health state dimensions are presented. Respondents may use various heuristics to complete the tasks, and therefore the order of the dimensions may impact on the importance assigned to particular states. To assess the impact of different EQ-5D-5L dimension orders on health state values. Preferences for EQ-5D-5L health states were elicited from a broadly representative sample of members of the UK general public. Respondents valued EQ-5D-5L health states using TTO and DCE methods across one of three dimension orderings via face-to-face computer-assisted personal interviews. Differences in mean values and the size of the health dimension coefficients across the arms were compared using difference testing and regression analyses. Descriptive analysis suggested some differences between the mean TTO health state values across the different dimension orderings, but these were not systematic. Regression analysis suggested that the magnitude of the dimension coefficients differs across the different dimension orderings (for both TTO and DCE), but there was no clear pattern. There is some evidence that the order in which the dimensions are presented impacts on the coefficients, which may impact on the health state values provided. The order of dimensions is a key consideration in the design of health state valuation studies. Copyright © 2016. Published by Elsevier Inc.

  3. What matters in type 2 diabetes mellitus oral treatment? A discrete choice experiment to evaluate patient preferences.

    PubMed

    Mühlbacher, Axel; Bethge, Susanne

    2016-12-01

    The aim of this empirical study is to evaluate patient preferences for different characteristics of oral type 2 diabetes mellitus (T2DM) treatment. As T2DM treatment requires strict adherence, patient needs and preferences should be taken into consideration. Based on a qualitative and quantitative analysis, a discrete choice experiment (DCE) was applied to identify patient preferences. Apart from six identical attributes (adjustment of glycated hemoglobin [HbA1c], prevention of hypoglycemia, risk of genital infection, risk of gastrointestinal problems, risk of urinary tract infection, and weight change), one continuous variable of either "additional healthy life years" (AHY) or "additional costs" attribute (AC) was included. The DCE was conducted using a fractional factorial design, and the statistical data analysis used random effect logit models. In total, N = 626 (N = 318 AHY + N = 308 AC) T2DM patients participated in the survey. The estimation revealed a clear dominance for prevention of hypoglycemia (coefficient 0.937) and adjustment of HbA1c (coefficient 0.541). The attributes, "additional healthy life years" (coefficient 0.458) or "additional costs" (coefficient 0.420), were in the middle rank and both of significant impact. The side effects, risk of genital infection (coefficient 0.301), risk of gastrointestinal problems (coefficient 0.296), and risk of urinary tract infection (coefficient 0.241) followed in this respective order. Possible weight change (coefficient 0.047) was of less importance (last rank) to the patients in this evaluation. These survey results demonstrate how much a (hypothetical) T2DM oral treatment characteristic affects the treatment decision. The preference data can be used for risk-benefit assessment, cost-benefit assessment, and the establishment of patient-oriented evidence. Understanding how patients perceive and value different aspects of diabetes oral treatment is vital to the optimal design and evaluation of treatment

  4. An Empirical Comparison of Discrete Choice Experiment and Best-Worst Scaling to Estimate Stakeholders' Risk Tolerance for Hip Replacement Surgery.

    PubMed

    van Dijk, Joris D; Groothuis-Oudshoorn, Catharina G M; Marshall, Deborah A; IJzerman, Maarten J

    2016-06-01

    Previous studies have been inconclusive regarding the validity and reliability of preference elicitation methods. The aim of this study was to compare the metrics obtained from a discrete choice experiment (DCE) and profile-case best-worst scaling (BWS) with respect to hip replacement. We surveyed the general US population of men aged 45 to 65 years, and potentially eligible for hip replacement surgery. The survey included sociodemographic questions, eight DCE questions, and twelve BWS questions. Attributes were the probability of a first and second revision, pain relief, ability to participate in sports and perform daily activities, and length of hospital stay. Conditional logit analysis was used to estimate attribute weights, level preferences, and the maximum acceptable risk (MAR) for undergoing revision surgery in six hypothetical treatment scenarios with different attribute levels. A total of 429 (96%) respondents were included. Comparable attribute weights and level preferences were found for both BWS and DCE. Preferences were greatest for hip replacement surgery with high pain relief and the ability to participate in sports and perform daily activities. Although the estimated MARs for revision surgery followed the same trend, the MARs were systematically higher in five of the six scenarios using DCE. This study confirms previous findings that BWS or DCEs are comparable in estimating attribute weights and level preferences. However, the risk tolerance threshold based on the estimation of MAR differs between these methods, possibly leading to inconsistency in comparing treatment scenarios. Copyright © 2016 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  5. Children's route choice during active transportation to school: difference between shortest and actual route.

    PubMed

    Dessing, Dirk; de Vries, Sanne I; Hegeman, Geertje; Verhagen, Evert; van Mechelen, Willem; Pierik, Frank H

    2016-04-12

    The purpose of this study is to increase our understanding of environmental correlates that are associated with route choice during active transportation to school (ATS) by comparing characteristics of actual walking and cycling routes between home and school with the shortest possible route to school. Children (n = 184; 86 boys, 98 girls; age range: 8-12 years) from seven schools in suburban municipalities in the Netherlands participated in the study. Actual walking and cycling routes to school were measured with a GPS-device that children wore during an entire school week. Measurements were conducted in the period April-June 2014. Route characteristics for both actual and shortest routes between home and school were determined for a buffer of 25 m from the routes and divided into four categories: Land use (residential, commercial, recreational, traffic areas), Aesthetics (presence of greenery/natural water ways along route), Traffic (safety measures such as traffic lights, zebra crossings, speed bumps) and Type of street (pedestrian, cycling, residential streets, arterial roads). Comparison of characteristics of shortest and actual routes was performed with conditional logistic regression models. Median distance of the actual walking routes was 390.1 m, whereas median distance of actual cycling routes was 673.9 m. Actual walking and cycling routes were not significantly longer than the shortest possible routes. Children mainly traveled through residential areas on their way to school (>80% of the route). Traffic lights were found to be positively associated with route choice during ATS. Zebra crossings were less often present along the actual routes (walking: OR = 0.17, 95% CI = 0.05-0.58; cycling: OR = 0.31, 95% CI = 0.14-0.67), and streets with a high occurrence of accidents were less often used during cycling to school (OR = 0.57, 95% CI = 0.43-0.76). Moreover, percentage of visible surface water along the actual route was higher

  6. Addressing health workforce distribution concerns: a discrete choice experiment to develop rural retention strategies in Cameroon

    PubMed Central

    Robyn, Paul Jacob; Shroff, Zubin; Zang, Omer Ramses; Kingue, Samuel; Djienouassi, Sebastien; Kouontchou, Christian; Sorgho, Gaston

    2015-01-01

    Background: Nearly every nation in the world faces shortages of health workers in remote areas. Cameroon is no exception to this. The Ministry of Public Health (MoPH) is currently considering several rural retention strategies to motivate qualified health personnel to practice in remote rural areas. Methods: To better calibrate these mechanisms and to develop evidence-based retention strategies that are attractive and motivating to health workers, a Discrete Choice Experiment (DCE) was conducted to examine what job attributes are most attractive and important to health workers when considering postings in remote areas. The study was carried out between July and August 2012 among 351 medical students, nursing students and health workers in Cameroon. Mixed logit models were used to analyze the data. Results: Among medical and nursing students a rural retention bonus of 75% of base salary (aOR= 8.27, 95% CI: 5.28-12.96, P< 0.001) and improved health facility infrastructure (aOR= 3.54, 95% CI: 2.73-4.58) respectively were the attributes with the largest effect sizes. Among medical doctors and nurse aides, a rural retention bonus of 75% of base salary was the attribute with the largest effect size (medical doctors aOR= 5.60, 95% CI: 4.12-7.61, P< 0.001; nurse aides aOR= 4.29, 95% CI: 3.11-5.93, P< 0.001). On the other hand, improved health facility infrastructure (aOR= 3.56, 95% CI: 2.75-4.60, P< 0.001), was the attribute with the largest effect size among the state registered nurses surveyed. Willingness-to-Pay (WTP) estimates were generated for each health worker cadre for all the attributes. Preference impact measurements were also estimated to identify combination of incentives that health workers would find most attractive. Conclusion: Based on these findings, the study recommends the introduction of a system of substantial monetary bonuses for rural service along with ensuring adequate and functional equipment and uninterrupted supplies. By focusing on the

  7. Patient Preferences for Injectable Treatments for Multiple Sclerosis in the United States: A Discrete-Choice Experiment.

    PubMed

    Poulos, Christine; Kinter, Elizabeth; Yang, Jui-Chen; Bridges, John F P; Posner, Joshua; Reder, Anthony T

    2016-04-01

    Patients' perceptions and experiences of medication efficacy, medication adverse events, dosing frequency, and dosing complexity have been found to influence adherence to injectable disease-modifying treatments (DMTs) in patients with multiple sclerosis (MS). The aim of this study was to quantify patient preferences for features of injectable DMTs for MS. Adult patients in the United States (US) with a self-reported diagnosis of MS completed an online discrete-choice experiment survey to assess preference for a number of features of a hypothetical injectable DMT. Patients chose hypothetical treatments in paired comparisons, where each treatment was described by features or attributes, including the number of years until disability progression, the number of relapses in the next 4 years, injection time, the frequency of injections, the occurrence of flu-like symptoms (FLS), and severity of injection-site reactions. Random-parameters logit regression parameters were used to calculate preference weights of attribute levels and the relative importance of changes in treatment features. Of the 205 patients who completed the survey, 192 provided sufficient data for analysis. The results indicated a broad range of tradeoffs that patients would be willing to make. With regard to this, the relative importance of an improvement in the number of years until disability progression from 1 to 2 (i.e., vertical distance between preference weights for these attribute levels) was 0.9 [95% confidence interval (CI) 0.5-1.2], the relative importance of this change was approximately equivalent to that of an improvement from 12 injections per month to two (mean 0.8, 95% CI 0.4-1.2), or approximately equivalent to a decrease from four to one relapses in the next 4 years (mean 0.8, 95% CI 0.5-1.2), or FLS 3 days after every injection to 3 days after some injections (mean 1.0, 95% CI 0.6-1.4). These results suggest that an improvement in treatment efficacy may be as important as a reduction

  8. Willingness to pay for flexible working conditions of people with type 2 diabetes: discrete choice experiments.

    PubMed

    Nexo, M A; Cleal, B; Hagelund, Lise; Willaing, I; Olesen, K

    2017-12-15

    The increasing number of people with chronic diseases challenges workforce capacity. Type 2 diabetes (T2D) can have work-related consequences, such as early retirement. Laws of most high-income countries require workplaces to provide accommodations to enable people with chronic disabilities to manage their condition at work. A barrier to successful implementation of such accommodations can be lack of co-workers' willingness to support people with T2D. This study aimed to examine the willingness to pay (WTP) of people with and without T2D for five workplace initiatives that help individuals with type 2 diabetes manage their diabetes at work. Three samples with employed Danish participants were drawn from existing online panels: a general population sample (n = 600), a T2D sample (n = 693), and a matched sample of people without diabetes (n = 539). Participants completed discrete choice experiments eliciting their WTP (reduction in monthly salary, €/month) for five hypothetical workplace initiatives: part-time job, customized work, extra breaks with pay, and time off for medical consultations with and without pay. WTP was estimated by conditional logits models. Bootstrapping was used to estimate confidence intervals for WTP. There was an overall WTP for all initiatives. Average WTP for all attributes was 34 €/month (95% confidence interval [CI]: 27-43] in the general population sample, 32 €/month (95% CI: 26-38) in the T2D sample, and 55 €/month (95% CI: 43-71) in the matched sample. WTP for additional breaks with pay was considerably lower than for the other initiatives in all samples. People with T2D had significantly lower WTP than people without diabetes for part-time work, customized work, and time off without pay, but not for extra breaks or time off with pay. For people with and without T2D, WTP was present for initiatives that could improve management of diabetes at the workplace. WTP was lowest among people with T2D. Implementation of these

  9. Obligatory Effort [Hishtadlut] as an Explanatory Model: A Critique of Reproductive Choice and Control.

    PubMed

    Teman, Elly; Ivry, Tsipy; Goren, Heela

    2016-06-01

    Studies on reproductive technologies often examine women's reproductive lives in terms of choice and control. Drawing on 48 accounts of procreative experiences of religiously devout Jewish women in Israel and the US, we examine their attitudes, understandings and experiences of pregnancy, reproductive technologies and prenatal testing. We suggest that the concept of hishtadlut-"obligatory effort"-works as an explanatory model that organizes Haredi women's reproductive careers and their negotiations of reproductive technologies. As an elastic category with negotiable and dynamic boundaries, hishtadlut gives ultra-orthodox Jewish women room for effort without the assumption of control; it allows them to exercise discretion in relation to medical issues without framing their efforts in terms of individual choice. Haredi women hold themselves responsible for making their obligatory effort and not for pregnancy outcomes. We suggest that an alternative paradigm to autonomous choice and control emerges from cosmological orders where reproductive duties constitute "obligatory choices."

  10. A discrete choice experiment to determine facility-based delivery services desired by women and men in rural Ethiopia

    PubMed Central

    Beam, Nancy K; Bekele Dadi, Gezehegn; Rankin, Sally H; Weiss, Sandra; Cooper, Bruce; Thompson, Lisa M

    2018-01-01

    Objectives Despite global efforts to increase facility-based delivery (FBD), 90% of women in rural Ethiopia deliver at home without a skilled birth attendant. Men have an important role in increasing FBD due to their decision-making power, but this is largely unexplored. This study aimed to determine the FBD care attributes preferred by women and men, and whether poverty or household decision-making are associated with choice to deliver in a facility. Setting and participants We conducted a cross-sectional discrete choice experiment in 109 randomly selected households in rural Ethiopia in September–October 2015. We interviewed women who were pregnant or who had a child <2 years old and their male partners. Results Both women and men preferred health facilities where medications and supplies were available (OR=3.08; 95% CI 2.03 to 4.67 and OR=2.68; 95% CI 1.79 to 4.02, respectively), a support person was allowed in the delivery room (OR=1.69; 95% CI 1.37 to 2.07 and OR=1.74; 95% CI 1.42 to 2.14, respectively) and delivery cost was low (OR=1.15 95% CI 1.12 to 1.18 and OR=1.14; 95% CI 1.11 to 1.17, respectively). Women valued free ambulance service (OR=1.37; 95% CI 1.09 to 1.70), while men favoured nearby facilities (OR=1.09; 95% CI 1.06 to 1.13) with friendly providers (OR=1.30; 95% CI 1.03 to 1.64). Provider preferences were complex. Neither women nor men preferred female doctors to health extension workers (HEW) (OR=0.92; 95% CI 0.59 to 1.42 and OR=0.74; 95% CI 0.47 to 1.14, respectively), male doctors to HEW (OR=1.33; 95% CI 0.89 to 1.99 and OR=0.75; 95% CI 0.50 to 1.12, respectively) or female over male nurses (OR=0.68; 95% CI 0.94 to 1.71 and OR=1.03; 95% CI 0.77 to 2.94, respectively). While both women and men preferred male nurses to HEW (OR=1.86; 95% CI 1.23 to 2.80 and OR=1.95; 95% CI 1.30 to 2.95, respectively), men (OR=1.89; 95% CI 1.29 to 2.78), but not women (OR=1.47; 95% CI 1.00 to 2.13) preferred HEW to female

  11. Discrete-Roughness-Element-Enhanced Swept-Wing Natural Laminar Flow at High Reynolds Numbers

    NASA Technical Reports Server (NTRS)

    Malik, Mujeeb; Liao, Wei; Li, Fei; Choudhari, Meelan

    2015-01-01

    Nonlinear parabolized stability equations and secondary-instability analyses are used to provide a computational assessment of the potential use of the discrete-roughness-element technology for extending swept-wing natural laminar flow at chord Reynolds numbers relevant to transport aircraft. Computations performed for the boundary layer on a natural-laminar-flow airfoil with a leading-edge sweep angle of 34.6 deg, freestream Mach number of 0.75, and chord Reynolds numbers of 17 × 10(exp 6), 24 × 10(exp 6), and 30 × 10(exp 6) suggest that discrete roughness elements could delay laminar-turbulent transition by about 20% when transition is caused by stationary crossflow disturbances. Computations show that the introduction of small-wavelength stationary crossflow disturbances (i.e., discrete roughness element) also suppresses the growth of most amplified traveling crossflow disturbances.

  12. Fourth order discretization of anisotropic heat conduction operator

    NASA Astrophysics Data System (ADS)

    Krasheninnikova, Natalia; Chacon, Luis

    2008-11-01

    In magnetized plasmas, heat conduction plays an important role in such processes as energy confinement, turbulence, and a number of instabilities. As a consequence of the presence of a magnetic field, heat transport is strongly anisotropic, with energy flowing preferentially along the magnetic field direction. This in turn results in parallel and perpendicular heat conduction coefficients being separated by orders of magnitude. The computational difficulties in treating such heat conduction anisotropies are significant, as perpendicular dynamics numerically is polluted by the parallel one. In this work, we report on progress of the implementation of a fourth order, conservative finite volume discretization scheme for the anisotropic heat conduction operator into the extended MHD code PIXIE3D [1]. We will demonstrate its spatial discretization accuracy and its effectiveness with two physical applications of interest, both of which feature a strong sensitivity to the heat conduction anisotropy: the thermal instability and the neoclassical tearing mode. [1] L. Chacon Phys. Plasmas 15, 056103 (2008)

  13. Transportation Energy Futures: Freight Transportation Modal Shares: Scenarios for a Low-Carbon Future

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Brogan, J. J.; Aeppli, A. E.; Brown, D. F.

    2013-03-01

    Freight transportation modes—truck, rail, water, air, and pipeline—each serve a distinct share of the freight transportation market. A variety of factors influence the modes chosen by shippers, carriers, and others involved in freight supply chains. Analytical methods can be used to project future modal shares, and federal policy actions could influence future freight mode choices. This report considers how these topics have been addressed in existing literature and offers insights on federal policy decisions with the potential to prompt mode choices that reduce energy use and greenhouse gas emissions.

  14. Coherent virtual absorption for discretized light

    NASA Astrophysics Data System (ADS)

    Longhi, S.

    2018-05-01

    Coherent virtual absorption (CVA) is a recently-introduced phenomenon for which exponentially growing waves incident onto a conservative optical medium are neither reflected nor transmitted, at least transiently. CVA has been associated to complex zeros of the scattering matrix and can be regarded as the time reversal of the decay process of a quasi-mode sustained by the optical medium. Here we consider CVA for discretized light transport in coupled resonator optical waveguides or waveguide arrays and show that a distinct kind of CVA, which is not related to complex zero excitation of quasi-modes, can be observed. This result suggests that scattering matrix analysis can not fully capture CVA phenomena.

  15. MEDICAL EXPENDITURE RISK AND HOUSEHOLD PORTFOLIO CHOICE

    PubMed Central

    Goldman, Dana

    2013-01-01

    Medical expenses are an increasingly important contributor to household financial risk. We examine the effect of medical expenditure risk on the willingness of Medicare beneficiaries to hold risky assets. Using a discrete factor maximum likelihood method to address the endogeneity of insurance choices, we find that having a moderately protective Medigap or employer supplemental policy increases risky asset holding by 7.1 percentage points relative to those without supplemental coverage, while participation in a highly protective Medicare HMO increases risky asset holding by 13.0 percentage points. Our results highlight an important link between the availability of health insurance and financial behavior. PMID:23997424

  16. Numerical simulation of freshwater/seawater interaction in a dual-permeability karst system with conduits: the development of discrete-continuum VDFST-CFP model

    NASA Astrophysics Data System (ADS)

    Xu, Zexuan; Hu, Bill

    2016-04-01

    Dual-permeability karst aquifers of porous media and conduit networks with significant different hydrological characteristics are widely distributed in the world. Discrete-continuum numerical models, such as MODFLOW-CFP and CFPv2, have been verified as appropriate approaches to simulate groundwater flow and solute transport in numerical modeling of karst hydrogeology. On the other hand, seawater intrusion associated with fresh groundwater resources contamination has been observed and investigated in numbers of coastal aquifers, especially under conditions of sea level rise. Density-dependent numerical models including SEAWAT are able to quantitatively evaluate the seawater/freshwater interaction processes. A numerical model of variable-density flow and solute transport - conduit flow process (VDFST-CFP) is developed to provide a better description of seawater intrusion and submarine groundwater discharge in a coastal karst aquifer with conduits. The coupling discrete-continuum VDFST-CFP model applies Darcy-Weisbach equation to simulate non-laminar groundwater flow in the conduit system in which is conceptualized and discretized as pipes, while Darcy equation is still used in continuum porous media. Density-dependent groundwater flow and solute transport equations with appropriate density terms in both conduit and porous media systems are derived and numerically solved using standard finite difference method with an implicit iteration procedure. Synthetic horizontal and vertical benchmarks are created to validate the newly developed VDFST-CFP model by comparing with other numerical models such as variable density SEAWAT, couplings of constant density groundwater flow and solute transport MODFLOW/MT3DMS and discrete-continuum CFPv2/UMT3D models. VDFST-CFP model improves the simulation of density dependent seawater/freshwater mixing processes and exchanges between conduit and matrix. Continuum numerical models greatly overestimated the flow rate under turbulent flow

  17. Bounds for the price of discrete arithmetic Asian options

    NASA Astrophysics Data System (ADS)

    Vanmaele, M.; Deelstra, G.; Liinev, J.; Dhaene, J.; Goovaerts, M. J.

    2006-01-01

    In this paper the pricing of European-style discrete arithmetic Asian options with fixed and floating strike is studied by deriving analytical lower and upper bounds. In our approach we use a general technique for deriving upper (and lower) bounds for stop-loss premiums of sums of dependent random variables, as explained in Kaas et al. (Ins. Math. Econom. 27 (2000) 151-168), and additionally, the ideas of Rogers and Shi (J. Appl. Probab. 32 (1995) 1077-1088) and of Nielsen and Sandmann (J. Financial Quant. Anal. 38(2) (2003) 449-473). We are able to create a unifying framework for European-style discrete arithmetic Asian options through these bounds, that generalizes several approaches in the literature as well as improves the existing results. We obtain analytical and easily computable bounds. The aim of the paper is to formulate an advice of the appropriate choice of the bounds given the parameters, investigate the effect of different conditioning variables and compare their efficiency numerically. Several sets of numerical results are included. We also discuss hedging using these bounds. Moreover, our methods are applicable to a wide range of (pricing) problems involving a sum of dependent random variables.

  18. Alternative Reinforcer Response Cost Impacts Methamphetamine Choice in Humans

    PubMed Central

    Bennett, J. Adam; Stoops, William W.; Rush, Craig R.

    2012-01-01

    Methamphetamine use disorders are a persistent public health concern. Behavioral treatments have demonstrated that providing access to non-drug alternative reinforcers reduces methamphetamine use. The purpose of this human laboratory experiment was to determine how changes in response cost for non-drug alternative reinforcers influenced methamphetamine choice. Seven subjects with past year histories of recreational stimulant use completed a placebo-controlled, crossover, double-blind protocol in which they first sampled doses of oral methamphetamine (0, 8 or 16 mg) and completed a battery of subject-rated and physiological measures. During subsequent sessions, subjects then made eight discrete choices between 1/8th of the sampled dose and an alternative reinforcer ($0.25). The response cost to earn a methamphetamine dose was always 500 responses (FR500). The response cost for the alternative reinforcer varied across sessions (FR500, FR1000, FR2000, FR3000). Methamphetamine functioned as a positive reinforcer and produced prototypical stimulant-like effects (e.g., elevated blood pressure, increased ratings of “Stimulated”). Choice for doses over money was sensitive to changes in response cost for alternative reinforcers in that more doses were taken at higher FR values than at lower FR values. Placebo choices changed as a function of alternative reinforcer response cost to a greater degree than active methamphetamine choices. These findings suggest that manipulating the effort necessary to earn alternative reinforcers could impact methamphetamine use. PMID:23046851

  19. A Study of Driver's Route Choice Behavior Based on Evolutionary Game Theory

    PubMed Central

    Jiang, Xiaowei; Ji, Yanjie; Deng, Wei

    2014-01-01

    This paper proposes a route choice analytic method that embeds cumulative prospect theory in evolutionary game theory to analyze how the drivers adjust their route choice behaviors under the influence of the traffic information. A simulated network with two alternative routes and one variable message sign is built to illustrate the analytic method. We assume that the drivers in the transportation system are bounded rational, and the traffic information they receive is incomplete. An evolutionary game model is constructed to describe the evolutionary process of the drivers' route choice decision-making behaviors. Here we conclude that the traffic information plays an important role in the route choice behavior. The driver's route decision-making process develops towards different evolutionary stable states in accordance with different transportation situations. The analysis results also demonstrate that employing cumulative prospect theory and evolutionary game theory to study the driver's route choice behavior is effective. This analytic method provides an academic support and suggestion for the traffic guidance system, and may optimize the travel efficiency to a certain extent. PMID:25610455

  20. A study of driver's route choice behavior based on evolutionary game theory.

    PubMed

    Jiang, Xiaowei; Ji, Yanjie; Du, Muqing; Deng, Wei

    2014-01-01

    This paper proposes a route choice analytic method that embeds cumulative prospect theory in evolutionary game theory to analyze how the drivers adjust their route choice behaviors under the influence of the traffic information. A simulated network with two alternative routes and one variable message sign is built to illustrate the analytic method. We assume that the drivers in the transportation system are bounded rational, and the traffic information they receive is incomplete. An evolutionary game model is constructed to describe the evolutionary process of the drivers' route choice decision-making behaviors. Here we conclude that the traffic information plays an important role in the route choice behavior. The driver's route decision-making process develops towards different evolutionary stable states in accordance with different transportation situations. The analysis results also demonstrate that employing cumulative prospect theory and evolutionary game theory to study the driver's route choice behavior is effective. This analytic method provides an academic support and suggestion for the traffic guidance system, and may optimize the travel efficiency to a certain extent.

  1. Colloid facilitated transport of lanthanides through discrete fractures in chalk

    NASA Astrophysics Data System (ADS)

    Tran, Emily; Klein Ben-David, Ofra; Teutsch, Nadya; Weisbrod, Noam

    2015-04-01

    Geological disposal of high-level radioactive waste is the internationally agreed-upon, long term solution for the disposal of long lived radionuclides and spent fuel. Eventually, corrosion of the waste canisters may lead to leakage of their hazardous contents, and the radionuclides can ultimately make their way into groundwater and pose a threat to the biosphere. Engineered bentonite barriers placed around nuclear waste repositories are generally considered sufficient to impede the transport of radionuclides from their storage location to the groundwater. However, colloidal-sized mobile bentonite particles eroding from these barriers have come under investigation as a potential transport vector for radionuclides sorbed to them. In addition, the presence of organic matter in groundwater has been shown to additionally facilitate the uptake of radionuclides by the clay colloids. This study aims to evaluate the transport behaviors of radionuclides in colloid-facilitated transport through a fractured chalk matrix and under geochemical conditions representative of the Negev desert, Israel. Lanthanides are considered an acceptable substitute to actinides for research on radionuclide transportation due to their similar chemical behavior. In this study, the migration of Ce both with and without colloidal particles was explored and compared to the migration of a conservative tracer (bromide). Tracer solutions containing known concentrations of Ce, bentonite colloids, humic acid and bromide were prepared in a matrix solution containing salt concentrations representative of that of the average rain water found in the Negev. These solutions were then injected into a flow system constructed around a naturally fractured chalk core. Samples were analyzed for Ce and Br using ICP-MS, and colloid concentrations were determined using spectrophotographic analysis. Breakthrough curves comparing the rates of transportation of each tracer were obtained, allowing for comparison of

  2. Public preferences for vaccination programmes during pandemics caused by pathogens transmitted through respiratory droplets - a discrete choice experiment in four European countries, 2013.

    PubMed

    Determann, Domino; Korfage, Ida J; Fagerlin, Angela; Steyerberg, Ewout W; Bliemer, Michiel C; Voeten, Helene A; Richardus, Jan Hendrik; Lambooij, Mattijs S; de Bekker-Grob, Esther W

    2016-06-02

    This study aims to quantify and compare preferences of citizens from different European countries for vaccination programme characteristics during pandemics, caused by pathogens which are transmitted through respiratory droplets. Internet panel members, nationally representative based on age, sex, educational level and region, of four European Union Member States (Netherlands, Poland, Spain, and Sweden, n = 2,068) completed an online discrete choice experiment. These countries, from different geographical areas of Europe, were chosen because of the availability of high-quality Internet panels and because of the cooperation between members of the project entitled Effective Communication in Outbreak Management: development of an evidence-based tool for Europe (ECOM). Data were analysed using panel latent class regression models. In the case of a severe pandemic scenario, vaccine effectiveness was the most important characteristic determining vaccination preference in all countries, followed by the body that advises on vaccination. In Sweden, the advice of family and/or friends and the advice of physicians strongly affected vaccine preferences, in contrast to Poland and Spain, where the advice of (international) health authorities was more decisive. Irrespective of pandemic scenario or vaccination programme characteristics, the predicted vaccination uptakes were lowest in Sweden, and highest in Poland. To increase vaccination uptake during future pandemics, the responsible authorities should align with other important stakeholders in the country and communicate in a coordinated manner.

  3. Convergent validity between a discrete choice experiment and a direct, open-ended method: comparison of preferred attribute levels and willingness to pay estimates.

    PubMed

    Marjon van der Pol; Shiell, Alan; Au, Flora; Johnston, David; Tough, Suzanne

    2008-12-01

    The Discrete Choice Experiment (DCE) has become increasingly popular as a method for eliciting patient or population preferences. If DCE estimates are to inform health policy, it is crucial that the answers they provide are valid. Convergent validity is tested in this paper by comparing the results of a DCE exercise with the answers obtained from direct, open-ended questions. The two methods are compared in terms of preferred attribute levels and willingness to pay (WTP) values. Face-to-face interviews were held with 292 women in Calgary, Canada. Similar values were found between the two methods with respect to preferred levels for two out of three of the attributes examined. The DCE predicted less well for levels outside the range than for levels inside the range reaffirming the importance of extensive piloting to ensure appropriate level range in DCEs. The mean WTP derived from the open-ended question was substantially lower than the mean derived from the DCE. However, the two sets of willingness to pay estimates were consistent with each other in that individuals who were willing to pay more in the open-ended question were also willing to pay more in the DCE. The difference in mean WTP values between the two approaches (direct versus DCE) demonstrates the importance of continuing research into the different biases present across elicitation methods.

  4. How to reform western care payment systems according to physicians, policy makers, healthcare executives and researchers: a discrete choice experiment.

    PubMed

    Kessels, Roselinde; Van Herck, Pieter; Dancet, Eline; Annemans, Lieven; Sermeus, Walter

    2015-05-06

    Many developed countries are reforming healthcare payment systems in order to limit costs and improve clinical outcomes. Knowledge on how different groups of professional stakeholders trade off the merits and downsides of healthcare payment systems is limited. Using a discrete choice experiment we asked a sample of physicians, policy makers, healthcare executives and researchers from Canada, Europe, Oceania, and the United States to choose between profiles of hypothetical outcomes on eleven healthcare performance objectives which may arise from a healthcare payment system reform. We used a Bayesian D-optimal design with partial profiles, which enables studying a large number of attributes, i.e. the eleven performance objectives, in the experiment. Our findings suggest that (a) moving from current payment systems to a value-based system is supported by physicians, despite an income trade-off, if effectiveness and long term cost containment improve. (b) Physicians would gain in terms of overall objective fulfillment in Eastern Europe and the US, but not in Canada, Oceania and Western Europe. Finally, (c) such payment reform more closely aligns the overall fulfillment of objectives between stakeholders such as physicians versus healthcare executives. Although the findings should be interpreted with caution due to the potential selection effects of participants, it seems that the value driven nature of newly proposed and/or introduced care payment reforms is more closely aligned with what stakeholders favor in some health systems, but not in others. Future studies, including the use of random samples, should examine the contextual factors that explain such differences in values and buy-in. C90, C99, E61, I11, I18, O57.

  5. Application of discrete choice experiment to assess farmers' willingness to report swine diseases in the Red River Delta region, Vietnam.

    PubMed

    Pham, Hoa T T; Peyre, Marisa; Trinh, Tuyen Quang; Nguyen, Oanh Cong; Vu, Ton Dinh; Rukkwamsuk, Theera; Antoine-Moussiaux, Nicolas

    2017-03-01

    A discrete choice experiment (DCE) is carried out to value socio-economic factors influencing the farmer's decision to report swine diseases and to assess the willingness of farmers to report swine diseases. Data were collected between March and July 2015 in two provinces in the Red River Delta, Northern Vietnam, from 196 pig producers by face-to face interview. A conditional logit model is used to measure the relative importance of the socio-economic factors and calculate the expected probability of disease reporting under changes of levels of these factors. Results of the study indicated that the likelihood of compensation and the type of culling implemented (all or only unrecovered pigs) are the two most important factors influencing farmer reporting. Compensation level, movement restriction and delay in compensation payment also have significant impacts on farmer's decision to report animal disease but they are not as important as the above factors. Three different scenarios including changes in six different factors (attributes) are tested to predict probability of animal disease reporting. Under the current situation (uncertainty of being compensated), only 4% of the farmers would report swine disease outbreak to the official surveillance system if the culling policy involves all pigs in affected farms. This number is increased to 26% if culling in affected farms is restricted to unrecovered pigs only. Ensuring certainty of compensation increases reporting probability by up to 50% and 90% if all or only unrecovered pigs are destroyed, respectively. The results of this study are important for improving the performance and sustainability of swine disease surveillance system in Vietnam. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Discrete exterior calculus discretization of incompressible Navier-Stokes equations over surface simplicial meshes

    NASA Astrophysics Data System (ADS)

    Mohamed, Mamdouh S.; Hirani, Anil N.; Samtaney, Ravi

    2016-05-01

    A conservative discretization of incompressible Navier-Stokes equations is developed based on discrete exterior calculus (DEC). A distinguishing feature of our method is the use of an algebraic discretization of the interior product operator and a combinatorial discretization of the wedge product. The governing equations are first rewritten using the exterior calculus notation, replacing vector calculus differential operators by the exterior derivative, Hodge star and wedge product operators. The discretization is then carried out by substituting with the corresponding discrete operators based on the DEC framework. Numerical experiments for flows over surfaces reveal a second order accuracy for the developed scheme when using structured-triangular meshes, and first order accuracy for otherwise unstructured meshes. By construction, the method is conservative in that both mass and vorticity are conserved up to machine precision. The relative error in kinetic energy for inviscid flow test cases converges in a second order fashion with both the mesh size and the time step.

  7. PREFACE: 4th Symposium on Prospects in the Physics of Discrete Symmetries (DISCRETE2014)

    NASA Astrophysics Data System (ADS)

    Di Domenico, Antonio; Mavromatos, Nick E.; Mitsou, Vasiliki A.; Skliros, Dimitri P.

    2015-07-01

    The DISCRETE 2014: Fourth Symposium in the Physics of Discrete Symmetries took place at King's College London, Strand Campus, London WC2R 2LS, from Tuesday, December 2 2014 till Saturday, December 6 2014. This is the fourth Edition of the DISCRETE conference series, which is a biannual event, having been held previously in Valencia (Discrete'08), Rome (Discrete2010) and Lisbon (Discrete2012). The topics covered at the DISCRETE series of conferences are: T, C, P, CP symmetries; accidental symmetries (B, L conservation); CPT symmetry, decoherence and entangled states, Lorentz symmetry breaking (phenomenology and current bounds); neutrino mass and mixing; implications for cosmology and astroparticle physics, dark matter searches; experimental prospects at LHC, new facilities. In DISCRETE 2014 we have also introduced two new topics: cosmological aspects of non-commutative space-times as well as PT symmetric Hamiltonians (non-Hermitian but with real eigenvalues), a topic that has wide applications in particle physics and beyond. The conference was opened by the King's College London Vice Principal on Research and Innovation, Mr Chris Mottershead, followed by a welcome address by the Chair of DISCRETE 2014 (Professor Nick E. Mavromatos). After these introductory talks, the scientific programme of the DISCRETE 2014 symposium started. Following the tradition of DISCRETE series of conferences, the talks (138 in total) were divided into plenary-review talks (25), invited research talks (50) and shorter presentations (63) — selected by the conveners of each session in consultation with the organisers — from the submitted abstracts. We have been fortunate to have very high-quality, thought stimulating and interesting talks at all levels, which, together with the discussions among the participants, made the conference quite enjoyable. There were 152 registered participants for the event.

  8. Discrete and continuous dynamics modeling of a mass moving on a flexible structure

    NASA Technical Reports Server (NTRS)

    Herman, Deborah Ann

    1992-01-01

    A general discrete methodology for modeling the dynamics of a mass that moves on the surface of a flexible structure is developed. This problem was motivated by the Space Station/Mobile Transporter system. A model reduction approach is developed to make the methodology applicable to large structural systems. To validate the discrete methodology, continuous formulations are also developed. Three different systems are examined: (1) simply-supported beam, (2) free-free beam, and (3) free-free beam with two points of contact between the mass and the flexible beam. In addition to validating the methodology, parametric studies were performed to examine how the system's physical properties affect its dynamics.

  9. What factors are critical to attracting NHS foundation doctors into specialty or core training? A discrete choice experiment.

    PubMed

    Scanlan, Gillian Marion; Cleland, Jennifer; Johnston, Peter; Walker, Kim; Krucien, Nicolas; Skåtun, Diane

    2018-03-12

    Multiple personal and work-related factors influence medical trainees' career decision-making. The relative value of these diverse factors is under-researched, yet this intelligence is crucially important for informing medical workforce planning and retention and recruitment policies. Our aim was to investigate the relative value of UK doctors' preferences for different training post characteristics during the time period when they either apply for specialty or core training or take time out. We developed a discrete choice experiment (DCE) specifically for this population. The DCE was distributed to all Foundation Programme Year 2 (F2) doctors across Scotland as part of the National Career Destination Survey in June 2016. The main outcome measure was the monetary value of training post characteristics, based on willingness to forgo additional potential income and willingness to accept extra income for a change in each job characteristic calculated from regression coefficients. 677/798 F2 doctors provided usable DCE responses. Location was the most influential characteristic of a training position, followed closely by supportive culture and then working conditions. F2 doctors would need to be compensated by an additional 45.75% above potential earnings to move from a post in a desirable location to one in an undesirable location. Doctors who applied for a training post placed less value on supportive culture and excellent working conditions than those who did not apply. Male F2s valued location and a supportive culture less than female F2s. This is the first study focusing on the career decision-making of UK doctors at a critical careers decision-making point. Both location and specific job-related attributes are highly valued by F2 doctors when deciding their future. This intelligence can inform workforce policy to focus their efforts in terms of making training posts attractive to this group of doctors to enhance recruitment and retention. © Article author

  10. What factors are critical to attracting NHS foundation doctors into specialty or core training? A discrete choice experiment

    PubMed Central

    Cleland, Jennifer; Johnston, Peter; Walker, Kim; Krucien, Nicolas; Skåtun, Diane

    2018-01-01

    Objectives Multiple personal and work-related factors influence medical trainees’ career decision-making. The relative value of these diverse factors is under-researched, yet this intelligence is crucially important for informing medical workforce planning and retention and recruitment policies. Our aim was to investigate the relative value of UK doctors’ preferences for different training post characteristics during the time period when they either apply for specialty or core training or take time out. Methods We developed a discrete choice experiment (DCE) specifically for this population. The DCE was distributed to all Foundation Programme Year 2 (F2) doctors across Scotland as part of the National Career Destination Survey in June 2016. The main outcome measure was the monetary value of training post characteristics, based on willingness to forgo additional potential income and willingness to accept extra income for a change in each job characteristic calculated from regression coefficients. Results 677/798 F2 doctors provided usable DCE responses. Location was the most influential characteristic of a training position, followed closely by supportive culture and then working conditions. F2 doctors would need to be compensated by an additional 45.75% above potential earnings to move from a post in a desirable location to one in an undesirable location. Doctors who applied for a training post placed less value on supportive culture and excellent working conditions than those who did not apply. Male F2s valued location and a supportive culture less than female F2s. Conclusion This is the first study focusing on the career decision-making of UK doctors at a critical careers decision-making point. Both location and specific job-related attributes are highly valued by F2 doctors when deciding their future. This intelligence can inform workforce policy to focus their efforts in terms of making training posts attractive to this group of doctors to enhance

  11. Characterization of high order spatial discretizations and lumping techniques for discontinuous finite element SN transport

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Maginot, P. G.; Ragusa, J. C.; Morel, J. E.

    2013-07-01

    We examine several possible methods of mass matrix lumping for discontinuous finite element discrete ordinates transport using a Lagrange interpolatory polynomial trial space. Though positive outflow angular flux is guaranteed with traditional mass matrix lumping in a purely absorbing 1-D slab cell for the linear discontinuous approximation, we show that when used with higher degree interpolatory polynomial trial spaces, traditional lumping does yield strictly positive outflows and does not increase in accuracy with an increase in trial space polynomial degree. As an alternative, we examine methods which are 'self-lumping'. Self-lumping methods yield diagonal mass matrices by using numerical quadrature restrictedmore » to the Lagrange interpolatory points. Using equally-spaced interpolatory points, self-lumping is achieved through the use of closed Newton-Cotes formulas, resulting in strictly positive outflows in pure absorbers for odd power polynomials in 1-D slab geometry. By changing interpolatory points from the traditional equally-spaced points to the quadrature points of the Gauss-Legendre or Lobatto-Gauss-Legendre quadratures, it is possible to generate solution representations with a diagonal mass matrix and a strictly positive outflow for any degree polynomial solution representation in a pure absorber medium in 1-D slab geometry. Further, there is no inherent limit to local truncation error order of accuracy when using interpolatory points that correspond to the quadrature points of high order accuracy numerical quadrature schemes. (authors)« less

  12. Alternative Reinforcer Response Cost Impacts Cocaine Choice in Humans

    PubMed Central

    Stoops, William W.; Lile, Joshua A.; Glaser, Paul E.A.; Hays, Lon R.; Rush, Craig R.

    2011-01-01

    Cocaine use disorders are an unrelenting public health concern. Behavioral treatments reduce cocaine use by providing non-drug alternative reinforcers. The purpose of this human laboratory experiment was to determine how response cost for non-drug alternative reinforcers influenced cocaine choice. Seven cocaine-using, non-treatment-seeking subjects completed a crossover, double-blind protocol in which they first sampled doses of intranasal cocaine (5, 10, 20 or 30 mg) and completed a battery of subject-rated and physiological measures. Subjects then made eight discrete choices between the sampled dose and an alternative reinforce (US$0.25). The response cost to earn a cocaine dose was always a fixed ratio (FR) of 100 responses. The response cost for the alternative reinforcer varied across sessions (FR1, FR10, FR100, FR1000). Dose-related increases were observed for cocaine choice. Subjects made fewer drug choices when the FR requirements for the alternative reinforcers were lower than that for drug relative to when the FR requirements were equal to or higher than that for drug. Intranasal cocaine also produced prototypical stimulant-like subject-rated and physiological effects (e.g., increased ratings of Like Drug; elevated blood pressure). These data demonstrate that making alternative reinforcers easier to earn reduces cocaine self-administration, which has implications for treatment efforts. PMID:22015480

  13. Quadratic Finite Element Method for 1D Deterministic Transport

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tolar, Jr., D R; Ferguson, J M

    2004-01-06

    In the discrete ordinates, or SN, numerical solution of the transport equation, both the spatial ({und r}) and angular ({und {Omega}}) dependences on the angular flux {psi}{und r},{und {Omega}}are modeled discretely. While significant effort has been devoted toward improving the spatial discretization of the angular flux, we focus on improving the angular discretization of {psi}{und r},{und {Omega}}. Specifically, we employ a Petrov-Galerkin quadratic finite element approximation for the differencing of the angular variable ({mu}) in developing the one-dimensional (1D) spherical geometry S{sub N} equations. We develop an algorithm that shows faster convergence with angular resolution than conventional S{sub N} algorithms.

  14. Serotonergic Genotypes, Neuroticism, and Financial Choices

    PubMed Central

    Kuhnen, Camelia M.; Samanez-Larkin, Gregory R.; Knutson, Brian

    2013-01-01

    Life financial outcomes carry a significant heritable component, but the mechanisms by which genes influence financial choices remain unclear. Focusing on a polymorphism in the promoter region of the serotonin transporter gene (5-HTTLPR), we found that individuals possessing the short allele of this gene invested less in equities, were less engaged in actively making investment decisions, and had fewer credit lines. Short allele carriers also showed higher levels of the personality trait neuroticism, despite not differing from others with respect to cognitive skills, education, or wealth. Mediation analysis suggested that the presence of the 5-HTTLPR short allele decreased real life measures of financial risk taking through its influence on neuroticism. These findings show that 5-HTTLPR short allele carriers avoid risky and complex financial choices due to negative emotional reactions, and have implications for understanding and managing individual differences in financial choice. PMID:23382929

  15. Serotonergic genotypes, neuroticism, and financial choices.

    PubMed

    Kuhnen, Camelia M; Samanez-Larkin, Gregory R; Knutson, Brian

    2013-01-01

    Life financial outcomes carry a significant heritable component, but the mechanisms by which genes influence financial choices remain unclear. Focusing on a polymorphism in the promoter region of the serotonin transporter gene (5-HTTLPR), we found that individuals possessing the short allele of this gene invested less in equities, were less engaged in actively making investment decisions, and had fewer credit lines. Short allele carriers also showed higher levels of the personality trait neuroticism, despite not differing from others with respect to cognitive skills, education, or wealth. Mediation analysis suggested that the presence of the 5-HTTLPR short allele decreased real life measures of financial risk taking through its influence on neuroticism. These findings show that 5-HTTLPR short allele carriers avoid risky and complex financial choices due to negative emotional reactions, and have implications for understanding and managing individual differences in financial choice.

  16. Discrete Regularization for Calibration of Geologic Facies Against Dynamic Flow Data

    NASA Astrophysics Data System (ADS)

    Khaninezhad, Mohammad-Reza; Golmohammadi, Azarang; Jafarpour, Behnam

    2018-04-01

    Subsurface flow model calibration involves many more unknowns than measurements, leading to ill-posed problems with nonunique solutions. To alleviate nonuniqueness, the problem is regularized by constraining the solution space using prior knowledge. In certain sedimentary environments, such as fluvial systems, the contrast in hydraulic properties of different facies types tends to dominate the flow and transport behavior, making the effect of within facies heterogeneity less significant. Hence, flow model calibration in those formations reduces to delineating the spatial structure and connectivity of different lithofacies types and their boundaries. A major difficulty in calibrating such models is honoring the discrete, or piecewise constant, nature of facies distribution. The problem becomes more challenging when complex spatial connectivity patterns with higher-order statistics are involved. This paper introduces a novel formulation for calibration of complex geologic facies by imposing appropriate constraints to recover plausible solutions that honor the spatial connectivity and discreteness of facies models. To incorporate prior connectivity patterns, plausible geologic features are learned from available training models. This is achieved by learning spatial patterns from training data, e.g., k-SVD sparse learning or the traditional Principal Component Analysis. Discrete regularization is introduced as a penalty functions to impose solution discreteness while minimizing the mismatch between observed and predicted data. An efficient gradient-based alternating directions algorithm is combined with variable splitting to minimize the resulting regularized nonlinear least squares objective function. Numerical results show that imposing learned facies connectivity and discreteness as regularization functions leads to geologically consistent solutions that improve facies calibration quality.

  17. A discrete mathematical model of the dynamic evolution of a transportation network

    NASA Astrophysics Data System (ADS)

    Malinetskii, G. G.; Stepantsov, M. E.

    2009-09-01

    A dynamic model of the evolution of a transportation network is proposed. The main feature of this model is that the evolution of the transportation network is not a process of centralized transportation optimization. Rather, its dynamic behavior is a result of the system self-organization that occurs in the course of the satisfaction of needs in goods transportation and the evolution of the infrastructure of the network nodes. Nonetheless, the possibility of soft control of the network evolution direction is taken into account.

  18. Comparison of generated parallel capillary arrays to three-dimensional reconstructed capillary networks in modeling oxygen transport in discrete microvascular volumes.

    PubMed

    Fraser, Graham M; Goldman, Daniel; Ellis, Christopher G

    2013-11-01

    We compare RMN to PCA under several simulated physiological conditions to determine how the use of different vascular geometry affects oxygen transport solutions. Three discrete networks were reconstructed from intravital video microscopy of rat skeletal muscle (84 × 168 × 342 μm, 70 × 157 × 268 μm, and 65 × 240 × 571 μm), and hemodynamic measurements were made in individual capillaries. PCAs were created based on statistical measurements from RMNs. Blood flow and O₂ transport models were applied, and the resulting solutions for RMN and PCA models were compared under four conditions (rest, exercise, ischemia, and hypoxia). Predicted tissue PO₂ was consistently lower in all RMN simulations compared to the paired PCA. PO₂ for 3D reconstructions at rest were 28.2 ± 4.8, 28.1 ± 3.5, and 33.0 ± 4.5 mmHg for networks I, II, and III compared to the PCA mean values of 31.2 ± 4.5, 30.6 ± 3.4, and 33.8 ± 4.6 mmHg. Simulated exercise yielded mean tissue PO₂ in the RMN of 10.1 ± 5.4, 12.6 ± 5.7, and 19.7 ± 5.7 mmHg compared to 15.3 ± 7.3, 18.8 ± 5.3, and 21.7 ± 6.0 in PCA. These findings suggest that volume matched PCA yield different results compared to reconstructed microvascular geometries when applied to O₂ transport modeling; the predominant characteristic of this difference being an over estimate of mean tissue PO₂. Despite this limitation, PCA models remain important for theoretical studies as they produce PO₂ distributions with similar shape and parameter dependence as RMN. © 2013 John Wiley & Sons Ltd.

  19. Space-Time Discrete KPZ Equation

    NASA Astrophysics Data System (ADS)

    Cannizzaro, G.; Matetski, K.

    2018-03-01

    We study a general family of space-time discretizations of the KPZ equation and show that they converge to its solution. The approach we follow makes use of basic elements of the theory of regularity structures (Hairer in Invent Math 198(2):269-504, 2014) as well as its discrete counterpart (Hairer and Matetski in Discretizations of rough stochastic PDEs, 2015. arXiv:1511.06937). Since the discretization is in both space and time and we allow non-standard discretization for the product, the methods mentioned above have to be suitably modified in order to accommodate the structure of the models under study.

  20. Mode Choice between Private and Public Transport in Klang Valley, Malaysia

    PubMed Central

    Karim, Mohamed Rehan; Yusoff, Sumiani

    2014-01-01

    In 2010, Klang Valley has only 17% trips each day were completed using public transport, with the rest of the 83% trips were made through private transport. The inclination towards private car usage will only get worse if the transport policy continues to be inefficient and ineffective. Under the National Key Economic Area, the priority aimed to stimulate the increase of modal share of public transport in the Klang Valley to 50% by 2020. In the 10th Malaysia Plan, the Klang Valley Mass Rapid Transit was proposed, equipped with 141 km of MRT system, and will integrate with the existing rail networks. Nevertheless, adding kilometers into the rail system will not help, if people do not make the shift from private into public transport. This research would like to assess the possible mode shift of travellers in the Klang Valley towards using public transport, based on the utility function of available transport modes. It intends to identify the criteria that will trigger their willingness to make changes in favour of public transport as targeted by the NKEA. PMID:24701165

  1. Solution of the within-group multidimensional discrete ordinates transport equations on massively parallel architectures

    NASA Astrophysics Data System (ADS)

    Zerr, Robert Joseph

    2011-12-01

    The integral transport matrix method (ITMM) has been used as the kernel of new parallel solution methods for the discrete ordinates approximation of the within-group neutron transport equation. The ITMM abandons the repetitive mesh sweeps of the traditional source iterations (SI) scheme in favor of constructing stored operators that account for the direct coupling factors among all the cells and between the cells and boundary surfaces. The main goals of this work were to develop the algorithms that construct these operators and employ them in the solution process, determine the most suitable way to parallelize the entire procedure, and evaluate the behavior and performance of the developed methods for increasing number of processes. This project compares the effectiveness of the ITMM with the SI scheme parallelized with the Koch-Baker-Alcouffe (KBA) method. The primary parallel solution method involves a decomposition of the domain into smaller spatial sub-domains, each with their own transport matrices, and coupled together via interface boundary angular fluxes. Each sub-domain has its own set of ITMM operators and represents an independent transport problem. Multiple iterative parallel solution methods have investigated, including parallel block Jacobi (PBJ), parallel red/black Gauss-Seidel (PGS), and parallel GMRES (PGMRES). The fastest observed parallel solution method, PGS, was used in a weak scaling comparison with the PARTISN code. Compared to the state-of-the-art SI-KBA with diffusion synthetic acceleration (DSA), this new method without acceleration/preconditioning is not competitive for any problem parameters considered. The best comparisons occur for problems that are difficult for SI DSA, namely highly scattering and optically thick. SI DSA execution time curves are generally steeper than the PGS ones. However, until further testing is performed it cannot be concluded that SI DSA does not outperform the ITMM with PGS even on several thousand or tens of

  2. Undesirable Choice Biases with Small Differences in the Spatial Structure of Chance Stimulus Sequences.

    PubMed

    Herrera, David; Treviño, Mario

    2015-01-01

    In two-alternative discrimination tasks, experimenters usually randomize the location of the rewarded stimulus so that systematic behavior with respect to irrelevant stimuli can only produce chance performance on the learning curves. One way to achieve this is to use random numbers derived from a discrete binomial distribution to create a 'full random training schedule' (FRS). When using FRS, however, sporadic but long laterally-biased training sequences occur by chance and such 'input biases' are thought to promote the generation of laterally-biased choices (i.e., 'output biases'). As an alternative, a 'Gellerman-like training schedule' (GLS) can be used. It removes most input biases by prohibiting the reward from appearing on the same location for more than three consecutive trials. The sequence of past rewards obtained from choosing a particular discriminative stimulus influences the probability of choosing that same stimulus on subsequent trials. Assuming that the long-term average ratio of choices matches the long-term average ratio of reinforcers, we hypothesized that a reduced amount of input biases in GLS compared to FRS should lead to a reduced production of output biases. We compared the choice patterns produced by a 'Rational Decision Maker' (RDM) in response to computer-generated FRS and GLS training sequences. To create a virtual RDM, we implemented an algorithm that generated choices based on past rewards. Our simulations revealed that, although the GLS presented fewer input biases than the FRS, the virtual RDM produced more output biases with GLS than with FRS under a variety of test conditions. Our results reveal that the statistical and temporal properties of training sequences interacted with the RDM to influence the production of output biases. Thus, discrete changes in the training paradigms did not translate linearly into modifications in the pattern of choices generated by a RDM. Virtual RDMs could be further employed to guide the selection of

  3. A practical method to test the validity of the standard Gumbel distribution in logit-based multinomial choice models of travel behavior

    DOE PAGES

    Ye, Xin; Garikapati, Venu M.; You, Daehyun; ...

    2017-11-08

    Most multinomial choice models (e.g., the multinomial logit model) adopted in practice assume an extreme-value Gumbel distribution for the random components (error terms) of utility functions. This distributional assumption offers a closed-form likelihood expression when the utility maximization principle is applied to model choice behaviors. As a result, model coefficients can be easily estimated using the standard maximum likelihood estimation method. However, maximum likelihood estimators are consistent and efficient only if distributional assumptions on the random error terms are valid. It is therefore critical to test the validity of underlying distributional assumptions on the error terms that form the basismore » of parameter estimation and policy evaluation. In this paper, a practical yet statistically rigorous method is proposed to test the validity of the distributional assumption on the random components of utility functions in both the multinomial logit (MNL) model and multiple discrete-continuous extreme value (MDCEV) model. Based on a semi-nonparametric approach, a closed-form likelihood function that nests the MNL or MDCEV model being tested is derived. The proposed method allows traditional likelihood ratio tests to be used to test violations of the standard Gumbel distribution assumption. Simulation experiments are conducted to demonstrate that the proposed test yields acceptable Type-I and Type-II error probabilities at commonly available sample sizes. The test is then applied to three real-world discrete and discrete-continuous choice models. For all three models, the proposed test rejects the validity of the standard Gumbel distribution in most utility functions, calling for the development of robust choice models that overcome adverse effects of violations of distributional assumptions on the error terms in random utility functions.« less

  4. A practical method to test the validity of the standard Gumbel distribution in logit-based multinomial choice models of travel behavior

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ye, Xin; Garikapati, Venu M.; You, Daehyun

    Most multinomial choice models (e.g., the multinomial logit model) adopted in practice assume an extreme-value Gumbel distribution for the random components (error terms) of utility functions. This distributional assumption offers a closed-form likelihood expression when the utility maximization principle is applied to model choice behaviors. As a result, model coefficients can be easily estimated using the standard maximum likelihood estimation method. However, maximum likelihood estimators are consistent and efficient only if distributional assumptions on the random error terms are valid. It is therefore critical to test the validity of underlying distributional assumptions on the error terms that form the basismore » of parameter estimation and policy evaluation. In this paper, a practical yet statistically rigorous method is proposed to test the validity of the distributional assumption on the random components of utility functions in both the multinomial logit (MNL) model and multiple discrete-continuous extreme value (MDCEV) model. Based on a semi-nonparametric approach, a closed-form likelihood function that nests the MNL or MDCEV model being tested is derived. The proposed method allows traditional likelihood ratio tests to be used to test violations of the standard Gumbel distribution assumption. Simulation experiments are conducted to demonstrate that the proposed test yields acceptable Type-I and Type-II error probabilities at commonly available sample sizes. The test is then applied to three real-world discrete and discrete-continuous choice models. For all three models, the proposed test rejects the validity of the standard Gumbel distribution in most utility functions, calling for the development of robust choice models that overcome adverse effects of violations of distributional assumptions on the error terms in random utility functions.« less

  5. Analysis of farmers' willingness to participate in pasture grazing programs: Results from a discrete choice experiment with German dairy farmers.

    PubMed

    Danne, M; Musshoff, O

    2017-09-01

    Over the last decades, the usage of pasture for grazing of dairy cows has decreased considerably. Pasture grazing programs initiated by dairy companies try to counteract this trend. The present paper investigates farmers' willingness to participate in such grazing programs. A special aim was to quantify the price premiums farmers require for program participation and to identify determinants influencing the premium level. The empirical analysis is based on a discrete choice experiment with 293 German dairy farmers. Models are estimated in terms of willingness to accept. It was found that farmers have no substantial preference for whether the pasture grazing program is financed by the food industry, a governmental scheme, or the dairy company. However, an extension of the annual or daily grazing period results in a decreasing willingness of farmers to participate in a pasture grazing program. In addition, farmers decline the option of a feeding standard prescribing the use of only green fodder when offered an alternative program that merely reduces the amount of concentrated feed or maize silage in the diet. Farmers' with an aversion toward program participation have a significant higher price demand for fulfilling the program requirements. Furthermore, the required price premiums increase with growing milk yields and a greater number of cows kept on the farm. However, if the availability of pasture is high, farmers are more likely to participate. The estimated price premiums and factors influencing farmers' willingness to participate found by this study should be considered by dairies and policymakers to gain insights into the design of possible pasture grazing programs from the perspective of farmers. Thereby, paying price premiums to farmers may increase the attractiveness of pasture grazing, which could finally result in an extended usage of pasture grazing. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  6. An exploration of parents' preferences for foot care in juvenile idiopathic arthritis: a possible role for the discrete choice experiment.

    PubMed

    Hendry, Gordon J; Turner, Debbie E; Gardner-Medwin, Janet; Lorgelly, Paula K; Woodburn, James

    2014-02-06

    An increased awareness of patients' and parents' care preferences regarding foot care is desirable from a clinical perspective as such information may be utilised to optimise care delivery. The aim of this study was to examine parents' preferences for, and valuations of foot care and foot-related outcomes in juvenile idiopathic arthritis (JIA). A discrete choice experiment (DCE) incorporating willingness-to-pay (WTP) questions was conducted by surveying 42 parents of children with JIA who were enrolled in a randomised-controlled trial of multidisciplinary foot care at a single UK paediatric rheumatology outpatients department. Attributes explored were: levels of pain; mobility; ability to perform activities of daily living (ADL); waiting time; referral route; and footwear. The DCE was administered at trial baseline. DCE data were analysed using a multinomial-logit-regression model to estimate preferences and relative importance of attributes of foot care. A stated-preference WTP question was presented to estimate parents' monetary valuation of health and service improvements. Every attribute in the DCE was statistically significant (p < 0.01) except that of cost (p = 0.118), suggesting that all attributes, except cost, have an impact on parents' preferences for foot care for their child. The magnitudes of the coefficients indicate that the strength of preference for each attribute was (in descending order): improved ability to perform ADL, reductions in foot pain, improved mobility, improved ability to wear desired footwear, multidisciplinary foot care route, and reduced waiting time. Parents' estimated mean annual WTP for a multidisciplinary foot care service was £1,119.05. In terms of foot care service provision for children with JIA, parents appear to prefer improvements in health outcomes over non-health outcomes and service process attributes. Cost was relatively less important than other attributes suggesting that it does not appear to impact on

  7. Mothers' Preferences and Willingness to Pay for Human Papillomavirus Vaccination for Their Daughters: A Discrete Choice Experiment in Hong Kong.

    PubMed

    Wong, Carlos K H; Man, Kenneth K C; Ip, Patrick; Kwan, Mike; McGhee, Sarah M

    2018-05-01

    To determine the preference of mothers in Hong Kong and their willingness to pay (WTP) for human papillomavirus (HPV) vaccination for their daughters. A discrete choice experiment survey with a two-alternative study design was developed. Data were collected from pediatric specialist outpatient clinics from 482 mothers with daughters aged between 8 and 17 years. Preferences of the four attributes of HPV vaccines (protection against cervical cancer, protection duration, side effects, and out-of-pocket costs) were evaluated. The marginal and overall WTP were estimated using multinomial logistic regression. A subgroup analysis was conducted to explore the impact of socioeconomic factors on mothers' WTP. Side effects, protection against cervical cancer, protection duration, and out-of-pocket cost determined the decision to receive or not receive the vaccine. All attributes had a statistically significant effect on the preference of and the WTP for the vaccine. Maximum WTP for ideal vaccines (i.e., 100% protection, lifetime protection duration, and 0% side effects) was HK$8976 (US $1129). The estimated WTP for vaccines currently available was HK$1620 (US $208), lower than the current market price. Among those who had a monthly household income of more than HK$100,000 (US $12,821), the WTP for vaccines currently offered was higher than the market price. This study provides new data on how features of the HPV vaccine are viewed and valued by mothers by determining their perception of ideal or improved and current vaccine technologies. These findings could contribute to future policies on the improvement of HPV vaccine and be useful for the immunization service in Hong Kong. Copyright © 2017 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  8. Comparing Analytic Hierarchy Process and Discrete-Choice Experiment to Elicit Patient Preferences for Treatment Characteristics in Age-Related Macular Degeneration.

    PubMed

    Danner, Marion; Vennedey, Vera; Hiligsmann, Mickaël; Fauser, Sascha; Gross, Christian; Stock, Stephanie

    2017-09-01

    In this study, we conducted an analytic hierarchy process (AHP) and a discrete choice experiment (DCE) to elicit the preferences of patients with age-related macular degeneration using identical attributes and levels. To compare preference-based weights for age-related macular degeneration treatment attributes and levels generated by two elicitation methods. The properties of both methods were assessed, including ease of instrument use. A DCE and an AHP experiment were designed on the basis of five attributes. Preference-based weights were generated using the matrix multiplication method for attributes and levels in AHP and a mixed multinomial logit model for levels in the DCE. Attribute importance was further compared using coefficient (DCE) and weight (AHP) level ranges. The questionnaire difficulty was rated on a qualitative scale. Patients were asked to think aloud while providing their judgments. AHP and DCE generated similar results regarding levels, stressing a preference for visual improvement, frequent monitoring, on-demand and less frequent injection schemes, approved drugs, and mild side effects. Attribute weights derived on the basis of level ranges led to a ranking that was opposite to the AHP directly calculated attribute weights. For example, visual function ranked first in the AHP and last on the basis of level ranges. The results across the methods were similar, with one exception: the directly measured AHP attribute weights were different from the level-based interpretation of attribute importance in both DCE and AHP. The dependence/independence of attribute importance on level ranges in DCE and AHP, respectively, should be taken into account when choosing a method to support decision making. Copyright © 2017 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  9. Assessment of the societal and individual preferences for fertility treatment in Australia: study protocol for stated preference discrete choice experiments

    PubMed Central

    Donnolley, Natasha; Shanahan, Marian; Chambers, Georgina M

    2018-01-01

    Introduction In Australia, societal and individual preferences for funding fertility treatment remain largely unknown. This has resulted in a lack of evidence about willingness to pay (WTP) for fertility treatment by either the general population (the funders) or infertile individuals (who directly benefit). Using a stated preference discrete choice experiment (SPDCE) approach has been suggested as a more appropriate method to inform economic evaluations of fertility treatment. We outline the protocol for an ongoing study which aims to assess fertility treatment preferences of both the general population and infertile individuals, and indirectly estimate their WTP for fertility treatment. Methods and analysis Two separate but related SPDCEs will be conducted for two population samples—the general population and infertile individuals—to elicit preferences for fertility treatment to indirectly estimate WTP. We describe the qualitative work to be undertaken to design the SPDCEs. We will use D-efficient fractional experimental designs informed by prior coefficients from the pilot surveys. The mode of administration for the SPDCE is also discussed. The final results will be analysed using mixed logit or latent class model. Ethics and dissemination This study is being funded by the Australian National Health and Medical Research Council (NHMRC) project grant AP1104543 and has been approved by the University of New South Wales Human Research Ethics Committee (HEC 17255) and a fertility clinic’s ethics committee. Findings of the study will be disseminated in peer-reviewed journals and presented at various conferences. A lay summary of the results will be made publicly available on the University of New South Wales National Perinatal Epidemiology and Statistics Unit website. Our results will contribute to the development of an evidence-based policy framework for the provision of cost-effective and patient-centred fertility treatment in Australia. PMID:29444788

  10. An exploration of parents’ preferences for foot care in juvenile idiopathic arthritis: a possible role for the discrete choice experiment

    PubMed Central

    2014-01-01

    Background An increased awareness of patients’ and parents’ care preferences regarding foot care is desirable from a clinical perspective as such information may be utilised to optimise care delivery. The aim of this study was to examine parents’ preferences for, and valuations of foot care and foot-related outcomes in juvenile idiopathic arthritis (JIA). Methods A discrete choice experiment (DCE) incorporating willingness-to-pay (WTP) questions was conducted by surveying 42 parents of children with JIA who were enrolled in a randomised-controlled trial of multidisciplinary foot care at a single UK paediatric rheumatology outpatients department. Attributes explored were: levels of pain; mobility; ability to perform activities of daily living (ADL); waiting time; referral route; and footwear. The DCE was administered at trial baseline. DCE data were analysed using a multinomial-logit-regression model to estimate preferences and relative importance of attributes of foot care. A stated-preference WTP question was presented to estimate parents’ monetary valuation of health and service improvements. Results Every attribute in the DCE was statistically significant (p < 0.01) except that of cost (p = 0.118), suggesting that all attributes, except cost, have an impact on parents’ preferences for foot care for their child. The magnitudes of the coefficients indicate that the strength of preference for each attribute was (in descending order): improved ability to perform ADL, reductions in foot pain, improved mobility, improved ability to wear desired footwear, multidisciplinary foot care route, and reduced waiting time. Parents’ estimated mean annual WTP for a multidisciplinary foot care service was £1,119.05. Conclusions In terms of foot care service provision for children with JIA, parents appear to prefer improvements in health outcomes over non-health outcomes and service process attributes. Cost was relatively less important than other attributes

  11. Northern Colorado Transportation Internship Program (NCTIP)

    DOT National Transportation Integrated Search

    2001-05-01

    The field of transportation is rapidly becoming a popular career choice for undergraduate engineering students. Many work opportunities are available in the area of transportation including computer software analysis, field testing, and consulting. U...

  12. SEAWAT-based simulation of axisymmetric heat transport.

    PubMed

    Vandenbohede, Alexander; Louwyck, Andy; Vlamynck, Nele

    2014-01-01

    Simulation of heat transport has its applications in geothermal exploitation of aquifers and the analysis of temperature dependent chemical reactions. Under homogeneous conditions and in the absence of a regional hydraulic gradient, groundwater flow and heat transport from or to a well exhibit radial symmetry, and governing equations are reduced by one dimension (1D) which increases computational efficiency importantly. Solute transport codes can simulate heat transport and input parameters may be modified such that the Cartesian geometry can handle radial flow. In this article, SEAWAT is evaluated as simulator for heat transport under radial flow conditions. The 1971, 1D analytical solution of Gelhar and Collins is used to compare axisymmetric transport with retardation (i.e., as a result of thermal equilibrium between fluid and solid) and a large diffusion (conduction). It is shown that an axisymmetric simulation compares well with a fully three dimensional (3D) simulation of an aquifer thermal energy storage systems. The influence of grid discretization, solver parameters, and advection solution is illustrated. Because of the high diffusion to simulate conduction, convergence criterion for heat transport must be set much smaller (10(-10) ) than for solute transport (10(-6) ). Grid discretization should be considered carefully, in particular the subdivision of the screen interval. On the other hand, different methods to calculate the pumping or injection rate distribution over different nodes of a multilayer well lead to small differences only. © 2013, National Ground Water Association.

  13. Efficient genetic algorithms using discretization scheduling.

    PubMed

    McLay, Laura A; Goldberg, David E

    2005-01-01

    In many applications of genetic algorithms, there is a tradeoff between speed and accuracy in fitness evaluations when evaluations use numerical methods with varying discretization. In these types of applications, the cost and accuracy vary from discretization errors when implicit or explicit quadrature is used to estimate the function evaluations. This paper examines discretization scheduling, or how to vary the discretization within the genetic algorithm in order to use the least amount of computation time for a solution of a desired quality. The effectiveness of discretization scheduling can be determined by comparing its computation time to the computation time of a GA using a constant discretization. There are three ingredients for the discretization scheduling: population sizing, estimated time for each function evaluation and predicted convergence time analysis. Idealized one- and two-dimensional experiments and an inverse groundwater application illustrate the computational savings to be achieved from using discretization scheduling.

  14. Do objective neighbourhood characteristics relate to residents' preferences for certain sports locations? A cross-sectional study using a discrete choice modelling approach.

    PubMed

    Deelen, Ineke; Jansen, Marijke; Dogterom, Nico J; Kamphuis, Carlijn B M; Ettema, Dick

    2017-12-11

    The number of sports facilities, sports clubs, or city parks in a residential neighbourhood may affect the likelihood that people participate in sports and their preferences for a certain sports location. This study aimed to assess whether objective physical and socio-spatial neighbourhood characteristics relate to sports participation and preferences for sports locations. Data from Dutch adults (N = 1201) on sports participation, their most-used sports location, and socio-demographic characteristics were collected using an online survey. Objective land-use data and the number of sports facilities were gathered for each participant using a 2000-m buffer around their home locations, whereas socio-spatial neighbourhood characteristics (i.e., density, socio-economic status, and safety) were determined at the neighbourhood level. A discrete choice-modelling framework (multinomial probit model) was used to model the associations between neighbourhood characteristics and sports participation and location. Higher proportions of green space, blue space, and the number of sports facilities were positively associated with sports participation in public space, at sports clubs, and at other sports facilities. Higher degrees of urbanization were negatively associated with sports participation at public spaces, sports clubs, and other sports facilities. Those with more green space, blue space or sports facilities in their residential neighbourhood were more likely to participate in sports, but these factors did not affect their preference for a certain sports location. Longitudinal study designs are necessary to assess causality: do active people choose to live in sports-facilitating neighbourhoods, or do neighbourhood characteristics affect sports participation?

  15. Distributed mean curvature on a discrete manifold for Regge calculus

    NASA Astrophysics Data System (ADS)

    Conboye, Rory; Miller, Warner A.; Ray, Shannon

    2015-09-01

    The integrated mean curvature of a simplicial manifold is well understood in both Regge Calculus and Discrete Differential Geometry. However, a well motivated pointwise definition of curvature requires a careful choice of the volume over which to uniformly distribute the local integrated curvature. We show that hybrid cells formed using both the simplicial lattice and its circumcentric dual emerge as a remarkably natural structure for the distribution of this local integrated curvature. These hybrid cells form a complete tessellation of the simplicial manifold, contain a geometric orthonormal basis, and are also shown to give a pointwise mean curvature with a natural interpretation as the fractional rate of change of the normal vector.

  16. A fast semi-discrete Kansa method to solve the two-dimensional spatiotemporal fractional diffusion equation

    NASA Astrophysics Data System (ADS)

    Sun, HongGuang; Liu, Xiaoting; Zhang, Yong; Pang, Guofei; Garrard, Rhiannon

    2017-09-01

    Fractional-order diffusion equations (FDEs) extend classical diffusion equations by quantifying anomalous diffusion frequently observed in heterogeneous media. Real-world diffusion can be multi-dimensional, requiring efficient numerical solvers that can handle long-term memory embedded in mass transport. To address this challenge, a semi-discrete Kansa method is developed to approximate the two-dimensional spatiotemporal FDE, where the Kansa approach first discretizes the FDE, then the Gauss-Jacobi quadrature rule solves the corresponding matrix, and finally the Mittag-Leffler function provides an analytical solution for the resultant time-fractional ordinary differential equation. Numerical experiments are then conducted to check how the accuracy and convergence rate of the numerical solution are affected by the distribution mode and number of spatial discretization nodes. Applications further show that the numerical method can efficiently solve two-dimensional spatiotemporal FDE models with either a continuous or discrete mixing measure. Hence this study provides an efficient and fast computational method for modeling super-diffusive, sub-diffusive, and mixed diffusive processes in large, two-dimensional domains with irregular shapes.

  17. Discrete Sparse Coding.

    PubMed

    Exarchakis, Georgios; Lücke, Jörg

    2017-11-01

    Sparse coding algorithms with continuous latent variables have been the subject of a large number of studies. However, discrete latent spaces for sparse coding have been largely ignored. In this work, we study sparse coding with latents described by discrete instead of continuous prior distributions. We consider the general case in which the latents (while being sparse) can take on any value of a finite set of possible values and in which we learn the prior probability of any value from data. This approach can be applied to any data generated by discrete causes, and it can be applied as an approximation of continuous causes. As the prior probabilities are learned, the approach then allows for estimating the prior shape without assuming specific functional forms. To efficiently train the parameters of our probabilistic generative model, we apply a truncated expectation-maximization approach (expectation truncation) that we modify to work with a general discrete prior. We evaluate the performance of the algorithm by applying it to a variety of tasks: (1) we use artificial data to verify that the algorithm can recover the generating parameters from a random initialization, (2) use image patches of natural images and discuss the role of the prior for the extraction of image components, (3) use extracellular recordings of neurons to present a novel method of analysis for spiking neurons that includes an intuitive discretization strategy, and (4) apply the algorithm on the task of encoding audio waveforms of human speech. The diverse set of numerical experiments presented in this letter suggests that discrete sparse coding algorithms can scale efficiently to work with realistic data sets and provide novel statistical quantities to describe the structure of the data.

  18. Trading off dietary choices, physical exercise and cardiovascular disease risks.

    PubMed

    Grisolía, José M; Longo, Alberto; Boeri, Marco; Hutchinson, George; Kee, Frank

    2013-09-01

    Despite several decades of decline, cardiovascular diseases are still the most common causes of death in Western societies. Sedentary living and high fat diets contribute to the prevalence of cardiovascular diseases. This paper analyses the trade-offs between lifestyle choices defined in terms of diet, physical activity, cost, and risk of cardiovascular disease that a representative sample of the population of Northern Ireland aged 40-65 are willing to make. Using computer assisted personal interviews, we survey 493 individuals at their homes using a Discrete Choice Experiment (DCE) questionnaire administered between February and July 2011 in Northern Ireland. Unlike most DCE studies for valuing public health programmes, this questionnaire uses a tailored exercise, based on the individuals' baseline choices. A "fat screener" module in the questionnaire links personal cardiovascular disease risk to each specific choice set in terms of dietary constituents. Individuals are informed about their real status quo risk of a fatal cardiovascular event, based on an initial set of health questions. Thus, actual risks, real diet and exercise choices are the elements that constitute the choice task. Our results show that our respondents are willing to pay for reducing mortality risk and, more importantly, are willing to change physical exercise and dietary behaviours. In particular, we find that to improve their lifestyles, overweight and obese people would be more likely to do more physical activity than to change their diets. Therefore, public policies aimed to target obesity and its related illnesses in Northern Ireland should invest public money in promoting physical activity rather than healthier diets. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Token reinforcement, choice, and self-control in pigeons.

    PubMed Central

    Jackson, K; Hackenberg, T D

    1996-01-01

    Pigeons were exposed to self-control procedures that involved illumination of light-emitting diodes (LEDs) as a form of token reinforcement. In a discrete-trials arrangement, subjects chose between one and three LEDs; each LED was exchangeable for 2-s access to food during distinct posttrial exchange periods. In Experiment 1, subjects generally preferred the immediate presentation of a single LED over the delayed presentation of three LEDs, but differences in the delay to the exchange period between the two options prevented a clear assessment of the relative influence of LED delay and exchange-period delay as determinants of choice. In Experiment 2, in which delays to the exchange period from either alternative were equal in most conditions, all subjects preferred the delayed three LEDs more often than in Experiment-1. In Experiment 3, subjects preferred the option that resulted in a greater amount of food more often if the choices also produced LEDs than if they did not. In Experiment 4, preference for the delayed three LEDs was obtained when delays to the exchange period were equal, but reversed in favor of an immediate single LED when the latter choice also resulted in quicker access to exchange periods. The overall pattern of results suggests that (a) delay to the exchange period is a more critical determinant of choice than is delay to token presentation; (b) tokens may function as conditioned reinforcers, although their discriminative properties may be responsible for the self-control that occurs under token reinforcer arrangements; and (c) previously reported differences in the self-control choices of humans and pigeons may have resulted at least in part from the procedural conventions of using token reinforcers with human subjects and food reinforcers with pigeon subjects. PMID:8755699

  20. Motivational State and Reward Content Determine Choice Behavior under Risk in Mice

    PubMed Central

    Leblond, Mona; Fan, David; Brynildsen, Julia K.; Yin, Henry H.

    2011-01-01

    Risk is a ubiquitous feature of the environment for most organisms, who must often choose between a small and certain reward and a larger but less certain reward. To study choice behavior under risk in a genetically well characterized species, we trained mice (C57BL/6) on a discrete trial, concurrent-choice task in which they must choose between two levers. Pressing one lever (safe choice) is always followed by a small reward. Pressing the other lever (risky choice) is followed by a larger reward, but only on some of the trials. The overall payoff is the same on both levers. When mice were not food deprived, they were indifferent to risk, choosing both levers with equal probability regardless of the level of risk. In contrast, following food or water deprivation, mice earning 10% sucrose solution were risk-averse, though the addition of alcohol to the sucrose solution dose-dependently reduced risk aversion, even before the mice became intoxicated. Our results falsify the budget rule in optimal foraging theory often used to explain behavior under risk. Instead, they suggest that the overall demand or desired amount for a particular reward determines risk preference. Changes in motivational state or reward identity affect risk preference by changing demand. Any manipulation that increases the demand for a reward also increases risk aversion, by selectively increasing the frequency of safe choices without affecting frequency of risky choices. PMID:21966504

  1. Motivational state and reward content determine choice behavior under risk in mice.

    PubMed

    Leblond, Mona; Fan, David; Brynildsen, Julia K; Yin, Henry H

    2011-01-01

    Risk is a ubiquitous feature of the environment for most organisms, who must often choose between a small and certain reward and a larger but less certain reward. To study choice behavior under risk in a genetically well characterized species, we trained mice (C57BL/6) on a discrete trial, concurrent-choice task in which they must choose between two levers. Pressing one lever (safe choice) is always followed by a small reward. Pressing the other lever (risky choice) is followed by a larger reward, but only on some of the trials. The overall payoff is the same on both levers. When mice were not food deprived, they were indifferent to risk, choosing both levers with equal probability regardless of the level of risk. In contrast, following food or water deprivation, mice earning 10% sucrose solution were risk-averse, though the addition of alcohol to the sucrose solution dose-dependently reduced risk aversion, even before the mice became intoxicated. Our results falsify the budget rule in optimal foraging theory often used to explain behavior under risk. Instead, they suggest that the overall demand or desired amount for a particular reward determines risk preference. Changes in motivational state or reward identity affect risk preference by changing demand. Any manipulation that increases the demand for a reward also increases risk aversion, by selectively increasing the frequency of safe choices without affecting frequency of risky choices.

  2. Discrete breathers for a discrete nonlinear Schrödinger ring coupled to a central site.

    PubMed

    Jason, Peter; Johansson, Magnus

    2016-01-01

    We examine the existence and properties of certain discrete breathers for a discrete nonlinear Schrödinger model where all but one site are placed in a ring and coupled to the additional central site. The discrete breathers we focus on are stationary solutions mainly localized on one or a few of the ring sites and possibly also the central site. By numerical methods, we trace out and study the continuous families the discrete breathers belong to. Our main result is the discovery of a split bifurcation at a critical value of the coupling between neighboring ring sites. Below this critical value, families form closed loops in a certain parameter space, implying that discrete breathers with and without central-site occupation belong to the same family. Above the split bifurcation the families split up into several separate ones, which bifurcate with solutions with constant ring amplitudes. For symmetry reasons, the families have different properties below the split bifurcation for even and odd numbers of sites. It is also determined under which conditions the discrete breathers are linearly stable. The dynamics of some simpler initial conditions that approximate the discrete breathers are also studied and the parameter regimes where the dynamics remain localized close to the initially excited ring site are related to the linear stability of the exact discrete breathers.

  3. 3-D discrete analytical ridgelet transform.

    PubMed

    Helbert, David; Carré, Philippe; Andres, Eric

    2006-12-01

    In this paper, we propose an implementation of the 3-D Ridgelet transform: the 3-D discrete analytical Ridgelet transform (3-D DART). This transform uses the Fourier strategy for the computation of the associated 3-D discrete Radon transform. The innovative step is the definition of a discrete 3-D transform with the discrete analytical geometry theory by the construction of 3-D discrete analytical lines in the Fourier domain. We propose two types of 3-D discrete lines: 3-D discrete radial lines going through the origin defined from their orthogonal projections and 3-D planes covered with 2-D discrete line segments. These discrete analytical lines have a parameter called arithmetical thickness, allowing us to define a 3-D DART adapted to a specific application. Indeed, the 3-D DART representation is not orthogonal, It is associated with a flexible redundancy factor. The 3-D DART has a very simple forward/inverse algorithm that provides an exact reconstruction without any iterative method. In order to illustrate the potentiality of this new discrete transform, we apply the 3-D DART and its extension to the Local-DART (with smooth windowing) to the denoising of 3-D image and color video. These experimental results show that the simple thresholding of the 3-D DART coefficients is efficient.

  4. Fracture size and transmissivity correlations: Implications for transport simulations in sparse three-dimensional discrete fracture networks following a truncated power law distribution of fracture size

    NASA Astrophysics Data System (ADS)

    Hyman, J. D.; Aldrich, G.; Viswanathan, H.; Makedonska, N.; Karra, S.

    2016-08-01

    We characterize how different fracture size-transmissivity relationships influence flow and transport simulations through sparse three-dimensional discrete fracture networks. Although it is generally accepted that there is a positive correlation between a fracture's size and its transmissivity/aperture, the functional form of that relationship remains a matter of debate. Relationships that assume perfect correlation, semicorrelation, and noncorrelation between the two have been proposed. To study the impact that adopting one of these relationships has on transport properties, we generate multiple sparse fracture networks composed of circular fractures whose radii follow a truncated power law distribution. The distribution of transmissivities are selected so that the mean transmissivity of the fracture networks are the same and the distributions of aperture and transmissivity in models that include a stochastic term are also the same. We observe that adopting a correlation between a fracture size and its transmissivity leads to earlier breakthrough times and higher effective permeability when compared to networks where no correlation is used. While fracture network geometry plays the principal role in determining where transport occurs within the network, the relationship between size and transmissivity controls the flow speed. These observations indicate DFN modelers should be aware that breakthrough times and effective permeabilities can be strongly influenced by such a relationship in addition to fracture and network statistics.

  5. Fracture size and transmissivity correlations: Implications for transport simulations in sparse three-dimensional discrete fracture networks following a truncated power law distribution of fracture size

    NASA Astrophysics Data System (ADS)

    Hyman, J.; Aldrich, G. A.; Viswanathan, H. S.; Makedonska, N.; Karra, S.

    2016-12-01

    We characterize how different fracture size-transmissivity relationships influence flow and transport simulations through sparse three-dimensional discrete fracture networks. Although it is generally accepted that there is a positive correlation between a fracture's size and its transmissivity/aperture, the functional form of that relationship remains a matter of debate. Relationships that assume perfect correlation, semi-correlation, and non-correlation between the two have been proposed. To study the impact that adopting one of these relationships has on transport properties, we generate multiple sparse fracture networks composed of circular fractures whose radii follow a truncated power law distribution. The distribution of transmissivities are selected so that the mean transmissivity of the fracture networks are the same and the distributions of aperture and transmissivity in models that include a stochastic term are also the same.We observe that adopting a correlation between a fracture size and its transmissivity leads to earlier breakthrough times and higher effective permeability when compared to networks where no correlation is used. While fracture network geometry plays the principal role in determining where transport occurs within the network, the relationship between size and transmissivity controls the flow speed. These observations indicate DFN modelers should be aware that breakthrough times and effective permeabilities can be strongly influenced by such a relationship in addition to fracture and network statistics.

  6. Fracture size and transmissivity correlations: Implications for transport simulations in sparse three-dimensional discrete fracture networks following a truncated power law distribution of fracture size

    DOE PAGES

    Hyman, Jeffrey De'Haven; Aldrich, Garrett Allen; Viswanathan, Hari S.; ...

    2016-08-01

    We characterize how different fracture size-transmissivity relationships influence flow and transport simulations through sparse three-dimensional discrete fracture networks. Although it is generally accepted that there is a positive correlation between a fracture's size and its transmissivity/aperture, the functional form of that relationship remains a matter of debate. Relationships that assume perfect correlation, semicorrelation, and noncorrelation between the two have been proposed. To study the impact that adopting one of these relationships has on transport properties, we generate multiple sparse fracture networks composed of circular fractures whose radii follow a truncated power law distribution. The distribution of transmissivities are selected somore » that the mean transmissivity of the fracture networks are the same and the distributions of aperture and transmissivity in models that include a stochastic term are also the same. We observe that adopting a correlation between a fracture size and its transmissivity leads to earlier breakthrough times and higher effective permeability when compared to networks where no correlation is used. While fracture network geometry plays the principal role in determining where transport occurs within the network, the relationship between size and transmissivity controls the flow speed. Lastly, these observations indicate DFN modelers should be aware that breakthrough times and effective permeabilities can be strongly influenced by such a relationship in addition to fracture and network statistics.« less

  7. Fracture size and transmissivity correlations: Implications for transport simulations in sparse three-dimensional discrete fracture networks following a truncated power law distribution of fracture size

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hyman, Jeffrey De'Haven; Aldrich, Garrett Allen; Viswanathan, Hari S.

    We characterize how different fracture size-transmissivity relationships influence flow and transport simulations through sparse three-dimensional discrete fracture networks. Although it is generally accepted that there is a positive correlation between a fracture's size and its transmissivity/aperture, the functional form of that relationship remains a matter of debate. Relationships that assume perfect correlation, semicorrelation, and noncorrelation between the two have been proposed. To study the impact that adopting one of these relationships has on transport properties, we generate multiple sparse fracture networks composed of circular fractures whose radii follow a truncated power law distribution. The distribution of transmissivities are selected somore » that the mean transmissivity of the fracture networks are the same and the distributions of aperture and transmissivity in models that include a stochastic term are also the same. We observe that adopting a correlation between a fracture size and its transmissivity leads to earlier breakthrough times and higher effective permeability when compared to networks where no correlation is used. While fracture network geometry plays the principal role in determining where transport occurs within the network, the relationship between size and transmissivity controls the flow speed. Lastly, these observations indicate DFN modelers should be aware that breakthrough times and effective permeabilities can be strongly influenced by such a relationship in addition to fracture and network statistics.« less

  8. Valuing improved wetland quality using choice modeling

    NASA Astrophysics Data System (ADS)

    Morrison, Mark; Bennett, Jeff; Blamey, Russell

    1999-09-01

    The main stated preference technique used for estimating environmental values is the contingent valuation method. In this paper the results of an application of an alternative technique, choice modeling, are reported. Choice modeling has been developed in the marketing and transport applications but has only been used in a handful of environmental applications, most of which have focused on use values. The case study presented here involves the estimation of the nonuse environmental values provided by the Macquarie Marshes, a major wetland in New South Wales, Australia. Estimates of the nonuse value the community places on preventing job losses are also presented. The reported models are robust, having high explanatory power and variables that are statistically significant and consistent with expectations. These results provide support for the hypothesis that choice modeling can be used to estimate nonuse values for both environmental and social consequences of resource use changes.

  9. Genomic testing to determine drug response: measuring preferences of the public and patients using Discrete Choice Experiment (DCE)

    PubMed Central

    2013-01-01

    Background The extent to which a genomic test will be used in practice is affected by factors such as ability of the test to correctly predict response to treatment (i.e. sensitivity and specificity of the test), invasiveness of the testing procedure, test cost, and the probability and severity of side effects associated with treatment. Methods Using discrete choice experimentation (DCE), we elicited preferences of the public (Sample 1, N = 533 and Sample 2, N = 525) and cancer patients (Sample 3, N = 38) for different attributes of a hypothetical genomic test for guiding cancer treatment. Samples 1 and 3 considered the test/treatment in the context of an aggressive curable cancer (scenario A) while the scenario for sample 2 was based on a non-aggressive incurable cancer (scenario B). Results In aggressive curable cancer (scenario A), everything else being equal, the odds ratio (OR) of choosing a test with 95% sensitivity was 1.41 (versus a test with 50% sensitivity) and willingness to pay (WTP) was $1331, on average, for this amount of improvement in test sensitivity. In this scenario, the OR of choosing a test with 95% specificity was 1.24 times that of a test with 50% specificity (WTP = $827). In non-aggressive incurable cancer (scenario B), the OR of choosing a test with 95% sensitivity was 1.65 (WTP = $1344), and the OR of choosing a test with 95% specificity was 1.50 (WTP = $1080). Reducing severity of treatment side effects from severe to mild was associated with large ORs in both scenarios (OR = 2.10 and 2.24 in scenario A and B, respectively). In contrast, patients had a very large preference for 95% sensitivity of the test (OR = 5.23). Conclusion The type and prognosis of cancer affected preferences for genomically-guided treatment. In aggressive curable cancer, individuals emphasized more on the sensitivity rather than the specificity of the test. In contrast, for a non-aggressive incurable cancer, individuals put similar

  10. Adaptive Discrete Hypergraph Matching.

    PubMed

    Yan, Junchi; Li, Changsheng; Li, Yin; Cao, Guitao

    2018-02-01

    This paper addresses the problem of hypergraph matching using higher-order affinity information. We propose a solver that iteratively updates the solution in the discrete domain by linear assignment approximation. The proposed method is guaranteed to converge to a stationary discrete solution and avoids the annealing procedure and ad-hoc post binarization step that are required in several previous methods. Specifically, we start with a simple iterative discrete gradient assignment solver. This solver can be trapped in an -circle sequence under moderate conditions, where is the order of the graph matching problem. We then devise an adaptive relaxation mechanism to jump out this degenerating case and show that the resulting new path will converge to a fixed solution in the discrete domain. The proposed method is tested on both synthetic and real-world benchmarks. The experimental results corroborate the efficacy of our method.

  11. Impact of Stress on Anomalous Transport in Fractured Rock

    NASA Astrophysics Data System (ADS)

    Kang, P. K.; Lei, Q.; Lee, S.; Dentz, M.; Juanes, R.

    2016-12-01

    Fluid flow and transport in fractured rock controls many natural and engineered processes in the subsurface. However, characterizing flow and transport through fractured media is challenging due to the large heterogeneity of fractured rock properties. In addition to these "static" challenges, geologic fractures are always under significant overburden stress, and changes in the stress state can lead to changes in the fracture's ability to conduct fluids. While confining stress has been shown to impact fluid flow through fractures in a fundamental way, the impact of confining stress on transport through fractured rock remains largely unexplored. The link between anomalous (non-Fickian) transport and confining stress has been shown only recently, at the level of a single rough fracture [1]. Here, we investigate the impact of confining stress on flow and transport through discrete fracture networks. We model geomechanical effects in 2D fractured rock by means of a finite-discrete element method (FEMDEM), which can capture the deformation of matrix blocks, reactivation and propagation of cracks. We implement a joint constitutive model within the FEMDEM framework to simulate the effect of fracture roughness. We apply the model to a fracture network extracted from the geological map of an actual outcrop to obtain the aperture field at different stress conditions (Figure 1). We then simulate fluid flow and particle transport through the stressed fracture networks. We observe that anomalous transport emerges in response to confining stress on the fracture networks, and show that this anomalous behavior can be linked to the stress state of the rock. Finally, we develop an effective transport model that captures the anomalous transport through stressed fractures. Our results point to a heretofore unrecognized link between geomechanics and anomalous transport in discrete fractured networks. [1] P. K. Kang, S. Brown, and R. Juanes, Emergence of anomalous transport in stressed

  12. An analysis of numerical convergence in discrete velocity gas dynamics for internal flows

    NASA Astrophysics Data System (ADS)

    Sekaran, Aarthi; Varghese, Philip; Goldstein, David

    2018-07-01

    The Discrete Velocity Method (DVM) for solving the Boltzmann equation has significant advantages in the modeling of non-equilibrium and near equilibrium flows as compared to other methods in terms of reduced statistical noise, faster solutions and the ability to handle transient flows. Yet the DVM performance for rarefied flow in complex, small-scale geometries, in microelectromechanical (MEMS) devices for instance, is yet to be studied in detail. The present study focuses on the performance of the DVM for locally large Knudsen number flows of argon around sharp corners and other sources for discontinuities in the distribution function. Our analysis details the nature of the solution for some benchmark cases and introduces the concept of solution convergence for the transport terms in the discrete velocity Boltzmann equation. The limiting effects of the velocity space discretization are also investigated and the constraints on obtaining a robust, consistent solution are derived. We propose techniques to maintain solution convergence and demonstrate the implementation of a specific strategy and its effect on the fidelity of the solution for some benchmark cases.

  13. Societal Preferences for Funding Orphan Drugs in the United Kingdom: An Application of Person Trade-Off and Discrete Choice Experiment Methods.

    PubMed

    Bourke, Siobhan M; Plumpton, Catrin O; Hughes, Dyfrig A

    2018-05-01

    It is unclear whether UK National Health Service (NHS) policies for orphan drugs, which permit funding of non-cost-effective treatments, reflect societal preferences. We conducted person trade-off (PTO) and discrete choice experiment (DCE) among 3950 adults selected to be representative of the UK general population. Experimental design was informed by surveys of patients affected by rare diseases, their caregivers, health care staff, and policymakers. Societal preferences were estimated in relation to treating a common disease, increases in waiting lists, or filling of vacant NHS posts. Results of the DCE were applied to recently licensed orphan drugs. On the basis of equal cost, the majority of respondents to the PTO (54%; 95% confidence interval [CI] 50-59) chose to allocate funds equally between patients treated for rare diseases and those treated for common diseases, with 32% (95% CI 28-36) favoring treating rare diseases over treating common diseases (14%; 95% CI 11-17), which this reduced to 23% (95% CI 20-27) when rare disease treatments were 10 times more expensive. When framed differently, more respondents prioritized not increasing waiting list size (43%; 95% CI 39-48) than to treat rare disease patients (34%; 95% CI 30-38). The DCE indicated a greater preference for treating a common disease over a rare disease. Respondents agreed with five of 12 positive appraisal recommendations for orphan drugs, even if their list price was higher, but preferred the NHS not to fund the remainder. The general public does not value rarity as a sufficient reason to justify special consideration for additional NHS funding of orphan drugs. This has implications regarding the appropriateness of operating higher thresholds of cost-effectiveness. Copyright © 2018 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  14. Identifying Societal Preferences for River Restoration in a Densely Populated Urban Environment: Evidence from a Discrete Choice Experiment in Central Brussels

    NASA Astrophysics Data System (ADS)

    Chen, Wendy Y.; Liekens, Inge; Broekx, Steven

    2017-08-01

    One of the major challenges facing river restoration in densely populated urban areas has been the disparity between the expectations of policy-makers and societal preferences. This study aimed to elicit public preferences and elucidate underlying sources of preference heterogeneity, using the Zenne River in central Brussels, Belgium, as a case study. A discrete choice experiment was administered to a representative sample of the Brussels population. Five attributes were specified, including water quality, ecological status, hydromorphological features of channels, recreational opportunities, and monetary cost. Our econometric analysis based on mixed logit models revealed that overall public would like to have a more natural river (open and naturalized channel, good water quality, and with rich species diversity), while achieving good water quality was the most preferred attribute. Respondents categorized as male, non-Belgian citizen, or not being a member of an environmental organization constituted an inclination to prefer the status quo. Belgian citizens showed a pronounced preference for good biodiversity, and being a member of an environmental organization could moderate the strong preference for good water quality. This study provided insights into the relative attractiveness of key attributes pertaining to river restoration, in general, and served as a useful input to the ongoing discussion concerning the future plan for the Zenne River in Brussels, specifically. Possible implications also exist for other urban river restorations in the rest of Europe, where the Water Framework Directive has become a major impetus for the expansion of freshwater ecosystem restoration from rural and peri-urban areas to densely populated urban areas. Particularly, the cultural heterogeneity of societal preferences should be tested and accounted for to compare the welfare impacts of river restoration and to facilitate benefit transfer, within and between river basins, in the

  15. Identifying Societal Preferences for River Restoration in a Densely Populated Urban Environment: Evidence from a Discrete Choice Experiment in Central Brussels.

    PubMed

    Chen, Wendy Y; Liekens, Inge; Broekx, Steven

    2017-08-01

    One of the major challenges facing river restoration in densely populated urban areas has been the disparity between the expectations of policy-makers and societal preferences. This study aimed to elicit public preferences and elucidate underlying sources of preference heterogeneity, using the Zenne River in central Brussels, Belgium, as a case study. A discrete choice experiment was administered to a representative sample of the Brussels population. Five attributes were specified, including water quality, ecological status, hydromorphological features of channels, recreational opportunities, and monetary cost. Our econometric analysis based on mixed logit models revealed that overall public would like to have a more natural river (open and naturalized channel, good water quality, and with rich species diversity), while achieving good water quality was the most preferred attribute. Respondents categorized as male, non-Belgian citizen, or not being a member of an environmental organization constituted an inclination to prefer the status quo. Belgian citizens showed a pronounced preference for good biodiversity, and being a member of an environmental organization could moderate the strong preference for good water quality. This study provided insights into the relative attractiveness of key attributes pertaining to river restoration, in general, and served as a useful input to the ongoing discussion concerning the future plan for the Zenne River in Brussels, specifically. Possible implications also exist for other urban river restorations in the rest of Europe, where the Water Framework Directive has become a major impetus for the expansion of freshwater ecosystem restoration from rural and peri-urban areas to densely populated urban areas. Particularly, the cultural heterogeneity of societal preferences should be tested and accounted for to compare the welfare impacts of river restoration and to facilitate benefit transfer, within and between river basins, in the

  16. Multiscale Simulations of Reactive Transport

    NASA Astrophysics Data System (ADS)

    Tartakovsky, D. M.; Bakarji, J.

    2014-12-01

    Discrete, particle-based simulations offer distinct advantages when modeling solute transport and chemical reactions. For example, Brownian motion is often used to model diffusion in complex pore networks, and Gillespie-type algorithms allow one to handle multicomponent chemical reactions with uncertain reaction pathways. Yet such models can be computationally more intensive than their continuum-scale counterparts, e.g., advection-dispersion-reaction equations. Combining the discrete and continuum models has a potential to resolve the quantity of interest with a required degree of physicochemical granularity at acceptable computational cost. We present computational examples of such "hybrid models" and discuss the challenges associated with coupling these two levels of description.

  17. Genetic Algorithms for Multiple-Choice Problems

    NASA Astrophysics Data System (ADS)

    Aickelin, Uwe

    2010-04-01

    This thesis investigates the use of problem-specific knowledge to enhance a genetic algorithm approach to multiple-choice optimisation problems.It shows that such information can significantly enhance performance, but that the choice of information and the way it is included are important factors for success.Two multiple-choice problems are considered.The first is constructing a feasible nurse roster that considers as many requests as possible.In the second problem, shops are allocated to locations in a mall subject to constraints and maximising the overall income.Genetic algorithms are chosen for their well-known robustness and ability to solve large and complex discrete optimisation problems.However, a survey of the literature reveals room for further research into generic ways to include constraints into a genetic algorithm framework.Hence, the main theme of this work is to balance feasibility and cost of solutions.In particular, co-operative co-evolution with hierarchical sub-populations, problem structure exploiting repair schemes and indirect genetic algorithms with self-adjusting decoder functions are identified as promising approaches.The research starts by applying standard genetic algorithms to the problems and explaining the failure of such approaches due to epistasis.To overcome this, problem-specific information is added in a variety of ways, some of which are designed to increase the number of feasible solutions found whilst others are intended to improve the quality of such solutions.As well as a theoretical discussion as to the underlying reasons for using each operator,extensive computational experiments are carried out on a variety of data.These show that the indirect approach relies less on problem structure and hence is easier to implement and superior in solution quality.

  18. Coupled discrete element and finite volume solution of two classical soil mechanics problems

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chen, Feng; Drumm, Eric; Guiochon, Georges A

    One dimensional solutions for the classic critical upward seepage gradient/quick condition and the time rate of consolidation problems are obtained using coupled routines for the finite volume method (FVM) and discrete element method (DEM), and the results compared with the analytical solutions. The two phase flow in a system composed of fluid and solid is simulated with the fluid phase modeled by solving the averaged Navier-Stokes equation using the FVM and the solid phase is modeled using the DEM. A framework is described for the coupling of two open source computer codes: YADE-OpenDEM for the discrete element method and OpenFOAMmore » for the computational fluid dynamics. The particle-fluid interaction is quantified using a semi-empirical relationship proposed by Ergun [12]. The two classical verification problems are used to explore issues encountered when using coupled flow DEM codes, namely, the appropriate time step size for both the fluid and mechanical solution processes, the choice of the viscous damping coefficient, and the number of solid particles per finite fluid volume.« less

  19. State Regulators Promote Consumer Choice in Retail Gas Markets

    EIA Publications

    1996-01-01

    Restructuring of interstate pipeline companies has created new choices and challenges for local distribution companies (LDCs), their regulators, and their customers. The process of separating interstate pipeline gas sales from transportation service has been completed and has resulted in greater gas procurement options for LDCs.

  20. Discrete Jordan curve theorem

    NASA Astrophysics Data System (ADS)

    Chen, Li

    1999-09-01

    According to a general definition of discrete curves, surfaces, and manifolds (Li Chen, 'Generalized discrete object tracking algorithms and implementations, ' In Melter, Wu, and Latecki ed, Vision Geometry VI, SPIE Vol. 3168, pp 184 - 195, 1997.). This paper focuses on the Jordan curve theorem in 2D discrete spaces. The Jordan curve theorem says that a (simply) closed curve separates a simply connected surface into two components. Based on the definition of discrete surfaces, we give three reasonable definitions of simply connected spaces. Theoretically, these three definition shall be equivalent. We have proved the Jordan curve theorem under the third definition of simply connected spaces. The Jordan theorem shows the relationship among an object, its boundary, and its outside area. In continuous space, the boundary of an mD manifold is an (m - 1)D manifold. The similar result does apply to regular discrete manifolds. The concept of a new regular nD-cell is developed based on the regular surface point in 2D, and well-composed objects in 2D and 3D given by Latecki (L. Latecki, '3D well-composed pictures,' In Melter, Wu, and Latecki ed, Vision Geometry IV, SPIE Vol 2573, pp 196 - 203, 1995.).