Building an Evaluation Scale using Item Response Theory.

PubMed

Lalor, John P; Wu, Hao; Yu, Hong

2016-11-01

Evaluation of NLP methods requires testing against a previously vetted gold-standard test set and reporting standard metrics (accuracy/precision/recall/F1). The current assumption is that all items in a given test set are equal with regards to difficulty and discriminating power. We propose Item Response Theory (IRT) from psychometrics as an alternative means for gold-standard test-set generation and NLP system evaluation. IRT is able to describe characteristics of individual items - their difficulty and discriminating power - and can account for these characteristics in its estimation of human intelligence or ability for an NLP task. In this paper, we demonstrate IRT by generating a gold-standard test set for Recognizing Textual Entailment. By collecting a large number of human responses and fitting our IRT model, we show that our IRT model compares NLP systems with the performance in a human population and is able to provide more insight into system performance than standard evaluation metrics. We show that a high accuracy score does not always imply a high IRT score, which depends on the item characteristics and the response pattern.

Building an Evaluation Scale using Item Response Theory

PubMed Central

Lalor, John P.; Wu, Hao; Yu, Hong

2016-01-01

Evaluation of NLP methods requires testing against a previously vetted gold-standard test set and reporting standard metrics (accuracy/precision/recall/F1). The current assumption is that all items in a given test set are equal with regards to difficulty and discriminating power. We propose Item Response Theory (IRT) from psychometrics as an alternative means for gold-standard test-set generation and NLP system evaluation. IRT is able to describe characteristics of individual items - their difficulty and discriminating power - and can account for these characteristics in its estimation of human intelligence or ability for an NLP task. In this paper, we demonstrate IRT by generating a gold-standard test set for Recognizing Textual Entailment. By collecting a large number of human responses and fitting our IRT model, we show that our IRT model compares NLP systems with the performance in a human population and is able to provide more insight into system performance than standard evaluation metrics. We show that a high accuracy score does not always imply a high IRT score, which depends on the item characteristics and the response pattern.1 PMID:28004039

The value of item response theory in clinical assessment: a review.

PubMed

Thomas, Michael L

2011-09-01

Item response theory (IRT) and related latent variable models represent modern psychometric theory, the successor to classical test theory in psychological assessment. Although IRT has become prevalent in the measurement of ability and achievement, its contributions to clinical domains have been less extensive. Applications of IRT to clinical assessment are reviewed to appraise its current and potential value. Benefits of IRT include comprehensive analyses and reduction of measurement error, creation of computer adaptive tests, meaningful scaling of latent variables, objective calibration and equating, evaluation of test and item bias, greater accuracy in the assessment of change due to therapeutic intervention, and evaluation of model and person fit. The theory may soon reinvent the manner in which tests are selected, developed, and scored. Although challenges remain to the widespread implementation of IRT, its application to clinical assessment holds great promise. Recommendations for research, test development, and clinical practice are provided.

Equating with Miditests Using IRT

ERIC Educational Resources Information Center

Fitzpatrick, Joseph; Skorupski, William P.

2016-01-01

The equating performance of two internal anchor test structures--miditests and minitests--is studied for four IRT equating methods using simulated data. Originally proposed by Sinharay and Holland, miditests are anchors that have the same mean difficulty as the overall test but less variance in item difficulties. Four popular IRT equating methods…

Application of the IRT and TRT Models to a Reading Comprehension Test

ERIC Educational Resources Information Center

Kim, Weon H.

2017-01-01

The purpose of the present study is to apply the item response theory (IRT) and testlet response theory (TRT) models to a reading comprehension test. This study applied the TRT models and the traditional IRT model to a seventh-grade reading comprehension test (n = 8,815) with eight testlets. These three models were compared to determine the best…

Relationships among Classical Test Theory and Item Response Theory Frameworks via Factor Analytic Models

ERIC Educational Resources Information Center

Kohli, Nidhi; Koran, Jennifer; Henn, Lisa

2015-01-01

There are well-defined theoretical differences between the classical test theory (CTT) and item response theory (IRT) frameworks. It is understood that in the CTT framework, person and item statistics are test- and sample-dependent. This is not the perception with IRT. For this reason, the IRT framework is considered to be theoretically superior…

Two iron-regulated transporter (IRT) genes showed differential expression in poplar trees under iron or zinc deficiency.

PubMed

Huang, Danqiong; Dai, Wenhao

2015-08-15

Two iron-regulated transporter (IRT) genes were cloned from the iron chlorosis resistant (PtG) and susceptible (PtY) Populus tremula 'Erecta' lines. Nucleotide sequence analysis showed no significant difference between PtG and PtY. The predicted proteins contain a conserved ZIP domain with 8 transmembrane (TM) regions. A ZIP signature sequence was found in the fourth TM domain. Phylogenetic analysis revealed that PtIRT1 was clustered with tomato and tobacco IRT genes that are highly responsible to iron deficiency. The PtIRT3 gene was clustered with the AtIRT3 gene that was related to zinc and iron transport in plants. Tissue specific expression indicated that PtIRT1 only expressed in the root, while PtIRT3 constitutively expressed in all tested tissues. Under iron deficiency, the expression of PtIRT1 was dramatically increased and a significantly higher transcript level was detected in PtG than in PtY. Iron deficiency also enhanced the expression of PtIRT3 in PtG. On the other hand, zinc deficiency down-regulated the expression of PtIRT1 and PtIRT3 in both PtG and PtY. Zinc accumulated significantly under iron-deficient conditions, whereas the zinc deficiency showed no significant effect on iron accumulation. A yeast complementation test revealed that the PtIRT1 and PtIRT3 genes could restore the iron uptake ability under the iron uptake-deficiency condition. The results will help understand the mechanisms of iron deficiency response in poplar trees and other woody species. Copyright © 2015 Elsevier GmbH. All rights reserved.

Practical Consequences of Item Response Theory Model Misfit in the Context of Test Equating with Mixed-Format Test Data

PubMed Central

Zhao, Yue; Hambleton, Ronald K.

2017-01-01

In item response theory (IRT) models, assessing model-data fit is an essential step in IRT calibration. While no general agreement has ever been reached on the best methods or approaches to use for detecting misfit, perhaps the more important comment based upon the research findings is that rarely does the research evaluate IRT misfit by focusing on the practical consequences of misfit. The study investigated the practical consequences of IRT model misfit in examining the equating performance and the classification of examinees into performance categories in a simulation study that mimics a typical large-scale statewide assessment program with mixed-format test data. The simulation study was implemented by varying three factors, including choice of IRT model, amount of growth/change of examinees’ abilities between two adjacent administration years, and choice of IRT scaling methods. Findings indicated that the extent of significant consequences of model misfit varied over the choice of model and IRT scaling methods. In comparison with mean/sigma (MS) and Stocking and Lord characteristic curve (SL) methods, separate calibration with linking and fixed common item parameter (FCIP) procedure was more sensitive to model misfit and more robust against various amounts of ability shifts between two adjacent administrations regardless of model fit. SL was generally the least sensitive to model misfit in recovering equating conversion and MS was the least robust against ability shifts in recovering the equating conversion when a substantial degree of misfit was present. The key messages from the study are that practical ways are available to study model fit, and, model fit or misfit can have consequences that should be considered when choosing an IRT model. Not only does the study address the consequences of IRT model misfit, but also it is our hope to help researchers and practitioners find practical ways to study model fit and to investigate the validity of particular IRT models for achieving a specified purpose, to assure that the successful use of the IRT models are realized, and to improve the applications of IRT models with educational and psychological test data. PMID:28421011

Stability of Rasch Scales over Time

ERIC Educational Resources Information Center

Taylor, Catherine S.; Lee, Yoonsun

2010-01-01

Item response theory (IRT) methods are generally used to create score scales for large-scale tests. Research has shown that IRT scales are stable across groups and over time. Most studies have focused on items that are dichotomously scored. Now Rasch and other IRT models are used to create scales for tests that include polytomously scored items.…

The Relationship between CTT and IRT Approaches in Analyzing Item Characteristics

ERIC Educational Resources Information Center

Abedalaziz, Nabeel; Leng, Chin Hai

2013-01-01

Most of the tests and inventories used by counseling psychologists have been developed using CTT; IRT derives from what is called latent trait theory. A number of important differences exist between CTT- versus IRT-based approaches to both test development and evaluation, as well as the process of scoring the response profiles of individual…

Comparing Vertical Scales Derived from Dichotomous and Polytomous IRT Models for a Test Composed of Testlets.

ERIC Educational Resources Information Center

Bishop, N. Scott; Omar, Md Hafidz

Previous research has shown that testlet structures often violate important assumptions of dichotomous item response theory (D-IRT) models, applied to item-level scores, that can in turn affect the results of many measurement applications. In this situation, polytomous IRT (P-IRT) models, applied to testlet-level scores, have been used as an…

Item Response Theory and Health Outcomes Measurement in the 21st Century

PubMed Central

Hays, Ron D.; Morales, Leo S.; Reise, Steve P.

2006-01-01

Item response theory (IRT) has a number of potential advantages over classical test theory in assessing self-reported health outcomes. IRT models yield invariant item and latent trait estimates (within a linear transformation), standard errors conditional on trait level, and trait estimates anchored to item content. IRT also facilitates evaluation of differential item functioning, inclusion of items with different response formats in the same scale, and assessment of person fit and is ideally suited for implementing computer adaptive testing. Finally, IRT methods can be helpful in developing better health outcome measures and in assessing change over time. These issues are reviewed, along with a discussion of some of the methodological and practical challenges in applying IRT methods. PMID:10982088

Calibration and tests of commercial wireless infrared thermometers

USDA-ARS?s Scientific Manuscript database

Applications of infrared thermometers (IRTs) in large agricultural fields require wireless data transmission, and IRT target temperature should have minimal sensitivity to internal detector temperature. To meet these objectives, a prototype wireless IRT system was developed at USDA Agricultural Rese...

The Reliability and Precision of Total Scores and IRT Estimates as a Function of Polytomous IRT Parameters and Latent Trait Distribution

ERIC Educational Resources Information Center

Culpepper, Steven Andrew

2013-01-01

A classic topic in the fields of psychometrics and measurement has been the impact of the number of scale categories on test score reliability. This study builds on previous research by further articulating the relationship between item response theory (IRT) and classical test theory (CTT). Equations are presented for comparing the reliability and…

A Nonparametric Approach for Assessing Goodness-of-Fit of IRT Models in a Mixed Format Test

ERIC Educational Resources Information Center

Liang, Tie; Wells, Craig S.

2015-01-01

Investigating the fit of a parametric model plays a vital role in validating an item response theory (IRT) model. An area that has received little attention is the assessment of multiple IRT models used in a mixed-format test. The present study extends the nonparametric approach, proposed by Douglas and Cohen (2001), to assess model fit of three…

A Combined IRT and SEM Approach for Individual-Level Assessment in Test-Retest Studies

ERIC Educational Resources Information Center

Ferrando, Pere J.

2015-01-01

The standard two-wave multiple-indicator model (2WMIM) commonly used to analyze test-retest data provides information at both the group and item level. Furthermore, when applied to binary and graded item responses, it is related to well-known item response theory (IRT) models. In this article the IRT-2WMIM relations are used to obtain additional…

Testing item response theory invariance of the standardized Quality-of-life Disease Impact Scale (QDIS(®)) in acute coronary syndrome patients: differential functioning of items and test.

PubMed

Deng, Nina; Anatchkova, Milena D; Waring, Molly E; Han, Kyung T; Ware, John E

2015-08-01

The Quality-of-life (QOL) Disease Impact Scale (QDIS(®)) standardizes the content and scoring of QOL impact attributed to different diseases using item response theory (IRT). This study examined the IRT invariance of the QDIS-standardized IRT parameters in an independent sample. The differential functioning of items and test (DFIT) of a static short-form (QDIS-7) was examined across two independent sources: patients hospitalized for acute coronary syndrome (ACS) in the TRACE-CORE study (N = 1,544) and chronically ill US adults in the QDIS standardization sample. "ACS-specific" IRT item parameters were calibrated and linearly transformed to compare to "standardized" IRT item parameters. Differences in IRT model-expected item, scale and theta scores were examined. The DFIT results were also compared in a standard logistic regression differential item functioning analysis. Item parameters estimated in the ACS sample showed lower discrimination parameters than the standardized discrimination parameters, but only small differences were found for thresholds parameters. In DFIT, results on the non-compensatory differential item functioning index (range 0.005-0.074) were all below the threshold of 0.096. Item differences were further canceled out at the scale level. IRT-based theta scores for ACS patients using standardized and ACS-specific item parameters were highly correlated (r = 0.995, root-mean-square difference = 0.09). Using standardized item parameters, ACS patients scored one-half standard deviation higher (indicating greater QOL impact) compared to chronically ill adults in the standardization sample. The study showed sufficient IRT invariance to warrant the use of standardized IRT scoring of QDIS-7 for studies comparing the QOL impact attributed to acute coronary disease and other chronic conditions.

Effect of Item Response Theory (IRT) Model Selection on Testlet-Based Test Equating. Research Report. ETS RR-14-19

ERIC Educational Resources Information Center

Cao, Yi; Lu, Ru; Tao, Wei

2014-01-01

The local item independence assumption underlying traditional item response theory (IRT) models is often not met for tests composed of testlets. There are 3 major approaches to addressing this issue: (a) ignore the violation and use a dichotomous IRT model (e.g., the 2-parameter logistic [2PL] model), (b) combine the interdependent items to form a…

Modern psychometrics applied in rheumatology--a systematic review.

PubMed

Siemons, Liseth; Ten Klooster, Peter M; Taal, Erik; Glas, Cees Aw; Van de Laar, Mart Afj

2012-10-31

Although item response theory (IRT) appears to be increasingly used within health care research in general, a comprehensive overview of the frequency and characteristics of IRT analyses within the rheumatic field is lacking. An overview of the use and application of IRT in rheumatology to date may give insight into future research directions and highlight new possibilities for the improvement of outcome assessment in rheumatic conditions. Therefore, this study systematically reviewed the application of IRT to patient-reported and clinical outcome measures in rheumatology. Literature searches in PubMed, Scopus and Web of Science resulted in 99 original English-language articles which used some form of IRT-based analysis of patient-reported or clinical outcome data in patients with a rheumatic condition. Both general study information and IRT-specific information were assessed. Most studies used Rasch modeling for developing or evaluating new or existing patient-reported outcomes in rheumatoid arthritis or osteoarthritis patients. Outcomes of principle interest were physical functioning and quality of life. Since the last decade, IRT has also been applied to clinical measures more frequently. IRT was mostly used for evaluating model fit, unidimensionality and differential item functioning, the distribution of items and persons along the underlying scale, and reliability. Less frequently used IRT applications were the evaluation of local independence, the threshold ordering of items, and the measurement precision along the scale. IRT applications have markedly increased within rheumatology over the past decades. To date, IRT has primarily been applied to patient-reported outcomes, however, applications to clinical measures are gaining interest. Useful IRT applications not yet widely used within rheumatology include the cross-calibration of instrument scores and the development of computerized adaptive tests which may reduce the measurement burden for both the patient and the clinician. Also, the measurement precision of outcome measures along the scale was only evaluated occasionally. Performed IRT analyses should be adequately explained, justified, and reported. A global consensus about uniform guidelines should be reached concerning the minimum number of assumptions which should be met and best ways of testing these assumptions, in order to stimulate the quality appraisal of performed IRT analyses.

Can Handheld Thermal Imaging Technology Improve Detection of Poachers in African Bushveldt?

PubMed Central

Dandy, Shantelle; Stubbs, Hannah; MacTavish, Dougal; MacTavish, Lynne

2015-01-01

Illegal hunting (poaching) is a global threat to wildlife. Anti-poaching initiatives are making increasing use of technology, such as infrared thermography (IRT), to support traditional foot and vehicle patrols. To date, the effectiveness of IRT for poacher location has not been tested under field conditions, where thermal signatures are often complex. Here, we test the hypothesis that IRT will increase the distance over which a poacher hiding in African scrub bushveldt can be detected relative to a conventional flashlight. We also test whether any increase in effectiveness is related to the cost and complexity of the equipment by comparing comparatively expensive (22000 USD) and relatively inexpensive (2000 USD) IRT devices. To test these hypotheses we employ a controlled, fully randomised, double-blind procedure to find a poacher in nocturnal field conditions in African bushveldt. Each of our 27 volunteer observers walked three times along a pathway using one detection technology on each pass in randomised order. They searched a prescribed search area of bushveldt within which the target was hiding. Hiding locations were pre-determined, randomised, and changed with each pass. Distances of first detection and positive detection were noted. All technologies could be used to detect the target. Average first detection distance for flashlight was 37.3m, improving by 19.8m to 57.1m using LIRT and by a further 11.2m to 68.3m using HIRT. Although detection distances were significantly greater for both IRTs compared to flashlight, there was no significant difference between LIRT and HIRT. False detection rates were low and there was no significant association between technology and accuracy of detection. Although IRT technology should ideally be tested in the specific environment intended before significant investment is made, we conclude that IRT technology is promising for anti-poaching patrols and that for this purpose low cost IRT units are as effective as units ten times more expensive. PMID:26110865

IRT Equating of the MCAT. MCAT Monograph.

ERIC Educational Resources Information Center

Hendrickson, Amy B.; Kolen, Michael J.

This study compared various equating models and procedures for a sample of data from the Medical College Admission Test(MCAT), considering how item response theory (IRT) equating results compare with classical equipercentile results and how the results based on use of various IRT models, observed score versus true score, direct versus linked…

Classification Consistency and Accuracy for Complex Assessments Using Item Response Theory

ERIC Educational Resources Information Center

Lee, Won-Chan

2010-01-01

In this article, procedures are described for estimating single-administration classification consistency and accuracy indices for complex assessments using item response theory (IRT). This IRT approach was applied to real test data comprising dichotomous and polytomous items. Several different IRT model combinations were considered. Comparisons…

Modern Psychometric Methodology: Applications of Item Response Theory

ERIC Educational Resources Information Center

Reid, Christine A.; Kolakowsky-Hayner, Stephanie A.; Lewis, Allen N.; Armstrong, Amy J.

2007-01-01

Item response theory (IRT) methodology is introduced as a tool for improving assessment instruments used with people who have disabilities. Need for this approach in rehabilitation is emphasized; differences between IRT and classical test theory are clarified. Concepts essential to understanding IRT are defined, necessary data assumptions are…

The Value of Item Response Theory in Clinical Assessment: A Review

ERIC Educational Resources Information Center

Thomas, Michael L.

2011-01-01

Item response theory (IRT) and related latent variable models represent modern psychometric theory, the successor to classical test theory in psychological assessment. Although IRT has become prevalent in the measurement of ability and achievement, its contributions to clinical domains have been less extensive. Applications of IRT to clinical…

Improving the Sensitivity and Positive Predictive Value in a Cystic Fibrosis Newborn Screening Program Using a Repeat Immunoreactive Trypsinogen and Genetic Analysis.

PubMed

Sontag, Marci K; Lee, Rachel; Wright, Daniel; Freedenberg, Debra; Sagel, Scott D

2016-08-01

To evaluate the performance of a new cystic fibrosis (CF) newborn screening algorithm, comprised of immunoreactive trypsinogen (IRT) in first (24-48 hours of life) and second (7-14 days of life) dried blood spot plus DNA on second dried blood spot, over existing algorithms. A retrospective review of the IRT/IRT/DNA algorithm implemented in Colorado, Wyoming, and Texas. A total of 1 520 079 newborns were screened, 32 557 (2.1%) had abnormal first IRT; 8794 (0.54%) on second. Furthermore, 14 653 mutation analyses were performed; 1391 newborns were referred for diagnostic testing; 274 newborns were diagnosed; and 201/274 (73%) of newborns had 2 mutations on the newborn screening CFTR panel. Sensitivity was 96.2%, compared with sensitivity of 76.1% observed with IRT/IRT (105 ng/mL cut-offs, P < .0001). The ratio of newborns with CF to heterozygote carriers was 1:2.5, and newborns with CF to newborns with CFTR-related metabolic syndrome was 10.8:1. The overall positive predictive value was 20%. The median age of diagnosis was 28, 30, and 39.5 days in the 3 states. IRT/IRT/DNA is more sensitive than IRT/IRT because of lower cut-offs (∼97 percentile or 60 ng/mL); higher cut-offs in IRT/IRT programs (>99 percentile, 105 ng/mL) would not achieve sufficient sensitivity. Carrier identification and identification of newborns with CFTR-related metabolic syndrome is less common in IRT/IRT/DNA compared with IRT/DNA. The time to diagnosis is nominally longer, but diagnosis can be achieved in the neonatal period and opportunities to further improve timeliness have been enacted. IRT/IRT/DNA algorithm should be considered by programs with 2 routine screens. Copyright © 2016 Elsevier Inc. All rights reserved.

An Introduction to Item Response Theory for Health Behavior Researchers

ERIC Educational Resources Information Center

Warne, Russell T.; McKyer, E. J. Lisako; Smith, Matthew L.

2012-01-01

Objective: To introduce item response theory (IRT) to health behavior researchers by contrasting it with classical test theory and providing an example of IRT in health behavior. Method: Demonstrate IRT by fitting the 2PL model to substance-use survey data from the Adolescent Health Risk Behavior questionnaire (n = 1343 adolescents). Results: An…

A Bayesian Beta-Mixture Model for Nonparametric IRT (BBM-IRT)

ERIC Educational Resources Information Center

Arenson, Ethan A.; Karabatsos, George

2017-01-01

Item response models typically assume that the item characteristic (step) curves follow a logistic or normal cumulative distribution function, which are strictly monotone functions of person test ability. Such assumptions can be overly-restrictive for real item response data. We propose a simple and more flexible Bayesian nonparametric IRT model…

Item Response Theory: Overview, Applications, and Promise for Institutional Research

ERIC Educational Resources Information Center

Bowman, Nicholas A.; Herzog, Serge; Sharkness, Jessica

2014-01-01

Item Response Theory (IRT) is a measurement theory that is ideal for scale and test development in institutional research, but it is not without its drawbacks. This chapter provides an overview of IRT, describes an example of its use, and highlights the pros and cons of using IRT in applied settings.

Adaptive Testing without IRT.

ERIC Educational Resources Information Center

Yan, Duanli; Lewis, Charles; Stocking, Martha

It is unrealistic to suppose that standard item response theory (IRT) models will be appropriate for all new and currently considered computer-based tests. In addition to developing new models, researchers will need to give some attention to the possibility of constructing and analyzing new tests without the aid of strong models. Computerized…

The Performance of IRT Model Selection Methods with Mixed-Format Tests

ERIC Educational Resources Information Center

Whittaker, Tiffany A.; Chang, Wanchen; Dodd, Barbara G.

2012-01-01

When tests consist of multiple-choice and constructed-response items, researchers are confronted with the question of which item response theory (IRT) model combination will appropriately represent the data collected from these mixed-format tests. This simulation study examined the performance of six model selection criteria, including the…

Examining Differential Item Functioning: IRT-Based Detection in the Framework of Confirmatory Factor Analysis

ERIC Educational Resources Information Center

Dimitrov, Dimiter M.

2017-01-01

This article offers an approach to examining differential item functioning (DIF) under its item response theory (IRT) treatment in the framework of confirmatory factor analysis (CFA). The approach is based on integrating IRT- and CFA-based testing of DIF and using bias-corrected bootstrap confidence intervals with a syntax code in Mplus.

Identifying Aberrant Responding: Use of Multiple Measures

ERIC Educational Resources Information Center

Steinkamp, Susan Christa

2017-01-01

For test scores that rely on the accurate estimation of ability via an IRT model, their use and interpretation is dependent upon the assumption that the IRT model fits the data. Examinees who do not put forth full effort in answering test questions, have prior knowledge of test content, or do not approach a test with the intent of answering…

Demonstrating the Difference between Classical Test Theory and Item Response Theory Using Derived Test Data

ERIC Educational Resources Information Center

Magno, Carlo

2009-01-01

The present report demonstrates the difference between classical test theory (CTT) and item response theory (IRT) approach using an actual test data for chemistry junior high school students. The CTT and IRT were compared across two samples and two forms of test on their item difficulty, internal consistency, and measurement errors. The specific…

Aerobic power and field test results of amateur 15-a-side rugby union players.

PubMed

Sant'anna, Ricardo T; de Souza Castro, Flávio A

2017-12-01

The aim of the present study was to verify whether it is possible to predict aerobic power in amateur 15-a-side rugby union players through the Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IRT1) and the 5-meter Multiple Shuttle Test (5-m MST). Forty-two amateur players - 22 forwards and 20 backs - were evaluated in three phases: 1) maximum treadmill test in the laboratory; 2) field test set by a drawing in the first phase; and 3) second field test. Descriptive, comparison, correlation, regression and level of agreement analyses were performed. Backs, when compared to forwards, showed a higher VO2max (61.7±15 mL/kg/min and 51.6±10.1 mL/kg/min, respectively), Yo-Yo IRT1 final level (16.4±0.8 and 14.9±0.9, respectively) and Yo-Yo IRT1 total distance (1283.3±312.5 m and 792±277.6 m, respectively), and a higher final distance in the 5-m MST (686.8±36.6 and 642.9±46.5, respectively). Significant correlations were found between the result and the total distance on the Yo-Yo IRT1 and the VO2max (r=0.425 and r=0.459, respectively). Using the total distance covered in the Yo-Yo IRT1, the VO2max of amateur 15-a-side rugby union players can be estimated through the equation VO2max = 0.016 × (DIST Yo‑Yo) + 40.578. Yo-Yo IRT1 is most useful when the objective is to evaluate the aerobic power of amateur RU players in comparison with the 5-m MST.

An Alternative Methodology for Creating Parallel Test Forms Using the IRT Information Function.

ERIC Educational Resources Information Center

Ackerman, Terry A.

The purpose of this paper is to report results on the development of a new computer-assisted methodology for creating parallel test forms using the item response theory (IRT) information function. Recently, several researchers have approached test construction from a mathematical programming perspective. However, these procedures require…

Using Item Response Theory and Adaptive Testing in Online Career Assessment

ERIC Educational Resources Information Center

Betz, Nancy E.; Turner, Brandon M.

2011-01-01

The present article describes the potential utility of item response theory (IRT) and adaptive testing for scale evaluation and for web-based career assessment. The article describes the principles of both IRT and adaptive testing and then illustrates these with reference to data analyses and simulation studies of the Career Confidence Inventory…

Exploring Unidimensional Proficiency Classification Accuracy from Multidimensional Data in a Vertical Scaling Context

ERIC Educational Resources Information Center

Kroopnick, Marc Howard

2010-01-01

When Item Response Theory (IRT) is operationally applied for large scale assessments, unidimensionality is typically assumed. This assumption requires that the test measures a single latent trait. Furthermore, when tests are vertically scaled using IRT, the assumption of unidimensionality would require that the battery of tests across grades…

A Decision-Tree Approach to Cost Comparison of Newborn Screening Strategies for Cystic Fibrosis

PubMed Central

Wells, Janelle; Rosenberg, Marjorie; Hoffman, Gary; Anstead, Michael

2012-01-01

OBJECTIVE: Because cystic fibrosis can be difficult to diagnose and treat early, newborn screening programs have rapidly developed nationwide but methods vary widely. We therefore investigated the costs and consequences or specific outcomes of the 2 most commonly used methods. METHODS: With available data on screening and follow-up, we used a simulation approach with decision trees to compare immunoreactive trypsinogen (IRT) screening followed by a second IRT test against an IRT/DNA analysis. By using a Monte Carlo simulation program, variation in the model parameters for counts at various nodes of the decision trees, as well as for costs, are included and applied to fictional cohorts of 100 000 newborns. The outcome measures included the numbers of newborns given a diagnosis of cystic fibrosis and costs of screening strategy at each branch and cost per newborn. RESULTS: Simulations revealed a substantial number of potential missed diagnoses for the IRT/IRT system versus IRT/DNA. Although the IRT/IRT strategy with commonly used cutoff values offers an average overall cost savings of $2.30 per newborn, a breakdown of costs by societal segments demonstrated higher out-of-pocket costs for families. Two potential system failures causing delayed diagnoses were identified relating to the screening protocols and the follow-up system. CONCLUSIONS: The IRT/IRT screening algorithm reduces the costs to laboratories and insurance companies but has more system failures. IRT/DNA offers other advantages, including fewer delayed diagnoses and lower out-of-pocket costs to families. PMID:22291119

Application of an IRT Polytomous Model for Measuring Health Related Quality of Life

ERIC Educational Resources Information Center

Tejada, Antonio J. Rojas; Rojas, Oscar M. Lozano

2005-01-01

Background: The Item Response Theory (IRT) has advantages for measuring Health Related Quality of Life (HRQOL) as opposed to the Classical Tests Theory (CTT). Objectives: To present the results of the application of a polytomous model based on IRT, specifically, the Rating Scale Model (RSM), to measure HRQOL with the EORTC QLQ-C30. Methods: 103…

A Comment on Early Student Blunders on Computer-Based Adaptive Tests

ERIC Educational Resources Information Center

Green, Bert F.

2011-01-01

This article refutes a recent claim that computer-based tests produce biased scores for very proficient test takers who make mistakes on one or two initial items and that the "bias" can be reduced by using a four-parameter IRT model. Because the same effect occurs with pattern scores on nonadaptive tests, the effect results from IRT scoring, not…

NDT detection and quantification of induced defects on composite helicopter rotor blade and UAV wing sections

NASA Astrophysics Data System (ADS)

Findeis, Dirk; Gryzagoridis, Jasson; Musonda, Vincent

2008-09-01

Digital Shearography and Infrared Thermography (IRT) techniques were employed to test non-destructively samples from aircraft structures of composite material nature. Background information on the techniques is presented and it is noted that much of the inspection work reviewed in the literature has focused on qualitative evaluation of the defects rather than quantitative. There is however, need to quantify the defects if the threshold rejection criterion of whether the component inspected is fit for service has to be established. In this paper an attempt to quantify induced defects on a helicopter main rotor blade and Unmanned Aerospace Vehicle (UAV) composite material is presented. The fringe patterns exhibited by Digital Shearography were used to quantify the defects by relating the number of fringes created to the depth of the defect or flaw. Qualitative evaluation of defects with IRT was achieved through a hot spot temperature indication above the flaw on the surface of the material. The results of the work indicate that the Shearographic technique proved to be more sensitive than the IRT technique. It should be mentioned that there is "no set standard procedure" tailored for testing of composites. Each composite material tested is more likely to respond differently to defect detection and this depends generally on the component geometry and a suitable selection of the loading system to suit a particular test. The experimental procedure that is reported in this paper can be used as a basis for designing a testing or calibration procedure for defects detection on any particular composite material component or structure.

Effects of Differential Item Functioning on Examinees' Test Performance and Reliability of Test

ERIC Educational Resources Information Center

Lee, Yi-Hsuan; Zhang, Jinming

2017-01-01

Simulations were conducted to examine the effect of differential item functioning (DIF) on measurement consequences such as total scores, item response theory (IRT) ability estimates, and test reliability in terms of the ratio of true-score variance to observed-score variance and the standard error of estimation for the IRT ability parameter. The…

Standard Error Estimation of 3PL IRT True Score Equating with an MCMC Method

ERIC Educational Resources Information Center

Liu, Yuming; Schulz, E. Matthew; Yu, Lei

2008-01-01

A Markov chain Monte Carlo (MCMC) method and a bootstrap method were compared in the estimation of standard errors of item response theory (IRT) true score equating. Three test form relationships were examined: parallel, tau-equivalent, and congeneric. Data were simulated based on Reading Comprehension and Vocabulary tests of the Iowa Tests of…

The Effect of Including or Excluding Students with Testing Accommodations on IRT Calibrations.

ERIC Educational Resources Information Center

Karkee, Thakur; Lewis, Dan M.; Barton, Karen; Haug, Carolyn

This study aimed to determine the degree to which the inclusion of accommodated students with disabilities in the calibration sample affects the characteristics of item parameters and the test results. Investigated were effects on test reliability, item fit to the applicable item response theory (IRT) model, item parameter estimates, and students'…

Comparison of IRT and CTT Using Secondary School Reading Comprehension Assessments

ERIC Educational Resources Information Center

Coggins, Joanne V.; Kim, Jwa K.; Briggs, Laura C.

2017-01-01

The Gates-MacGinitie Reading Comprehension Test, fourth edition (GMRT-4) and the ACT Reading Tests (ACT-R) were administered to 423 high school students in order to explore the similarities and dissimilarities of data produced through classical test theory (CTT) and item response theory (IRT) analysis. Despite the many advantages of IRT…

Mixture IRT Model with a Higher-Order Structure for Latent Traits

ERIC Educational Resources Information Center

Huang, Hung-Yu

2017-01-01

Mixture item response theory (IRT) models have been suggested as an efficient method of detecting the different response patterns derived from latent classes when developing a test. In testing situations, multiple latent traits measured by a battery of tests can exhibit a higher-order structure, and mixtures of latent classes may occur on…

The Estimation of the IRT Reliability Coefficient and Its Lower and Upper Bounds, with Comparisons to CTT Reliability Statistics

ERIC Educational Resources Information Center

Kim, Seonghoon; Feldt, Leonard S.

2010-01-01

The primary purpose of this study is to investigate the mathematical characteristics of the test reliability coefficient rho[subscript XX'] as a function of item response theory (IRT) parameters and present the lower and upper bounds of the coefficient. Another purpose is to examine relative performances of the IRT reliability statistics and two…

Likelihood-Ratio DIF Testing: Effects of Nonnormality

ERIC Educational Resources Information Center

Woods, Carol M.

2008-01-01

Differential item functioning (DIF) occurs when an item has different measurement properties for members of one group versus another. Likelihood-ratio (LR) tests for DIF based on item response theory (IRT) involve statistically comparing IRT models that vary with respect to their constraints. A simulation study evaluated how violation of the…

IRT-Estimated Reliability for Tests Containing Mixed Item Formats

ERIC Educational Resources Information Center

Shu, Lianghua; Schwarz, Richard D.

2014-01-01

As a global measure of precision, item response theory (IRT) estimated reliability is derived for four coefficients (Cronbach's a, Feldt-Raju, stratified a, and marginal reliability). Models with different underlying assumptions concerning test-part similarity are discussed. A detailed computational example is presented for the targeted…

Bayesian Estimation of Multi-Unidimensional Graded Response IRT Models

ERIC Educational Resources Information Center

Kuo, Tzu-Chun

2015-01-01

Item response theory (IRT) has gained an increasing popularity in large-scale educational and psychological testing situations because of its theoretical advantages over classical test theory. Unidimensional graded response models (GRMs) are useful when polytomous response items are designed to measure a unified latent trait. They are limited in…

Unidimensional Interpretations for Multidimensional Test Items

ERIC Educational Resources Information Center

Kahraman, Nilufer

2013-01-01

This article considers potential problems that can arise in estimating a unidimensional item response theory (IRT) model when some test items are multidimensional (i.e., show a complex factorial structure). More specifically, this study examines (1) the consequences of model misfit on IRT item parameter estimates due to unintended minor item-level…

Using item response theory to investigate the structure of anticipated affect: do self-reports about future affective reactions conform to typical or maximal models?

PubMed

Zampetakis, Leonidas A; Lerakis, Manolis; Kafetsios, Konstantinos; Moustakis, Vassilis

2015-01-01

In the present research, we used item response theory (IRT) to examine whether effective predictions (anticipated affect) conforms to a typical (i.e., what people usually do) or a maximal behavior process (i.e., what people can do). The former, correspond to non-monotonic ideal point IRT models, whereas the latter correspond to monotonic dominance IRT models. A convenience, cross-sectional student sample (N = 1624) was used. Participants were asked to report on anticipated positive and negative affect around a hypothetical event (emotions surrounding the start of a new business). We carried out analysis comparing graded response model (GRM), a dominance IRT model, against generalized graded unfolding model, an unfolding IRT model. We found that the GRM provided a better fit to the data. Findings suggest that the self-report responses to anticipated affect conform to dominance response process (i.e., maximal behavior). The paper also discusses implications for a growing literature on anticipated affect.

Using item response theory to investigate the structure of anticipated affect: do self-reports about future affective reactions conform to typical or maximal models?

PubMed Central

Zampetakis, Leonidas A.; Lerakis, Manolis; Kafetsios, Konstantinos; Moustakis, Vassilis

2015-01-01

In the present research, we used item response theory (IRT) to examine whether effective predictions (anticipated affect) conforms to a typical (i.e., what people usually do) or a maximal behavior process (i.e., what people can do). The former, correspond to non-monotonic ideal point IRT models, whereas the latter correspond to monotonic dominance IRT models. A convenience, cross-sectional student sample (N = 1624) was used. Participants were asked to report on anticipated positive and negative affect around a hypothetical event (emotions surrounding the start of a new business). We carried out analysis comparing graded response model (GRM), a dominance IRT model, against generalized graded unfolding model, an unfolding IRT model. We found that the GRM provided a better fit to the data. Findings suggest that the self-report responses to anticipated affect conform to dominance response process (i.e., maximal behavior). The paper also discusses implications for a growing literature on anticipated affect. PMID:26441806

A Comparison of Three IRT Approaches to Examinee Ability Change Modeling in a Single-Group Anchor Test Design

ERIC Educational Resources Information Center

Paek, Insu; Park, Hyun-Jeong; Cai, Li; Chi, Eunlim

2014-01-01

Typically a longitudinal growth modeling based on item response theory (IRT) requires repeated measures data from a single group with the same test design. If operational or item exposure problems are present, the same test may not be employed to collect data for longitudinal analyses and tests at multiple time points are constructed with unique…

Development and validation of a new knowledge, attitude, belief and practice questionnaire on leptospirosis in Malaysia.

PubMed

Zahiruddin, Wan Mohd; Arifin, Wan Nor; Mohd-Nazri, Shafei; Sukeri, Surianti; Zawaha, Idris; Bakar, Rahman Abu; Hamat, Rukman Awang; Malina, Osman; Jamaludin, Tengku Zetty Maztura Tengku; Pathman, Arumugam; Mas-Harithulfadhli-Agus, Ab Rahman; Norazlin, Idris; Suhailah, Binti Samsudin; Saudi, Siti Nor Sakinah; Abdullah, Nurul Munirah; Nozmi, Noramira; Zainuddin, Abdul Wahab; Aziah, Daud

2018-03-07

In Malaysia, leptospirosis is considered an endemic disease, with sporadic outbreaks following rainy or flood seasons. The objective of this study was to develop and validate a new knowledge, attitude, belief and practice (KABP) questionnaire on leptospirosis for use in urban and rural populations in Malaysia. The questionnaire comprised development and validation stages. The development phase encompassed a literature review, expert panel review, focus-group testing, and evaluation. The validation phase consisted of exploratory and confirmatory parts to verify the psychometric properties of the questionnaire. A total of 214 and 759 participants were recruited from two Malaysian states, Kelantan and Selangor respectively, for the validation phase. The participants comprised urban and rural communities with a high reported incidence of leptospirosis. The knowledge section of the validation phase utilized item response theory (IRT) analysis. The attitude and belief sections utilized exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). The development phase resulted in a questionnaire that included four main sections: knowledge, attitude, belief, and practice. In the exploratory phase, as shown by the IRT analysis of knowledge about leptospirosis, the difficulty and discrimination values of the items were acceptable, with the exception of two items. Based on the EFA, the psychometric properties of the attitude, belief, and practice sections were poor. Thus, these sections were revised, and no further factor analysis of the practice section was conducted. In the confirmatory stage, the difficulty and discrimination values of the items in the knowledge section remained within the acceptable range. The CFA of the attitude section resulted in a good-fitting two-factor model. The CFA of the belief section retained low number of items, although the analysis resulted in a good fit in the final three-factor model. Based on the IRT analysis and factor analytic evidence, the knowledge and attitude sections of the KABP questionnaire on leptospirosis were psychometrically valid. However, the psychometric properties of the belief section were unsatisfactory, despite being revised after the initial validation study. Further development of this section is warranted in future studies.

Statistical Indexes for Monitoring Item Behavior under Computer Adaptive Testing Environment.

ERIC Educational Resources Information Center

Zhu, Renbang; Yu, Feng; Liu, Su

A computerized adaptive test (CAT) administration usually requires a large supply of items with accurately estimated psychometric properties, such as item response theory (IRT) parameter estimates, to ensure the precision of examinee ability estimation. However, an estimated IRT model of a given item in any given pool does not always correctly…

Comparison of IRT Likelihood Ratio Test and Logistic Regression DIF Detection Procedures

ERIC Educational Resources Information Center

Atar, Burcu; Kamata, Akihito

2011-01-01

The Type I error rates and the power of IRT likelihood ratio test and cumulative logit ordinal logistic regression procedures in detecting differential item functioning (DIF) for polytomously scored items were investigated in this Monte Carlo simulation study. For this purpose, 54 simulation conditions (combinations of 3 sample sizes, 2 sample…

The Robustness of IRT-Based Vertical Scaling Methods to Violation of Unidimensionality

ERIC Educational Resources Information Center

Yin, Liqun

2013-01-01

In recent years, many states have adopted Item Response Theory (IRT) based vertically scaled tests due to their compelling features in a growth-based accountability context. However, selection of a practical and effective calibration/scaling method and proper understanding of issues with possible multidimensionality in the test data is critical to…

Results and Conclusions from the NASA Isokinetic Total Water Content Probe 2009 IRT Test

NASA Technical Reports Server (NTRS)

Reehorst, Andrew; Brinker, David

2010-01-01

The NASA Glenn Research Center has developed and tested a Total Water Content Isokinetic Sampling Probe. Since, by its nature, it is not sensitive to cloud water particle phase nor size, it is particularly attractive to support super-cooled large droplet and high ice water content aircraft icing studies. The instrument comprises the Sampling Probe, Sample Flow Control, and Water Vapor Measurement subsystems. Results and conclusions are presented from probe tests in the NASA Glenn Icing Research Tunnel (IRT) during January and February 2009. The use of reference probe heat and the control of air pressure in the water vapor measurement subsystem are discussed. Several run-time error sources were found to produce identifiable signatures that are presented and discussed. Some of the differences between measured Isokinetic Total Water Content Probe and IRT calibration seems to be caused by tunnel humidification and moisture/ice crystal blow around. Droplet size, airspeed, and liquid water content effects also appear to be present in the IRT calibration. Based upon test results, the authors provide recommendations for future Isokinetic Total Water Content Probe development.

Further Evaluation of Scaling Methods for Rotorcraft Icing

NASA Technical Reports Server (NTRS)

Tsao, Jen-Ching; Kreeger, Richard E.

2012-01-01

The paper will present experimental results from two recent icing tests in the NASA Glenn Icing Research Tunnel (IRT). The first test, conducted in February 2009, was to evaluate the current recommended scaling methods for fixed wing on representative rotor airfoils at fixed angle of attack. For this test, scaling was based on the modified Ruff method with scale velocity determined by constant Weber number and water film Weber number. Models were un-swept NACA 0012 wing sections. The reference model had a chord of 91.4 cm and scale model had a chord of 35.6 cm. Reference tests were conducted with velocity of 100 kt (52 m/s), droplet medium volume diameter (MVD) 195 m, and stagnation-point freezing fractions of 0.3 and 0.5 at angle of attack of 5deg and 7deg . It was shown that good ice shape scaling was achieved with constant Weber number for NACA 0012 airfoils with angle of attack up to 7deg . The second test, completed in May 2010, was primarily focused on obtaining transient and steady-state iced aerodynamics, ice accretion and shedding, and thermal icing validation data from an oscillating airfoil section over some selected ranges of icing conditions and blade assembly operational configurations. The model used was a 38.1-cm chord Sikorsky SC2110 airfoil section installed on an airfoil test apparatus with oscillating capability in the IRT. For two test conditions, size and condition scaling were performed. It was shown that good ice shape scaling was achieved for SC2110 airfoil at dynamic pitching motion. The data obtained will be applicable for future main rotor blade and tail rotor blade applications.

Method to Generate Full-Span Ice Shape on Swept Wing Using Icing Tunnel Data

NASA Technical Reports Server (NTRS)

Lee, Sam; Camello, Stephanie

2015-01-01

There is a collaborative research program by NASA, FAA, ONERA, and university partners to improve the fidelity of experimental and computational simulation methods for swept-wing ice accretion formulations and resultant aerodynamic effects on large transport aircraft. This research utilizes a 65 scale Common Research Model as the baseline configuration. In order to generate the ice shapes for the aerodynamic testing, ice-accretion testing will be conducted in the NASA Icing Research Tunnel utilizing hybrid model from the 20, 64, and 83 spanwise locations. The models will have full-scale leading edges with truncated chord in order to fit the IRT test section. The ice shapes from the IRT tests will be digitized using a commercially available articulated-arm 3D laser scanning system. The methodology to acquire 3D ice shapes using a laser scanner was developed and validated in a previous research effort. Each of these models will yield a 1.5ft span of ice than can be used. However, a full-span ice accretion will require 75 ft span of ice. This means there will be large gaps between these spanwise ice sections that must be filled, while maintaining all of the important aerodynamic features. A method was developed to generate a full-span ice shape from the three 1.5 ft span ice shapes from the three models.

The Impact of Test Dimensionality, Common-Item Set Format, and Scale Linking Methods on Mixed-Format Test Equating

ERIC Educational Resources Information Center

Öztürk-Gübes, Nese; Kelecioglu, Hülya

2016-01-01

The purpose of this study was to examine the impact of dimensionality, common-item set format, and different scale linking methods on preserving equity property with mixed-format test equating. Item response theory (IRT) true-score equating (TSE) and IRT observed-score equating (OSE) methods were used under common-item nonequivalent groups design.…

Comparing the Fit of Item Response Theory and Factor Analysis Models

ERIC Educational Resources Information Center

Maydeu-Olivares, Alberto; Cai, Li; Hernandez, Adolfo

2011-01-01

Linear factor analysis (FA) models can be reliably tested using test statistics based on residual covariances. We show that the same statistics can be used to reliably test the fit of item response theory (IRT) models for ordinal data (under some conditions). Hence, the fit of an FA model and of an IRT model to the same data set can now be…

The Effect of Fasting Duration on Baseline Blood Glucose Concentration, Blood Insulin Concentration, Glucose/Insulin Ratio, Oral Sugar Test, and Insulin Response Test Results in Horses.

PubMed

Bertin, F R; Taylor, S D; Bianco, A W; Sojka-Kritchevsky, J E

2016-09-01

Published descriptions of the oral sugar test (OST) and insulin response test (IRT) have been inconsistent when specifying the protocol for fasting horses before testing. The purpose of our study was to examine the effect of fasting duration on blood glucose concentration, blood insulin concentration, glucose/insulin ratio, OST, and IRT results in horses. Ten healthy adult horses. Both OST and IRT were performed on horses without fasting and after fasting for 3, 6, and 12 hours. Thus, 8 tests were performed per horse in a randomized order. Blood collected at the initial time point of the OST was analysed for both blood glucose and serum insulin concentrations so that baseline concentrations and the glucose/insulin ratio could be determined. Unless fasted, horses had free-choice access to grass hay. There was no effect of fasting and fasting duration on blood glucose concentration, serum insulin concentration, glucose/insulin ratio, or the OST. Response to insulin in the IRT was decreased in fasted horses. The effect increased with fasting duration, with the least response to insulin administration after a 12-hour fast. These data indicate that insulin sensitivity is not a fixed trait in horses. Fasting a horse is not recommended for a glucose/insulin ratio or IRT, and fasting a horse for 3 hours is recommended for the OST. Copyright © 2016 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

In-flight investigations of the unsteady behaviour of the boundary layer with infrared thermography

NASA Astrophysics Data System (ADS)

Szewczyk, Mariusz; Smusz, Robert; de Groot, Klaus; Meyer, Joerg; Kucaba-Pietal, Anna; Rzucidlo, Pawel

2017-04-01

Infrared thermography (IRT) has been well established in wind tunnel and flight tests for the last decade. Former applications of IRT were focused, in nearly all cases, on steady measurements. In the last years, requirements of unsteady IRT measurements (up to 10 Hz) have been formulated, but the problem of a very slow thermal response of common materials of wind tunnel models or airplane components has to be overcome by finding a surface modification with a fast thermal response (low heat capacity, low thermal conductivity and high thermal diffusivity). Therefore, lab investigations of potential material combinations and flight tests with a ‘low cost’ aircraft, i.e. a glider with a modified wing surface, were conducted. In order to induce unsteady conditions (rapid change of laminar-turbulent boundary layer transition), special maneuvers of a glider during IRT measurements were performed.

Scale refinement and initial evaluation of a behavioral health function measurement tool for work disability evaluation.

PubMed

Marfeo, Elizabeth E; Ni, Pengsheng; Haley, Stephen M; Bogusz, Kara; Meterko, Mark; McDonough, Christine M; Chan, Leighton; Rasch, Elizabeth K; Brandt, Diane E; Jette, Alan M

2013-09-01

To use item response theory (IRT) data simulations to construct and perform initial psychometric testing of a newly developed instrument, the Social Security Administration Behavioral Health Function (SSA-BH) instrument, that aims to assess behavioral health functioning relevant to the context of work. Cross-sectional survey followed by IRT calibration data simulations. Community. Sample of individuals applying for Social Security Administration disability benefits: claimants (n=1015) and a normative comparative sample of U.S. adults (n=1000). None. SSA-BH measurement instrument. IRT analyses supported the unidimensionality of 4 SSA-BH scales: mood and emotions (35 items), self-efficacy (23 items), social interactions (6 items), and behavioral control (15 items). All SSA-BH scales demonstrated strong psychometric properties including reliability, accuracy, and breadth of coverage. High correlations of the simulated 5- or 10-item computer adaptive tests with the full item bank indicated robust ability of the computer adaptive testing approach to comprehensively characterize behavioral health function along 4 distinct dimensions. Initial testing and evaluation of the SSA-BH instrument demonstrated good accuracy, reliability, and content coverage along all 4 scales. Behavioral function profiles of Social Security Administration claimants were generated and compared with age- and sex-matched norms along 4 scales: mood and emotions, behavioral control, social interactions, and self-efficacy. Using the computer adaptive test-based approach offers the ability to collect standardized, comprehensive functional information about claimants in an efficient way, which may prove useful in the context of the Social Security Administration's work disability programs. Copyright © 2013 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Using a Linear Regression Method to Detect Outliers in IRT Common Item Equating

ERIC Educational Resources Information Center

He, Yong; Cui, Zhongmin; Fang, Yu; Chen, Hanwei

2013-01-01

Common test items play an important role in equating alternate test forms under the common item nonequivalent groups design. When the item response theory (IRT) method is applied in equating, inconsistent item parameter estimates among common items can lead to large bias in equated scores. It is prudent to evaluate inconsistency in parameter…

Robust Scale Transformation Methods in IRT True Score Equating under Common-Item Nonequivalent Groups Design

ERIC Educational Resources Information Center

He, Yong

2013-01-01

Common test items play an important role in equating multiple test forms under the common-item nonequivalent groups design. Inconsistent item parameter estimates among common items can lead to large bias in equated scores for IRT true score equating. Current methods extensively focus on detection and elimination of outlying common items, which…

A Comparison of IRT Proficiency Estimation Methods under Adaptive Multistage Testing

ERIC Educational Resources Information Center

Kim, Sooyeon; Moses, Tim; Yoo, Hanwook

2015-01-01

This inquiry is an investigation of item response theory (IRT) proficiency estimators' accuracy under multistage testing (MST). We chose a two-stage MST design that includes four modules (one at Stage 1, three at Stage 2) and three difficulty paths (low, middle, high). We assembled various two-stage MST panels (i.e., forms) by manipulating two…

Examining the Effectiveness of Test Accommodation Using DIF and a Mixture IRT Model

ERIC Educational Resources Information Center

Cho, Hyun-Jeong; Lee, Jaehoon; Kingston, Neal

2012-01-01

This study examined the validity of test accommodation in third-eighth graders using differential item functioning (DIF) and mixture IRT models. Two data sets were used for these analyses. With the first data set (N = 51,591) we examined whether item type (i.e., story, explanation, straightforward) or item features were associated with item…

How Often Is the Misfit of Item Response Theory Models Practically Significant?

ERIC Educational Resources Information Center

Sinharay, Sandip; Haberman, Shelby J.

2014-01-01

Standard 3.9 of the Standards for Educational and Psychological Testing ([, 1999]) demands evidence of model fit when item response theory (IRT) models are employed to data from tests. Hambleton and Han ([Hambleton, R. K., 2005]) and Sinharay ([Sinharay, S., 2005]) recommended the assessment of practical significance of misfit of IRT models, but…

Application of a General Polytomous Testlet Model to the Reading Section of a Large-Scale English Language Assessment. Research Report. ETS RR-10-21

ERIC Educational Resources Information Center

Li, Yanmei; Li, Shuhong; Wang, Lin

2010-01-01

Many standardized educational tests include groups of items based on a common stimulus, known as "testlets". Standard unidimensional item response theory (IRT) models are commonly used to model examinees' responses to testlet items. However, it is known that local dependence among testlet items can lead to biased item parameter estimates…

Development of indirect ring tension test for fracture characterization of asphalt mixtures

NASA Astrophysics Data System (ADS)

Zeinali Siavashani, Alireza

Low temperature cracking is a major distress in asphalt pavements. Several test configurations have been introduced to characterize the fracture properties of hot mix (HMA); however, most are considered to be research tools due to the complexity of the test methods or equipment. This dissertation describes the development of the indirect ring tension (IRT) fracture test for HMA, which was designed to be an effective and user-friendly test that could be deployed at the Department of Transportation level. The primary advantages of this innovative and yet practical test include: relatively large fracture surface test zone, simplicity of the specimen geometry, widespread availability of the required test equipment, and ability to test laboratory compacted specimens as well as field cores. Numerical modeling was utilized to calibrate the stress intensity factor formula of the IRT fracture test for various specimen dimensions. The results of this extensive analysis were encapsulated in a single equation. To develop the test procedure, a laboratory study was conducted to determine the optimal test parameters for HMA material. An experimental plan was then developed to evaluate the capability of the test in capturing the variations in the mix properties, asphalt pavement density, asphalt material aging, and test temperature. Five plant-produced HMA mixtures were used in this extensive study, and the results revealed that the IRT fracture test is highly repeatable, and capable of capturing the variations in the fracture properties of HMA. Furthermore, an analytical model was developed based on the viscoelastic properties of HMA to estimate the maximum allowable crack size for the pavements in the experimental study. This analysis indicated that the low-temperature cracking potential of the asphalt mixtures is highly sensitive to the fracture toughness and brittleness of the HMA material. Additionally, the IRT fracture test data seemed to correlate well with the data from the distress survey which was conducted on the pavements after five years of service. The maximum allowable crack size analysis revealed that a significant improvement could be realized in terms of the pavements performance if the HMA were to be compacted to a higher density. Finally, the IRT fracture test data were compared to the results of the disk-shaped compact [DC(t)] test. The results of the two tests showed a strong correlation; however, the IRT test seemed to be more repeatable. KEYWORDS: Asphalt Pavement, Low-Temperature Cracking, Fracture Mechanics, Material Characterization, Laboratory Testing.

Item response theory in personality assessment: a demonstration using the MMPI-2 depression scale.

PubMed

Childs, R A; Dahlstrom, W G; Kemp, S M; Panter, A T

2000-03-01

Item response theory (IRT) analyses have, over the past 3 decades, added much to our understanding of the relationships among and characteristics of test items, as revealed in examinees response patterns. Assessment instruments used outside the educational context have only infrequently been analyzed using IRT, however. This study demonstrates the relevance of IRT to personality data through analyses of Scale 2 (the Depression Scale) on the revised Minnesota Multiphasic Personality Inventory (MMPI-2). A rich set of hypotheses regarding the items on this scale, including contrasts among the Harris-Lingoes and Wiener-Harmon subscales and differences in the items measurement characteristics for men and women, are investigated through the IRT analyses.

Experimental study on infrared radiation temperature field of concrete under uniaxial compression

NASA Astrophysics Data System (ADS)

Lou, Quan; He, Xueqiu

2018-05-01

Infrared thermography, as a nondestructive, non-contact and real-time monitoring method, has great significance in assessing the stability of concrete structure and monitoring its failure. It is necessary to conduct in depth study on the mechanism and application of infrared radiation (IR) of concrete failure under loading. In this paper, the concrete specimens with size of 100 × 100 × 100 mm were adopted to carry out the uniaxial compressions for the IR tests. The distribution of IR temperatures (IRTs), surface topography of IRT field and the reconstructed IR images were studied. The results show that the IRT distribution follows the Gaussian distribution, and the R2 of Gaussian fitting changes along with the loading time. The abnormities of R2 and AE counts display the opposite variation trends. The surface topography of IRT field is similar to the hyperbolic paraboloid, which is related to the stress distribution in the sample. The R2 of hyperbolic paraboloid fitting presents an upward trend prior to the fracture which enables to change the IRT field significantly. This R2 has a sharp drop in response to this large destruction. The normalization images of IRT field, including the row and column normalization images, were proposed as auxiliary means to analyze the IRT field. The row and column normalization images respectively show the transverse and longitudinal distribution of the IRT field, and they have clear responses to the destruction occurring on the sample surface. In this paper, the new methods and quantitative index were proposed for the analysis of IRT field, which have some theoretical and instructive significance for the analysis of the characteristics of IRT field, as well as the monitoring of instability and failure for concrete structure.

Extending LMS to Support IRT-Based Assessment Test Calibration

NASA Astrophysics Data System (ADS)

Fotaris, Panagiotis; Mastoras, Theodoros; Mavridis, Ioannis; Manitsaris, Athanasios

Developing unambiguous and challenging assessment material for measuring educational attainment is a time-consuming, labor-intensive process. As a result Computer Aided Assessment (CAA) tools are becoming widely adopted in academic environments in an effort to improve the assessment quality and deliver reliable results of examinee performance. This paper introduces a methodological and architectural framework which embeds a CAA tool in a Learning Management System (LMS) so as to assist test developers in refining items to constitute assessment tests. An Item Response Theory (IRT) based analysis is applied to a dynamic assessment profile provided by the LMS. Test developers define a set of validity rules for the statistical indices given by the IRT analysis. By applying those rules, the LMS can detect items with various discrepancies which are then flagged for review of their content. Repeatedly executing the aforementioned procedure can improve the overall efficiency of the testing process.

Weighting Test Samples in IRT Linking and Equating: Toward an Improved Sampling Design for Complex Equating. Research Report. ETS RR-13-39

ERIC Educational Resources Information Center

Qian, Jiahe; Jiang, Yanming; von Davier, Alina A.

2013-01-01

Several factors could cause variability in item response theory (IRT) linking and equating procedures, such as the variability across examinee samples and/or test items, seasonality, regional differences, native language diversity, gender, and other demographic variables. Hence, the following question arises: Is it possible to select optimal…

Applying Item Response Theory to the Development of a Screening Adaptation of the Goldman-Fristoe Test of Articulation-Second Edition

ERIC Educational Resources Information Center

Brackenbury, Tim; Zickar, Michael J.; Munson, Benjamin; Storkel, Holly L.

2017-01-01

Purpose: Item response theory (IRT) is a psychometric approach to measurement that uses latent trait abilities (e.g., speech sound production skills) to model performance on individual items that vary by difficulty and discrimination. An IRT analysis was applied to preschoolers' productions of the words on the Goldman-Fristoe Test of…

Comparing five depression measures in depressed Chinese patients using item response theory: an examination of item properties, measurement precision and score comparability.

PubMed

Zhao, Yue; Chan, Wai; Lo, Barbara Chuen Yee

2017-04-04

Item response theory (IRT) has been increasingly applied to patient-reported outcome (PRO) measures. The purpose of this study is to apply IRT to examine item properties (discrimination and severity of depressive symptoms), measurement precision and score comparability across five depression measures, which is the first study of its kind in the Chinese context. A clinical sample of 207 Hong Kong Chinese outpatients was recruited. Data analyses were performed including classical item analysis, IRT concurrent calibration and IRT true score equating. The IRT assumptions of unidimensionality and local independence were tested respectively using confirmatory factor analysis and chi-square statistics. The IRT linking assumptions of construct similarity, equity and subgroup invariance were also tested. The graded response model was applied to concurrently calibrate all five depression measures in a single IRT run, resulting in the item parameter estimates of these measures being placed onto a single common metric. IRT true score equating was implemented to perform the outcome score linking and construct score concordances so as to link scores from one measure to corresponding scores on another measure for direct comparability. Findings suggested that (a) symptoms on depressed mood, suicidality and feeling of worthlessness served as the strongest discriminating indicators, and symptoms concerning suicidality, changes in appetite, depressed mood, feeling of worthlessness and psychomotor agitation or retardation reflected high levels of severity in the clinical sample. (b) The five depression measures contributed to various degrees of measurement precision at varied levels of depression. (c) After outcome score linking was performed across the five measures, the cut-off scores led to either consistent or discrepant diagnoses for depression. The study provides additional evidence regarding the psychometric properties and clinical utility of the five depression measures, offers methodological contributions to the appropriate use of IRT in PRO measures, and helps elucidate cultural variation in depressive symptomatology. The approach of concurrently calibrating and linking multiple PRO measures can be applied to the assessment of PROs other than the depression context.

Diagnosing cystic fibrosis in newborn screening in Poland - 15 years of experience.

PubMed

Sands, Dorota; Zybert, Katarzyna; Mierzejewska, Ewa; Ołtarzewski, Mariusz

2015-01-01

Early diagnosis of cystic fibrosis (CF) made by the introduction of CF NBS (Cystic Fibrosis Newborn Screening) provides the opportunity to undertake preventive measures and provide treatment before the development of irreversible changes in the respiratory tract and other complications. CF NBS was conducted as a pilot programme in four Polish districts in the period 1999-2003. In 2006 CF NBS started again and was gradually extended across the country. The aim of this study was to show the evolution of the Polish CF NBS strategies and assess the diagnostic consequences of this programme. The study involved children diagnosed and treated only in the IMiD Centre. The strategy in Polish CF NBS was modified over time. Firstly, the model IRT/IRT and IRT/IRT/DNA with one mutation was implemented, which was followed by IRT/DNA with a gradually expanding number of CFTR mutations (tab. I). Newborns with positive results of CF NBS were called to the CF IMiD Centre, and sweat tests were performed. The children diagnosed and children with mutations in both alleles of the CFTR gene even if at least one of them had undefined pathogenicity) were taken under IMiD Centre care. Sensitivity, specificity and positive predictive values during subsequent stages of CF NBS were calculated (tab. III). During the 1999-2003 pilot study 444 063 newborns underwent CF NBS and in 74 cases CF was diagnosed. 582 693 newborns were screened from September 2006 to December 2011 in four regions and 100 children were diagnosed with CF. The frequencies of CF in the Polish population in both screening periods were 1:5767 and 1:5712 respectively. Firstly, the IRT/IRT model was implemented, but the number of newborns called to the CF Centre was high - the PPV was 7.6%. In the next step CF NBS DNA analysis was used. Here sensitivity and specificity were high - nearly 100%. In the following years the number of mutations detected was expanded (including 16 most common ones in the Polish population). Due to the panel changes, the number of calls declined and the PPV (predictive positive value) improved (to 26.1%) after the application of expanded genetic analysis. Expanding the panel of mutations resulted in an increased number of carriers and observational subjects. IRT/DNA strategy with expanded DNA analysis provides the opportunity for earlier CF diagnosis even in children with normal sweat test values. However, this model caused frequent carrier detection and inconclusive diagnosis in comparison to IRT/IRT or IRT/IRT/DNA with a limited number of mutations. Further research and changes in Polish CF NBS are needed to increase the PPV, while preserving high sensitivity and specificity..

Validity of the 30-15 Intermittent Fitness Test in Subelite Female Athletes.

PubMed

Bruce, Lyndell M; Moule, Simon J

2017-11-01

Bruce, LM and Moule, SJ. Validity of the 30-15 intermittent fitness test in subelite female athletes. J Strength Cond Res 31(11): 3077-3082, 2017-The purpose of this study was to assess the suitability of the 30-15 Intermittent Fitness Test (IFT) as a test in netball using female athletes. Twenty-six female subelite netballers (mean age = 19.7 ± 4.6 years, mean height = 176.0 ± 6.1 cm, mean body mass = 69.7 ± 9.3 kg) completed the yo-yo intermittent recovery test level 1 (yo-yo IRT1) and the 30-15 IFT. Participants performed both assessments 1 week apart before the intervention and both tests 1 week apart after the training intervention (for a total of 4 testing sessions). A 6-week training intervention occurred between the test occasions. Pearson's correlations revealed significant very strong relationships between the 30-15 IFT and yo-yo IRT on both test occasions (test occasion 1: r = 0.71, p = 0.003 [95% confidence interval {CI} 0.35-0.89], magnitude of effect, most likely; test occasion 2: r = 0.72, p = 0.001 [95% CI: 0.42-0.88], magnitude of effect, most likely). Repeated-measures analysis of variances examining the effect of position on performance changes revealed main effects for test occasion and a position × test occasion interaction for both the 30-15 IFT and the yo-yo IRT1 (30-15 IFT: test occasion [F(1,14) = 28.68, p = 0.001, ηp = 0.67], position × test occasion interaction [F(2,14) = 9.38, p = 0.003, ηp = 0.57]; yo-yo IRT1: test occasion [F(1,15) = 11.72, p = 0.004, ηp = 0.44], position × test occasion interaction [F(2,15) = 9.96, p = 0.002, ηp = 0.57]). Results show that the 30-15 IFT is a suitable test for female netballers as it was able to detect improvements in performance after a training intervention, in addition to having a very strong significant relationship with the yo-yo IRT1.

Analysis Test of Understanding of Vectors with the Three-Parameter Logistic Model of Item Response Theory and Item Response Curves Technique

ERIC Educational Resources Information Center

Rakkapao, Suttida; Prasitpong, Singha; Arayathanitkul, Kwan

2016-01-01

This study investigated the multiple-choice test of understanding of vectors (TUV), by applying item response theory (IRT). The difficulty, discriminatory, and guessing parameters of the TUV items were fit with the three-parameter logistic model of IRT, using the parscale program. The TUV ability is an ability parameter, here estimated assuming…

DIF Testing with an Empirical-Histogram Approximation of the Latent Density for Each Group

ERIC Educational Resources Information Center

Woods, Carol M.

2011-01-01

This research introduces, illustrates, and tests a variation of IRT-LR-DIF, called EH-DIF-2, in which the latent density for each group is estimated simultaneously with the item parameters as an empirical histogram (EH). IRT-LR-DIF is used to evaluate the degree to which items have different measurement properties for one group of people versus…

A Note on Stochastic Ordering of the Latent Trait Using the Sum of Polytomous Item Scores

ERIC Educational Resources Information Center

van der Ark, L. Andries; Bergsma, Wicher P.

2010-01-01

In contrast to dichotomous item response theory (IRT) models, most well-known polytomous IRT models do not imply stochastic ordering of the latent trait by the total test score (SOL). This has been thought to make the ordering of respondents on the latent trait using the total test score questionable and throws doubt on the justifiability of using…

An Information-Correction Method for Testlet-Based Test Analysis: From the Perspectives of Item Response Theory and Generalizability Theory. Research Report. ETS RR-17-27

ERIC Educational Resources Information Center

Li, Feifei

2017-01-01

An information-correction method for testlet-based tests is introduced. This method takes advantage of both generalizability theory (GT) and item response theory (IRT). The measurement error for the examinee proficiency parameter is often underestimated when a unidimensional conditional-independence IRT model is specified for a testlet dataset. By…

Investigating the Impact of Item Parameter Drift for Item Response Theory Models with Mixture Distributions.

PubMed

Park, Yoon Soo; Lee, Young-Sun; Xing, Kuan

2016-01-01

This study investigates the impact of item parameter drift (IPD) on parameter and ability estimation when the underlying measurement model fits a mixture distribution, thereby violating the item invariance property of unidimensional item response theory (IRT) models. An empirical study was conducted to demonstrate the occurrence of both IPD and an underlying mixture distribution using real-world data. Twenty-one trended anchor items from the 1999, 2003, and 2007 administrations of Trends in International Mathematics and Science Study (TIMSS) were analyzed using unidimensional and mixture IRT models. TIMSS treats trended anchor items as invariant over testing administrations and uses pre-calibrated item parameters based on unidimensional IRT. However, empirical results showed evidence of two latent subgroups with IPD. Results also showed changes in the distribution of examinee ability between latent classes over the three administrations. A simulation study was conducted to examine the impact of IPD on the estimation of ability and item parameters, when data have underlying mixture distributions. Simulations used data generated from a mixture IRT model and estimated using unidimensional IRT. Results showed that data reflecting IPD using mixture IRT model led to IPD in the unidimensional IRT model. Changes in the distribution of examinee ability also affected item parameters. Moreover, drift with respect to item discrimination and distribution of examinee ability affected estimates of examinee ability. These findings demonstrate the need to caution and evaluate IPD using a mixture IRT framework to understand its effects on item parameters and examinee ability.

Investigating the Impact of Item Parameter Drift for Item Response Theory Models with Mixture Distributions

PubMed Central

Park, Yoon Soo; Lee, Young-Sun; Xing, Kuan

2016-01-01

This study investigates the impact of item parameter drift (IPD) on parameter and ability estimation when the underlying measurement model fits a mixture distribution, thereby violating the item invariance property of unidimensional item response theory (IRT) models. An empirical study was conducted to demonstrate the occurrence of both IPD and an underlying mixture distribution using real-world data. Twenty-one trended anchor items from the 1999, 2003, and 2007 administrations of Trends in International Mathematics and Science Study (TIMSS) were analyzed using unidimensional and mixture IRT models. TIMSS treats trended anchor items as invariant over testing administrations and uses pre-calibrated item parameters based on unidimensional IRT. However, empirical results showed evidence of two latent subgroups with IPD. Results also showed changes in the distribution of examinee ability between latent classes over the three administrations. A simulation study was conducted to examine the impact of IPD on the estimation of ability and item parameters, when data have underlying mixture distributions. Simulations used data generated from a mixture IRT model and estimated using unidimensional IRT. Results showed that data reflecting IPD using mixture IRT model led to IPD in the unidimensional IRT model. Changes in the distribution of examinee ability also affected item parameters. Moreover, drift with respect to item discrimination and distribution of examinee ability affected estimates of examinee ability. These findings demonstrate the need to caution and evaluate IPD using a mixture IRT framework to understand its effects on item parameters and examinee ability. PMID:26941699

A new IRT-based standard setting method: application to eCat-listening.

PubMed

García, Pablo Eduardo; Abad, Francisco José; Olea, Julio; Aguado, David

2013-01-01

Criterion-referenced interpretations of tests are highly necessary, which usually involves the difficult task of establishing cut scores. Contrasting with other Item Response Theory (IRT)-based standard setting methods, a non-judgmental approach is proposed in this study, in which Item Characteristic Curve (ICC) transformations lead to the final cut scores. eCat-Listening, a computerized adaptive test for the evaluation of English Listening, was administered to 1,576 participants, and the proposed standard setting method was applied to classify them into the performance standards of the Common European Framework of Reference for Languages (CEFR). The results showed a classification closely related to relevant external measures of the English language domain, according to the CEFR. It is concluded that the proposed method is a practical and valid standard setting alternative for IRT-based tests interpretations.

Standardized assessment of infrared thermographic fever screening system performance

NASA Astrophysics Data System (ADS)

Ghassemi, Pejhman; Pfefer, Joshua; Casamento, Jon; Wang, Quanzeng

2017-03-01

Thermal modalities represent the only currently viable mass fever screening approach for outbreaks of infectious disease pandemics such as Ebola and SARS. Non-contact infrared thermometers (NCITs) and infrared thermographs (IRTs) have been previously used for mass fever screening in transportation hubs such as airports to reduce the spread of disease. While NCITs remain a more popular choice for fever screening in the field and at fixed locations, there has been increasing evidence in the literature that IRTs can provide greater accuracy in estimating core body temperature if appropriate measurement practices are applied - including the use of technically suitable thermographs. Therefore, the purpose of this study was to develop a battery of evaluation test methods for standardized, objective and quantitative assessment of thermograph performance characteristics critical to assessing suitability for clinical use. These factors include stability, drift, uniformity, minimum resolvable temperature difference, and accuracy. Two commercial IRT models were characterized. An external temperature reference source with high temperature accuracy was utilized as part of the screening thermograph. Results showed that both IRTs are relatively accurate and stable (<1% error of reading with stability of +/-0.05°C). Overall, results of this study may facilitate development of standardized consensus test methods to enable consistent and accurate use of IRTs for fever screening.

Detecting Local Item Dependence in Polytomous Adaptive Data

ERIC Educational Resources Information Center

Mislevy, Jessica L.; Rupp, Andre A.; Harring, Jeffrey R.

2012-01-01

A rapidly expanding arena for item response theory (IRT) is in attitudinal and health-outcomes survey applications, often with polytomous items. In particular, there is interest in computer adaptive testing (CAT). Meeting model assumptions is necessary to realize the benefits of IRT in this setting, however. Although initial investigations of…

Rasch Analysis for Binary Data with Nonignorable Nonresponses

ERIC Educational Resources Information Center

Bertoli-Barsotti, Lucio; Punzo, Antonio

2013-01-01

This paper introduces a two-dimensional Item Response Theory (IRT) model to deal with nonignorable nonresponses in tests with dichotomous items. One dimension provides information about the omitting behavior, while the other dimension is related to the person's "ability". The idea of embedding an IRT model for missingness into the measurement…

Invariance Properties for General Diagnostic Classification Models

ERIC Educational Resources Information Center

Bradshaw, Laine P.; Madison, Matthew J.

2016-01-01

In item response theory (IRT), the invariance property states that item parameter estimates are independent of the examinee sample, and examinee ability estimates are independent of the test items. While this property has long been established and understood by the measurement community for IRT models, the same cannot be said for diagnostic…

Biases and power for groups comparison on subjective health measurements.

PubMed

Hamel, Jean-François; Hardouin, Jean-Benoit; Le Neel, Tanguy; Kubis, Gildas; Roquelaure, Yves; Sébille, Véronique

2012-01-01

Subjective health measurements are increasingly used in clinical research, particularly for patient groups comparisons. Two main types of analytical strategies can be used for such data: so-called classical test theory (CTT), relying on observed scores and models coming from Item Response Theory (IRT) relying on a response model relating the items responses to a latent parameter, often called latent trait. Whether IRT or CTT would be the most appropriate method to compare two independent groups of patients on a patient reported outcomes measurement remains unknown and was investigated using simulations. For CTT-based analyses, groups comparison was performed using t-test on the scores. For IRT-based analyses, several methods were compared, according to whether the Rasch model was considered with random effects or with fixed effects, and the group effect was included as a covariate or not. Individual latent traits values were estimated using either a deterministic method or by stochastic approaches. Latent traits were then compared with a t-test. Finally, a two-steps method was performed to compare the latent trait distributions, and a Wald test was performed to test the group effect in the Rasch model including group covariates. The only unbiased IRT-based method was the group covariate Wald's test, performed on the random effects Rasch model. This model displayed the highest observed power, which was similar to the power using the score t-test. These results need to be extended to the case frequently encountered in practice where data are missing and possibly informative.

Ice-Accretion Scaling Using Water-Film Thickness Parameters

NASA Technical Reports Server (NTRS)

Anderson, David N.; Feo, Alejandro

2003-01-01

Studies were performed at INTA in Spain to determine water-film thickness on a stagnation-point probe inserted in a simulated cloud. The measurements were correlated with non-dimensional parameters describing the flow and the cloud conditions. Icing scaling tests in the NASA Glenn Icing Research Tunnel were then conducted using the Ruff scaling method with the scale velocity found by matching scale and reference values of either the INTA non-dimensional water-film thickness or a Weber number based on that film thickness. For comparison, tests were also performed using the constant drop-size Weber number and the average-velocity methods. The reference and scale models were both aluminum, 61-cm-span, NACA 0012 airfoil sections at 0 deg. AOA. The reference had a 53-cm-chord and the scale, 27 cm (1/2 size). Both models were mounted vertically in the center of the IRT test section. Tests covered a freezing fraction range of 0.28 to 1.0. Rime ice (n = 1.0) tests showed the consistency of the IRT calibration over a range of velocities. At a freezing fraction of 0.76, there was no significant difference in the scale ice shapes produced by the different methods. For freezing fractions of 0.40, 0.52 and 0.61, somewhat better agreement with the reference horn angles was typically achieved with the average-velocity and constant-film thickness methods than when either of the two Weber numbers was matched to the reference value. At a freezing fraction of 0.28, the four methods were judged equal in providing simulations of the reference shape.

Comparison of immunoreactive serum trypsinogen and lipase in Cystic Fibrosis

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

Lloyd-Still, J.D.; Weiss, S.; Wessel, H.

1984-01-01

The incidence of Cystic Fibrosis (CF) is 1 in 2,000. Early detection and treatment of CF may necessitate newborn screening with a reliable and cost-effective test. Serum immunoreactive trypsinogen (IRT) an enzyme produced by the pancreas, is detectable by radioimmunoassay (RIA) techniques. Recently, it has been shown that IRT is elevated in CF infants for the first few months of life and levels become subnormal as pancreatic insufficiency progresses. Other enzymes produced by the pancreas, such as lipase, are also elevated during this time. The author's earlier work confirmed previous reports of elevated IRT levels in CF infants. The developmentmore » of a new RIA for lipase (nuclipase) has enabled comparison of these 2 pancreatic enzymes in C.F. Serum IRT and lipase determinations were performed on 2 groups of CF patients; infants under 1 year of age, and children between 1 and 18 years of age. Control populations of the same age groups were included. The results showed that both trypsin (161 +- 92 ng/ml, range 20 to 400) and lipase (167 +- 151 ng/ml, range 29 to 500) are elevated in CF in the majority of infants. Control infants had values of IRT ranging from 20 to 29.5 ng/ml and lipase values ranging from 23 to 34 ng/ml. IRT becomes subnormal in most CF patients by 8 years of age as pancreatic function insufficiency increases. Lipase levels and IRT levels correlate well in infancy, but IRT is a more sensitive indicator of pancreatic insufficiency in older patients with CF.« less

Development of a Computer-Adaptive Physical Function Instrument for Social Security Administration Disability Determination

PubMed Central

Ni, Pengsheng; McDonough, Christine M.; Jette, Alan M.; Bogusz, Kara; Marfeo, Elizabeth E.; Rasch, Elizabeth K.; Brandt, Diane E.; Meterko, Mark; Chan, Leighton

2014-01-01

Objectives To develop and test an instrument to assess physical function (PF) for Social Security Administration (SSA) disability programs, the SSA-PF. Item Response Theory (IRT) analyses were used to 1) create a calibrated item bank for each of the factors identified in prior factor analyses, 2) assess the fit of the items within each scale, 3) develop separate Computer-Adaptive Test (CAT) instruments for each scale, and 4) conduct initial psychometric testing. Design Cross-sectional data collection; IRT analyses; CAT simulation. Setting Telephone and internet survey. Participants Two samples: 1,017 SSA claimants, and 999 adults from the US general population. Interventions None. Main Outcome Measure Model fit statistics, correlation and reliability coefficients, Results IRT analyses resulted in five unidimensional SSA-PF scales: Changing & Maintaining Body Position, Whole Body Mobility, Upper Body Function, Upper Extremity Fine Motor, and Wheelchair Mobility for a total of 102 items. High CAT accuracy was demonstrated by strong correlations between simulated CAT scores and those from the full item banks. Comparing the simulated CATs to the full item banks, very little loss of reliability or precision was noted, except at the lower and upper ranges of each scale. No difference in response patterns by age or sex was noted. The distributions of claimant scores were shifted to the lower end of each scale compared to those of a sample of US adults. Conclusions The SSA-PF instrument contributes important new methodology for measuring the physical function of adults applying to the SSA disability programs. Initial evaluation revealed that the SSA-PF instrument achieved considerable breadth of coverage in each content domain and demonstrated noteworthy psychometric properties. PMID:23578594

Development of a computer-adaptive physical function instrument for Social Security Administration disability determination.

PubMed

Ni, Pengsheng; McDonough, Christine M; Jette, Alan M; Bogusz, Kara; Marfeo, Elizabeth E; Rasch, Elizabeth K; Brandt, Diane E; Meterko, Mark; Haley, Stephen M; Chan, Leighton

2013-09-01

To develop and test an instrument to assess physical function for Social Security Administration (SSA) disability programs, the SSA-Physical Function (SSA-PF) instrument. Item response theory (IRT) analyses were used to (1) create a calibrated item bank for each of the factors identified in prior factor analyses, (2) assess the fit of the items within each scale, (3) develop separate computer-adaptive testing (CAT) instruments for each scale, and (4) conduct initial psychometric testing. Cross-sectional data collection; IRT analyses; CAT simulation. Telephone and Internet survey. Two samples: SSA claimants (n=1017) and adults from the U.S. general population (n=999). None. Model fit statistics, correlation, and reliability coefficients. IRT analyses resulted in 5 unidimensional SSA-PF scales: Changing & Maintaining Body Position, Whole Body Mobility, Upper Body Function, Upper Extremity Fine Motor, and Wheelchair Mobility for a total of 102 items. High CAT accuracy was demonstrated by strong correlations between simulated CAT scores and those from the full item banks. On comparing the simulated CATs with the full item banks, very little loss of reliability or precision was noted, except at the lower and upper ranges of each scale. No difference in response patterns by age or sex was noted. The distributions of claimant scores were shifted to the lower end of each scale compared with those of a sample of U.S. adults. The SSA-PF instrument contributes important new methodology for measuring the physical function of adults applying to the SSA disability programs. Initial evaluation revealed that the SSA-PF instrument achieved considerable breadth of coverage in each content domain and demonstrated noteworthy psychometric properties. Copyright © 2013 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Item response theory analysis of Centers for Disease Control and Prevention Health-Related Quality of Life (CDC HRQOL) items in adults with arthritis.

PubMed

Mielenz, Thelma J; Callahan, Leigh F; Edwards, Michael C

2016-03-12

Examine the feasibility of performing an item response theory (IRT) analysis on two of the Centers for Disease Control and Prevention health-related quality of life (CDC HRQOL) modules - the 4-item Healthy Days Core Module (HDCM) and the 5-item Healthy days Symptoms Module (HDSM). Previous principal components analyses confirm that the two scales both assess a mix of mental (CDC-MH) and physical health (CDC-PH). The purpose is to conduct item response theory (IRT) analysis on the CDC-MH and CDC-PH scales separately. 2182 patients with self-reported or physician-diagnosed arthritis completed a cross-sectional survey including HDCM and HDSM items. Besides global health, the other 8 items ask the number of days that some statement was true; we chose to recode the data into 8 categories based on observed clustering. The IRT assumptions were assessed using confirmatory factor analysis and the data could be modeled using an unidimensional IRT model. The graded response model was used for IRT analyses and CDC-MH and CDC-PH scales were analyzed separately in flexMIRT. The IRT parameter estimates for the five-item CDC-PH all appeared reasonable. The three-item CDC-MH did not have reasonable parameter estimates. The CDC-PH scale is amenable to IRT analysis but the existing The CDC-MH scale is not. We suggest either using the 4-item Healthy Days Core Module (HDCM) and the 5-item Healthy days Symptoms Module (HDSM) as they currently stand or the CDC-PH scale alone if the primary goal is to measure physical health related HRQOL.

Use of Laser Speckle Contrast Imaging to Assess Digital Microvascular Function in Primary Raynaud Phenomenon and Systemic Sclerosis: A Comparison Using the Raynaud Condition Score Diary.

PubMed

Pauling, John D; Shipley, Jacqueline A; Hart, Darren J; McGrogan, Anita; McHugh, Neil J

2015-07-01

Evaluate objective assessment of digital microvascular function using laser speckle contrast imaging (LSCI) in a cross-sectional study of patients with primary Raynaud phenomenon (RP) and systemic sclerosis (SSc), comparing LSCI with both infrared thermography (IRT) and subjective assessment using the Raynaud Condition Score (RCS) diary. Patients with SSc (n = 25) and primary RP (n = 18) underwent simultaneous assessment of digital perfusion using LSCI and IRT with a cold challenge on 2 occasions, 2 weeks apart. The RCS diary was completed between assessments. The relationship between objective and subjective assessments of RP was evaluated. Reproducibility of LSCI/IRT was assessed, along with differences between primary RP and SSc, and the effect of sex. There was moderate-to-good correlation between LSCI and IRT (Spearman rho 0.58-0.84, p < 0.01), but poor correlation between objective assessments and the RCS diary (p > 0.05 for all analyses). Reproducibility of IRT and LSCI was moderate at baseline (ICC 0.51-0.63) and immediately following cold challenge (ICC 0.56-0.86), but lower during reperfusion (ICC 0.3-0.7). Neither subjective nor objective assessments differentiated between primary RP and SSc. Men reported lower median daily frequency of RP attacks (0.82 vs 1.93, p = 0.03). Perfusion using LSCI/IRT was higher in men for the majority of assessments. Objective and subjective methods provide differing information on microvascular function in RP. There is good convergent validity of LSCI with IRT and acceptable reproducibility of both modalities. Neither subjective nor objective assessments could differentiate between primary RP and SSc. Influence of sex on subjective and objective assessment of RP warrants further evaluation.

Effectiveness of Item Response Theory (IRT) Proficiency Estimation Methods under Adaptive Multistage Testing. Research Report. ETS RR-15-11

ERIC Educational Resources Information Center

Kim, Sooyeon; Moses, Tim; Yoo, Hanwook Henry

2015-01-01

The purpose of this inquiry was to investigate the effectiveness of item response theory (IRT) proficiency estimators in terms of estimation bias and error under multistage testing (MST). We chose a 2-stage MST design in which 1 adaptation to the examinees' ability levels takes place. It includes 4 modules (1 at Stage 1, 3 at Stage 2) and 3 paths…

A Review of the Effects on IRT Item Parameter Estimates with a Focus on Misbehaving Common Items in Test Equating

PubMed Central

Michaelides, Michalis P.

2010-01-01

Many studies have investigated the topic of change or drift in item parameter estimates in the context of item response theory (IRT). Content effects, such as instructional variation and curricular emphasis, as well as context effects, such as the wording, position, or exposure of an item have been found to impact item parameter estimates. The issue becomes more critical when items with estimates exhibiting differential behavior across test administrations are used as common for deriving equating transformations. This paper reviews the types of effects on IRT item parameter estimates and focuses on the impact of misbehaving or aberrant common items on equating transformations. Implications relating to test validity and the judgmental nature of the decision to keep or discard aberrant common items are discussed, with recommendations for future research into more informed and formal ways of dealing with misbehaving common items. PMID:21833230

A Review of the Effects on IRT Item Parameter Estimates with a Focus on Misbehaving Common Items in Test Equating.

PubMed

Michaelides, Michalis P

2010-01-01

Many studies have investigated the topic of change or drift in item parameter estimates in the context of item response theory (IRT). Content effects, such as instructional variation and curricular emphasis, as well as context effects, such as the wording, position, or exposure of an item have been found to impact item parameter estimates. The issue becomes more critical when items with estimates exhibiting differential behavior across test administrations are used as common for deriving equating transformations. This paper reviews the types of effects on IRT item parameter estimates and focuses on the impact of misbehaving or aberrant common items on equating transformations. Implications relating to test validity and the judgmental nature of the decision to keep or discard aberrant common items are discussed, with recommendations for future research into more informed and formal ways of dealing with misbehaving common items.

An Extension of IRT-Based Equating to the Dichotomous Testlet Response Theory Model

ERIC Educational Resources Information Center

Tao, Wei; Cao, Yi

2016-01-01

Current procedures for equating number-correct scores using traditional item response theory (IRT) methods assume local independence. However, when tests are constructed using testlets, one concern is the violation of the local item independence assumption. The testlet response theory (TRT) model is one way to accommodate local item dependence.…

IRT Model Selection Methods for Dichotomous Items

ERIC Educational Resources Information Center

Kang, Taehoon; Cohen, Allan S.

2007-01-01

Fit of the model to the data is important if the benefits of item response theory (IRT) are to be obtained. In this study, the authors compared model selection results using the likelihood ratio test, two information-based criteria, and two Bayesian methods. An example illustrated the potential for inconsistency in model selection depending on…

Immediate list recall as a measure of short-term episodic memory: insights from the serial position effect and item response theory.

PubMed

Gavett, Brandon E; Horwitz, Julie E

2012-03-01

The serial position effect shows that two interrelated cognitive processes underlie immediate recall of a supraspan word list. The current study used item response theory (IRT) methods to determine whether the serial position effect poses a threat to the construct validity of immediate list recall as a measure of verbal episodic memory. Archival data were obtained from a national sample of 4,212 volunteers aged 28-84 in the Midlife Development in the United States study. Telephone assessment yielded item-level data for a single immediate recall trial of the Rey Auditory Verbal Learning Test (RAVLT). Two parameter logistic IRT procedures were used to estimate item parameters and the Q(1) statistic was used to evaluate item fit. A two-dimensional model better fit the data than a unidimensional model, supporting the notion that list recall is influenced by two underlying cognitive processes. IRT analyses revealed that 4 of the 15 RAVLT items (1, 12, 14, and 15) were misfit (p < .05). Item characteristic curves for items 14 and 15 decreased monotonically, implying an inverse relationship between the ability level and the probability of recall. Elimination of the four misfit items provided better fit to the data and met necessary IRT assumptions. Performance on a supraspan list learning test is influenced by multiple cognitive abilities; failure to account for the serial position of words decreases the construct validity of the test as a measure of episodic memory and may provide misleading results. IRT methods can ameliorate these problems and improve construct validity.

Biases and Power for Groups Comparison on Subjective Health Measurements

PubMed Central

Hamel, Jean-François; Hardouin, Jean-Benoit; Le Neel, Tanguy; Kubis, Gildas; Roquelaure, Yves; Sébille, Véronique

2012-01-01

Subjective health measurements are increasingly used in clinical research, particularly for patient groups comparisons. Two main types of analytical strategies can be used for such data: so-called classical test theory (CTT), relying on observed scores and models coming from Item Response Theory (IRT) relying on a response model relating the items responses to a latent parameter, often called latent trait. Whether IRT or CTT would be the most appropriate method to compare two independent groups of patients on a patient reported outcomes measurement remains unknown and was investigated using simulations. For CTT-based analyses, groups comparison was performed using t-test on the scores. For IRT-based analyses, several methods were compared, according to whether the Rasch model was considered with random effects or with fixed effects, and the group effect was included as a covariate or not. Individual latent traits values were estimated using either a deterministic method or by stochastic approaches. Latent traits were then compared with a t-test. Finally, a two-steps method was performed to compare the latent trait distributions, and a Wald test was performed to test the group effect in the Rasch model including group covariates. The only unbiased IRT-based method was the group covariate Wald’s test, performed on the random effects Rasch model. This model displayed the highest observed power, which was similar to the power using the score t-test. These results need to be extended to the case frequently encountered in practice where data are missing and possibly informative. PMID:23115620

The e-MSWS-12: improving the multiple sclerosis walking scale using item response theory.

PubMed

Engelhard, Matthew M; Schmidt, Karen M; Engel, Casey E; Brenton, J Nicholas; Patek, Stephen D; Goldman, Myla D

2016-12-01

The Multiple Sclerosis Walking Scale (MSWS-12) is the predominant patient-reported measure of multiple sclerosis (MS) -elated walking ability, yet it had not been analyzed using item response theory (IRT), the emerging standard for patient-reported outcome (PRO) validation. This study aims to reduce MSWS-12 measurement error and facilitate computerized adaptive testing by creating an IRT model of the MSWS-12 and distributing it online. MSWS-12 responses from 284 subjects with MS were collected by mail and used to fit and compare several IRT models. Following model selection and assessment, subpopulations based on age and sex were tested for differential item functioning (DIF). Model comparison favored a one-dimensional graded response model (GRM). This model met fit criteria and explained 87 % of response variance. The performance of each MSWS-12 item was characterized using category response curves (CRCs) and item information. IRT-based MSWS-12 scores correlated with traditional MSWS-12 scores (r = 0.99) and timed 25-foot walk (T25FW) speed (r =  -0.70). Item 2 showed DIF based on age (χ 2  = 19.02, df = 5, p < 0.01), and Item 11 showed DIF based on sex (χ 2  = 13.76, df = 5, p = 0.02). MSWS-12 measurement error depends on walking ability, but could be lowered by improving or replacing items with low information or DIF. The e-MSWS-12 includes IRT-based scoring, error checking, and an estimated T25FW derived from MSWS-12 responses. It is available at https://ms-irt.shinyapps.io/e-MSWS-12 .

Evaluating the validity of the Work Role Functioning Questionnaire (Canadian French version) using classical test theory and item response theory.

PubMed

Hong, Quan Nha; Coutu, Marie-France; Berbiche, Djamal

2017-01-01

The Work Role Functioning Questionnaire (WRFQ) was developed to assess workers' perceived ability to perform job demands and is used to monitor presenteeism. Still few studies on its validity can be found in the literature. The purpose of this study was to assess the items and factorial composition of the Canadian French version of the WRFQ (WRFQ-CF). Two measurement approaches were used to test the WRFQ-CF: Classical Test Theory (CTT) and non-parametric Item Response Theory (IRT). A total of 352 completed questionnaires were analyzed. A four-factor and three-factor model models were tested and shown respectively good fit with 14 items (Root Mean Square Error of Approximation (RMSEA) = 0.06, Standardized Root Mean Square Residual (SRMR) = 0.04, Bentler Comparative Fit Index (CFI) = 0.98) and with 17 items (RMSEA = 0.059, SRMR = 0.048, CFI = 0.98). Using IRT, 13 problematic items were identified, of which 9 were common with CTT. This study tested different models with fewer problematic items found in a three-factor model. Using a non-parametric IRT and CTT for item purification gave complementary results. IRT is still scarcely used and can be an interesting alternative method to enhance the quality of a measurement instrument. More studies are needed on the WRFQ-CF to refine its items and factorial composition.

Linking Parameters Estimated with the Generalized Graded Unfolding Model: A Comparison of the Accuracy of Characteristic Curve Methods

ERIC Educational Resources Information Center

Anderson Koenig, Judith; Roberts, James S.

2007-01-01

Methods for linking item response theory (IRT) parameters are developed for attitude questionnaire responses calibrated with the generalized graded unfolding model (GGUM). One class of IRT linking methods derives the linking coefficients by comparing characteristic curves, and three of these methods---test characteristic curve (TCC), item…

Evaluation of the IRT Parameter Invariance Property for the MCAT.

ERIC Educational Resources Information Center

Kelkar, Vinaya; Wightman, Linda F.; Luecht, Richard M.

The purpose of this study was to investigate the viability of the property of parameter invariance for the one-parameter (1P), two-parameter (2P), and three-parameter (3P) item response theory (IRT) models for the Medical College Admissions Tests (MCAT). Invariance of item parameters across different gender, ethnic, and language groups and the…

IRT-LR-DIF with Estimation of the Focal-Group Density as an Empirical Histogram

ERIC Educational Resources Information Center

Woods, Carol M.

2008-01-01

Item response theory-likelihood ratio-differential item functioning (IRT-LR-DIF) is used to evaluate the degree to which items on a test or questionnaire have different measurement properties for one group of people versus another, irrespective of group-mean differences on the construct. Usually, the latent distribution is presumed normal for both…

A Comparison between Linear IRT Observed-Score Equating and Levine Observed-Score Equating under the Generalized Kernel Equating Framework

ERIC Educational Resources Information Center

Chen, Haiwen

2012-01-01

In this article, linear item response theory (IRT) observed-score equating is compared under a generalized kernel equating framework with Levine observed-score equating for nonequivalent groups with anchor test design. Interestingly, these two equating methods are closely related despite being based on different methodologies. Specifically, when…

An Estimation Procedure for the Structural Parameters of the Unified Cognitive/IRT Model.

ERIC Educational Resources Information Center

Jiang, Hai; And Others

L. V. DiBello, W. F. Stout, and L. A. Roussos (1993) have developed a new item response model, the Unified Model, which brings together the discrete, deterministic aspects of cognition favored by cognitive scientists, and the continuous, stochastic aspects of test response behavior that underlie item response theory (IRT). The Unified Model blends…

A Comparison of General Diagnostic Models (GDM) and Bayesian Networks Using a Middle School Mathematics Test

ERIC Educational Resources Information Center

Wu, Haiyan

2013-01-01

General diagnostic models (GDMs) and Bayesian networks are mathematical frameworks that cover a wide variety of psychometric models. Both extend latent class models, and while GDMs also extend item response theory (IRT) models, Bayesian networks can be parameterized using discretized IRT. The purpose of this study is to examine similarities and…

Assessing the Item Response Theory with Covariate (IRT-C) Procedure for Ascertaining Differential Item Functioning

ERIC Educational Resources Information Center

Tay, Louis; Vermunt, Jeroen K.; Wang, Chun

2013-01-01

We evaluate the item response theory with covariates (IRT-C) procedure for assessing differential item functioning (DIF) without preknowledge of anchor items (Tay, Newman, & Vermunt, 2011). This procedure begins with a fully constrained baseline model, and candidate items are tested for uniform and/or nonuniform DIF using the Wald statistic.…

Wind tunnel evaluation of air-foil performance using simulated ice shapes

NASA Technical Reports Server (NTRS)

Bragg, M. B.; Zaguli, R. J.; Gregorek, G. M.

1982-01-01

A two-phase wind tunnel test was conducted in the 6 by 9 foot Icing Research Tunnel (IRT) at NASA Lewis Research Center to evaluate the effect of ice on the performance of a full scale general aviation wing. In the first IRT tests, rime and glaze shapes were carefully documented as functions of angle of attack and free stream conditions. Next, simulated ice shapes were constructed for two rime and two glaze shapes and used in the second IRT tunnel entry. The ice shapes and the clean airfoil were tapped to obtain surface pressures and a probe used to measure the wake characteristics. These data were recorded and processed, on-line, with a minicomputer/digital data acquisition system. The effect of both rime and glaze ice on the pressure distribution, Cl, Cd, and Cm are presented.

New tests of the common calibration context for ISO, IRTS, and MSX

NASA Technical Reports Server (NTRS)

Cohen, Martin

1997-01-01

The work carried out in order to test, verify and validate the accuracy of the calibration spectra provided to the Infrared Space Observatory (ISO), to the Infrared Telescope in Space (IRTS) and to the Midcourse Space Experiment (MSX) for external calibration support of instruments, is reviewed. The techniques, used to vindicate the accuracy of the absolute spectra, are discussed. The work planned for comparing far infrared spectra of Mars and some of the bright stellar calibrators with long wavelength spectrometer data are summarized.

A Review of PROC IRT in SAS

ERIC Educational Resources Information Center

Choi, Jinnie

2017-01-01

This article reviews PROC IRT, which was added to Statistical Analysis Software in 2014. We provide an introductory overview of a free version of SAS, describe what PROC IRT offers for item response theory (IRT) analysis and how one can use PROC IRT, and discuss how other SAS macros and procedures may compensate the IRT functionalities of PROC IRT.

Adjusting for Year to Year Rater Variation in IRT Linking--An Empirical Evaluation

ERIC Educational Resources Information Center

Yen, Shu Jing; Ochieng, Charles; Michaels, Hillary; Friedman, Greg

2005-01-01

The main purpose of this study was to illustrate a polytomous IRT-based linking procedure that adjusts for rater variations. Test scores from two administrations of a statewide reading assessment were used. An anchor set of Year 1 students' constructed responses were rescored by Year 2 raters. To adjust for year-to-year rater variation in IRT…

Item Response Theory with Covariates (IRT-C): Assessing Item Recovery and Differential Item Functioning for the Three-Parameter Logistic Model

ERIC Educational Resources Information Center

Tay, Louis; Huang, Qiming; Vermunt, Jeroen K.

2016-01-01

In large-scale testing, the use of multigroup approaches is limited for assessing differential item functioning (DIF) across multiple variables as DIF is examined for each variable separately. In contrast, the item response theory with covariate (IRT-C) procedure can be used to examine DIF across multiple variables (covariates) simultaneously. To…

Fitting a Mixture Item Response Theory Model to Personality Questionnaire Data: Characterizing Latent Classes and Investigating Possibilities for Improving Prediction

ERIC Educational Resources Information Center

Maij-de Meij, Annette M.; Kelderman, Henk; van der Flier, Henk

2008-01-01

Mixture item response theory (IRT) models aid the interpretation of response behavior on personality tests and may provide possibilities for improving prediction. Heterogeneity in the population is modeled by identifying homogeneous subgroups that conform to different measurement models. In this study, mixture IRT models were applied to the…

A Primer on the 2- and 3-Parameter Item Response Theory Models.

ERIC Educational Resources Information Center

Thornton, Artist

Item response theory (IRT) is a useful and effective tool for item response measurement if used in the proper context. This paper discusses the sets of assumptions under which responses can be modeled while exploring the framework of the IRT models relative to response testing. The one parameter model, or one parameter logistic model, is perhaps…

Accuracy and Variability of Item Parameter Estimates from Marginal Maximum a Posteriori Estimation and Bayesian Inference via Gibbs Samplers

ERIC Educational Resources Information Center

Wu, Yi-Fang

2015-01-01

Item response theory (IRT) uses a family of statistical models for estimating stable characteristics of items and examinees and defining how these characteristics interact in describing item and test performance. With a focus on the three-parameter logistic IRT (Birnbaum, 1968; Lord, 1980) model, the current study examines the accuracy and…

Variants in Solute Carrier SLC26A9 Modify Prenatal Exocrine Pancreatic Damage in Cystic Fibrosis

PubMed Central

Miller, Melissa R.; Soave, David; Li, Weili; Gong, Jiafen; Pace, Rhonda G.; Boëlle, Pierre-Yves; Cutting, Garry R.; Drumm, Mitchell L.; Knowles, Michael R.; Sun, Lei; Rommens, Johanna M.; Accurso, Frank; Durie, Peter R.; Corvol, Harriet; Levy, Hara; Sontag, Marci K.; Strug, Lisa J.

2015-01-01

Objectives To test the hypothesis that multiple constituents of the apical plasma membrane residing alongside the causal CF Transmembrane Conductance Regulator (CFTR) protein, including known cystic fibrosis (CF) modifiers SLC26A9, SLC6A14, and SLC9A3, would be associated with prenatal exocrine pancreatic damage as measured by newborn screened (NBS) IRT levels. Study design NBS IRT measures and genome-wide genotype data were available on 111 subjects from Colorado, 37 subjects from Wisconsin, and 80 subjects from France. Multiple linear regression was used to determine whether any of eight SNPs in SLC26A9, SLC6A14 and SLC9A3 were associated with IRT and whether other constituents of the apical plasma membrane contributed to IRT. Results In the Colorado sample, three SLC26A9 SNPs were associated with NBS IRT (min P = 1.16 × 10−3; rs7512462), but no SLC6A14 or SLC9A3 SNPs were associated (P > 0.05). The rs7512462 association replicated in the Wisconsin sample (P = 0.03) but not in the French sample (P = 0.76). Furthermore, rs7512462 was the top ranked apical membrane constituent in the combined Colorado and Wisconsin sample. Conclusions NBS IRT is a biomarker of prenatal exocrine pancreatic disease in patients with CF, and a SNP in SLC26A9 accounts for significant IRT variability. This suggests SLC26A9 as a potential therapeutic target to ameliorate exocrine pancreatic disease. PMID:25771386

The Robustness of LOGIST and BILOG IRT Estimation Programs to Violations of Local Independence.

ERIC Educational Resources Information Center

Ackerman, Terry A.

One of the important underlying assumptions of all item response theory (IRT) models is that of local independence. This assumption requires that the response to an item on a test not be influenced by the response to any other items. This assumption is often taken for granted, with little or no scrutiny of the response process required to answer…

A Comparison of the One-, the Modified Three-, and the Three-Parameter Item Response Theory Models in the Test Development Item Selection Process.

ERIC Educational Resources Information Center

Eignor, Daniel R.; Douglass, James B.

This paper attempts to provide some initial information about the use of a variety of item response theory (IRT) models in the item selection process; its purpose is to compare the information curves derived from the selection of items characterized by several different IRT models and their associated parameter estimation programs. These…

Screening for fever by remote-sensing infrared thermographic camera.

PubMed

Chan, Lung-Sang; Cheung, Giselle T Y; Lauder, Ian J; Kumana, Cyrus R; Lauder, Ian J

2004-01-01

Following the severe acute respiratory syndrome (SARS) outbreak, remote-sensing infrared thermography (IRT) has been advocated as a possible means of screening for fever in travelers at airports and border crossings, but its applicability has not been established. We therefore set out to evaluate (1) the feasibility of IRT imaging to identify subjects with fever, and (2) the optimal instrumental configuration and validity for such testing. Over a 20-day inclusive period, 176 subjects (49 hospital inpatients without SARS or suspected SARS, 99 health clinic attendees and 28 healthy volunteers) were recruited. Remotely sensed IRT readings were obtained from various parts of the front and side of the face (at distances of 1.5 and 0.5 m), and compared to concurrently determined body temperature measurements using conventional means (aural tympanic IRT and oral mercury thermometry). The resulting data were submitted to linear regression/correlation and sensitivity analyses. All recruits gave prior informed consent and our Faculty Institutional Review Board approved the protocol. Optimal correlations were found between conventionally measured body temperatures and IRT readings from (1) the front of the face at 1.5m with the mouth open (r=0.80), (2) the ear at 0.5 m (r=0.79), and (3) the side of the face at 1.5m (r=0.76). Average IRT readings from the forehead and elsewhere were 1 degrees C to 2 degrees C lower and correlated less well. Ear IRT readings at 0.5 m yielded the narrowest confidence intervals and could be used to predict conventional body temperature readings of < or = 38 degrees C with a sensitivity and specificity of 83% and 88% respectively. IRT readings from the side of the face, especially from the ear at 0.5 m, yielded the most reliable, precise and consistent estimates of conventionally determined body temperatures. Our results have important implications for walk-through IRT scanning/screening systems at airports and border crossings, particularly as the point prevalence of fever in such subjects would be very low.

Overview of classical test theory and item response theory for the quantitative assessment of items in developing patient-reported outcomes measures.

PubMed

Cappelleri, Joseph C; Jason Lundy, J; Hays, Ron D

2014-05-01

The US Food and Drug Administration's guidance for industry document on patient-reported outcomes (PRO) defines content validity as "the extent to which the instrument measures the concept of interest" (FDA, 2009, p. 12). According to Strauss and Smith (2009), construct validity "is now generally viewed as a unifying form of validity for psychological measurements, subsuming both content and criterion validity" (p. 7). Hence, both qualitative and quantitative information are essential in evaluating the validity of measures. We review classical test theory and item response theory (IRT) approaches to evaluating PRO measures, including frequency of responses to each category of the items in a multi-item scale, the distribution of scale scores, floor and ceiling effects, the relationship between item response options and the total score, and the extent to which hypothesized "difficulty" (severity) order of items is represented by observed responses. If a researcher has few qualitative data and wants to get preliminary information about the content validity of the instrument, then descriptive assessments using classical test theory should be the first step. As the sample size grows during subsequent stages of instrument development, confidence in the numerical estimates from Rasch and other IRT models (as well as those of classical test theory) would also grow. Classical test theory and IRT can be useful in providing a quantitative assessment of items and scales during the content-validity phase of PRO-measure development. Depending on the particular type of measure and the specific circumstances, the classical test theory and/or the IRT should be considered to help maximize the content validity of PRO measures. Copyright © 2014 Elsevier HS Journals, Inc. All rights reserved.

An Exploratory Analysis of Functional Staging Using an Item Response Theory Approach

PubMed Central

Tao, Wei; Haley, Stephen M.; Coster, Wendy J.; Ni, Pengsheng; Jette, Alan M.

2009-01-01

Objectives To develop and explore the feasibility of a functional staging system (defined as the process of assigning subjects, according to predetermined standards, into a set of hierarchical levels with regard to their functioning performance in mobility, daily activities, and cognitive skills) based on item response theory (IRT) methods using short-forms of the Activity Measure for Post-Acute Care (AM-PAC); and to compare the criterion validity and sensitivity of the IRT-based staging system to a non-IRT-based staging system developed for the FIM instrument. Design Prospective, longitudinal cohort study of patients interviewed at hospital discharge and 1, 6, and 12 months after inpatient rehabilitation. Setting Follow-up interviews conducted in patients’ homes. Participants Convenience sample of 516 patients (47% men; sample mean age, 68.3y) at baseline (retention at the final follow-up, 65%) with neurologic, lower-extremity orthopedic, or complex medical conditions. Interventions Not applicable Main Outcome Measures AM-PAC basic mobility, daily activity, and applied cognitive activity stages; FIM executive control, mobility, activities of daily living, and sphincter stages. Stages refer to the hierarchical levels assigned to patient’s functioning performance. Results We were able to define IRT-based staging definitions and create meaningful cut scores based on the 3 AM-PAC short-forms. The IRT stages correlated as well or better to the criterion items than the FIM stages. Both the IRT-based stages and the FIM stages were sensitive to changes throughout the 6-month follow-up period. The FIM stages were more sensitive in detecting changes between baseline and 1-month follow-up visit. The AM-PAC stages were more discriminant in the follow-up visits. Conclusions An IRT-based staging approach appeared feasible and effective in classifying patients throughout long-term follow-up. Although these stages were developed from short-forms, this staging methodology could also be applied to improve the meaning of scores generated from IRT-based computerized adaptive testing in future work. PMID:18503798

Development and evaluation of the PI-G: a three-scale measure based on the German translation of the PROMIS ® pain interference item bank.

PubMed

Farin, Erik; Nagl, Michaela; Gramm, Lukas; Heyduck, Katja; Glattacker, Manuela

2014-05-01

Study aim was to translate the PROMIS(®) pain interference (PI) item bank (41 items) into German, test its psychometric properties in patients with chronic low back pain and develop static subforms. We surveyed N = 262 patients undergoing rehabilitation who were asked to fill out questionnaires at the beginning and 2 weeks after the end of rehabilitation, applying the Oswestry Disability Index (ODI) and Pain Disability Index (PDI) in addition to the PROMIS(®) PI items. For psychometric testing, a 1-parameter item response theory (IRT) model was used. Exploratory and confirmatory factor analyses as well as reliability and construct validity analyses were conducted. The assumptions regarding IRT scaling of the translated PROMIS(®) PI item bank as a whole were not confirmed. However, we succeeded in devising three static subforms (PI-G scales: PI mental 13 items, PI functional 11 items, PI physical 4 items), revealing good psychometric properties. The PI-G scales in their static form can be recommended for use in German-speaking countries. Their strengths versus the ODI and PDI are that pain interference is assessed in a differentiated manner and that several psychometric values are somewhat better than those associated with the ODI and PDI (distribution properties, IRT model fit, reliability). To develop an IRT-scaled item bank of the German translations of the PROMIS(®) PI items, it would be useful to have additional studies (e.g., with larger sample sizes and using a 2-parameter IRT model).

An Introduction to Item Response Theory for Patient-Reported Outcome Measurement

PubMed Central

Nguyen, Tam H.; Han, Hae-Ra; Kim, Miyong T.

2015-01-01

The growing emphasis on patient-centered care has accelerated the demand for high-quality data from patient-reported outcome (PRO) measures. Traditionally, the development and validation of these measures has been guided by classical test theory. However, item response theory (IRT), an alternate measurement framework, offers promise for addressing practical measurement problems found in health-related research that have been difficult to solve through classical methods. This paper introduces foundational concepts in IRT, as well as commonly used models and their assumptions. Existing data on a combined sample (n = 636) of Korean American and Vietnamese American adults who responded to the High Blood Pressure Health Literacy Scale and the Patient Health Questionnaire-9 are used to exemplify typical applications of IRT. These examples illustrate how IRT can be used to improve the development, refinement, and evaluation of PRO measures. Greater use of methods based on this framework can increase the accuracy and efficiency with which PROs are measured. PMID:24403095

Assessing item fit for unidimensional item response theory models using residuals from estimated item response functions.

PubMed

Haberman, Shelby J; Sinharay, Sandip; Chon, Kyong Hee

2013-07-01

Residual analysis (e.g. Hambleton & Swaminathan, Item response theory: principles and applications, Kluwer Academic, Boston, 1985; Hambleton, Swaminathan, & Rogers, Fundamentals of item response theory, Sage, Newbury Park, 1991) is a popular method to assess fit of item response theory (IRT) models. We suggest a form of residual analysis that may be applied to assess item fit for unidimensional IRT models. The residual analysis consists of a comparison of the maximum-likelihood estimate of the item characteristic curve with an alternative ratio estimate of the item characteristic curve. The large sample distribution of the residual is proved to be standardized normal when the IRT model fits the data. We compare the performance of our suggested residual to the standardized residual of Hambleton et al. (Fundamentals of item response theory, Sage, Newbury Park, 1991) in a detailed simulation study. We then calculate our suggested residuals using data from an operational test. The residuals appear to be useful in assessing the item fit for unidimensional IRT models.

An introduction to item response theory for patient-reported outcome measurement.

PubMed

Nguyen, Tam H; Han, Hae-Ra; Kim, Miyong T; Chan, Kitty S

2014-01-01

The growing emphasis on patient-centered care has accelerated the demand for high-quality data from patient-reported outcome (PRO) measures. Traditionally, the development and validation of these measures has been guided by classical test theory. However, item response theory (IRT), an alternate measurement framework, offers promise for addressing practical measurement problems found in health-related research that have been difficult to solve through classical methods. This paper introduces foundational concepts in IRT, as well as commonly used models and their assumptions. Existing data on a combined sample (n = 636) of Korean American and Vietnamese American adults who responded to the High Blood Pressure Health Literacy Scale and the Patient Health Questionnaire-9 are used to exemplify typical applications of IRT. These examples illustrate how IRT can be used to improve the development, refinement, and evaluation of PRO measures. Greater use of methods based on this framework can increase the accuracy and efficiency with which PROs are measured.

Icing Research Tunnel (IRT) Force Measurement System (FMS)

NASA Technical Reports Server (NTRS)

Roberts, Paul W.

2012-01-01

An Electronics Engineer at the Glenn Research Center (GRC), requested the NASA Engineering and Safety Center (NESC) provide technical support for an evaluation of the existing force measurement system (FMS) at the GRC's Icing Research Tunnel (IRT) with the intent of developing conceptual designs to improve the tunnel's force measurement capability in order to better meet test customer needs. This report contains the outcome of the NESC technical review.

Implementation of newborn screening for cystic fibrosis in Norway. Results from the first three years.

PubMed

Lundman, Emma; Gaup, H Junita; Bakkeheim, Egil; Olafsdottir, Edda J; Rootwelt, Terje; Storrøsten, Olav Trond; Pettersen, Rolf D

2016-05-01

Norway introduced newborn screening for cystic fibrosis (CF) March 1, 2012. We present results from the first three years of the national newborn CF screening program. Positive primary screening of immunoreactive trypsinogen (IRT) was followed by DNA testing of the Cystic fibrosis transmembrane conductance regulator (CFTR) gene. Infants with two CFTR mutations were reported for diagnostic follow-up. Of 181,859 infants tested, 1454 samples (0.80%) were assessed for CFTR mutations. Forty children (1:4546) had two CFTR mutations, of which only 21 (1:8660) were confirmed to have a CF diagnosis. The CFTR mutations differed from previously clinically diagnosed CF patients, and p.R117H outnumbered p.F508del as the most frequent mutation. One child with a negative IRT screening test was later clinically diagnosed with CF. The CF screening program identified fewer children with a conclusive CF diagnosis than expected. Our data suggest a revision of the IRT/DNA protocol. Copyright © 2016 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

Alzheimer's Disease Assessment: A Review and Illustrations Focusing on Item Response Theory Techniques.

PubMed

Balsis, Steve; Choudhury, Tabina K; Geraci, Lisa; Benge, Jared F; Patrick, Christopher J

2018-04-01

Alzheimer's disease (AD) affects neurological, cognitive, and behavioral processes. Thus, to accurately assess this disease, researchers and clinicians need to combine and incorporate data across these domains. This presents not only distinct methodological and statistical challenges but also unique opportunities for the development and advancement of psychometric techniques. In this article, we describe relatively recent research using item response theory (IRT) that has been used to make progress in assessing the disease across its various symptomatic and pathological manifestations. We focus on applications of IRT to improve scoring, test development (including cross-validation and adaptation), and linking and calibration. We conclude by describing potential future multidimensional applications of IRT techniques that may improve the precision with which AD is measured.

Comprehensive CFTR gene analysis of the French cystic fibrosis screened newborn cohort: implications for diagnosis, genetic counseling, and mutation-specific therapy.

PubMed

Audrézet, Marie Pierre; Munck, Anne; Scotet, Virginie; Claustres, Mireille; Roussey, Michel; Delmas, Dominique; Férec, Claude; Desgeorges, Marie

2015-02-01

Newborn screening (NBS) for cystic fibrosis (CF) was implemented throughout France in 2002. It involves a four-tiered procedure: immunoreactive trypsin (IRT)/DNA/IRT/sweat test [corrected] was implemented throughout France in 2002. The aim of this study was to assess the performance of molecular CFTR gene analysis from the French NBS cohort, to evaluate CF incidence, mutation detection rate, and allelic heterogeneity. During the 8-year period, 5,947,148 newborns were screened for cystic fibrosis. The data were collected by the Association Française pour le Dépistage et la Prévention des Handicaps de l'Enfant. The mutations identified were classified into four groups based on their potential for causing disease, and a diagnostic algorithm was proposed. Combining the genetic and sweat test results, 1,160 neonates were diagnosed as having cystic fibrosis. The corresponding incidence, including both the meconium ileus (MI) and false-negative cases, was calculated at 1 in 4,726 live births. The CF30 kit, completed with a comprehensive CFTR gene analysis, provides an excellent detection rate of 99.77% for the mutated alleles, enabling the identification of a complete genotype in 99.55% of affected neonates. With more than 200 different mutations characterized, we confirmed the French allelic heterogeneity. The very good sensitivity, specificity, and positive predictive value obtained suggest that the four-tiered IRT/DNA/IRT/sweat test procedure may provide an effective strategy for newborn screening for cystic fibrosis.

Clinical applications of dynamic infrared thermography in plastic surgery: a systematic review

PubMed Central

John, Hannah Eliza; Niumsawatt, Vachara; Whitaker, Iain S.

2016-01-01

Background Infrared thermography (IRT) has become an increasingly utilized adjunct to more expensive and/or invasive investigations in a range of surgical fields, no more so than in plastic surgery. The combination of functional assessment, flow characteristics and anatomical localization has led to increasing applications of this technology. This article aims to perform a systematic review of the clinical applications of IRT in plastic surgery. Methods A systematic literature search using the keywords ‘IRT’ and ‘dynamic infrared thermography (DIRT)’ has been accomplished. A total of 147 papers were extracted from various medical databases, of which 34 articles were subjected to a full read by two independent reviewers, to ensure the papers satisfied the inclusion and exclusion criteria. Studies focusing on the use of IRT in breast cancer diagnosis were excluded. Results A systematic review of 29 publications demonstrated the clinical applications of IRT in plastic surgery today. They include preoperative planning of perforators for free flaps, post operative monitoring of free flaps, use of IRT as an adjunct in burns depth analysis, in assessment of response to treatment in hemangioma and as a diagnostic test for cutaneous melanoma and carpal tunnel syndrome (CTS). Conclusions Modern infrared imaging technology with improved standardization protocols is now a credible, useful non-invasive tool in clinical practice. PMID:27047781

Gastrin: The Test

MedlinePlus

... Cancer Therapy Glucose Tests Gonorrhea Testing Gram Stain Growth Hormone Haptoglobin hCG Pregnancy hCG Tumor Marker HDL Cholesterol ... Immunoreactive Trypsinogen (IRT) Influenza Tests Insulin Insulin-like Growth Factor-1 ... Hormone (LH) Lyme Disease Tests Magnesium Maternal Serum Screening, ...

Antithrombin Test

MedlinePlus

... Cancer Therapy Glucose Tests Gonorrhea Testing Gram Stain Growth Hormone Haptoglobin hCG Pregnancy hCG Tumor Marker HDL Cholesterol ... Immunoreactive Trypsinogen (IRT) Influenza Tests Insulin Insulin-like Growth Factor-1 ... Hormone (LH) Lyme Disease Tests Magnesium Maternal Serum Screening, ...

Understanding Your Tests

MedlinePlus

... Cancer Therapy Glucose Tests Gonorrhea Testing Gram Stain Growth Hormone Haptoglobin hCG Pregnancy hCG Tumor Marker HDL Cholesterol ... Immunoreactive Trypsinogen (IRT) Influenza Tests Insulin Insulin-like Growth Factor-1 ... Hormone (LH) Lyme Disease Tests Magnesium Maternal Serum Screening, ...

Direct Antiglobulin Test

MedlinePlus

... Cancer Therapy Glucose Tests Gonorrhea Testing Gram Stain Growth Hormone Haptoglobin hCG Pregnancy hCG Tumor Marker HDL Cholesterol ... Immunoreactive Trypsinogen (IRT) Influenza Tests Insulin Insulin-like Growth Factor-1 ... Hormone (LH) Lyme Disease Tests Magnesium Maternal Serum Screening, ...

Using classical test theory, item response theory, and Rasch measurement theory to evaluate patient-reported outcome measures: a comparison of worked examples.

PubMed

Petrillo, Jennifer; Cano, Stefan J; McLeod, Lori D; Coon, Cheryl D

2015-01-01

To provide comparisons and a worked example of item- and scale-level evaluations based on three psychometric methods used in patient-reported outcome development-classical test theory (CTT), item response theory (IRT), and Rasch measurement theory (RMT)-in an analysis of the National Eye Institute Visual Functioning Questionnaire (VFQ-25). Baseline VFQ-25 data from 240 participants with diabetic macular edema from a randomized, double-masked, multicenter clinical trial were used to evaluate the VFQ at the total score level. CTT, RMT, and IRT evaluations were conducted, and results were assessed in a head-to-head comparison. Results were similar across the three methods, with IRT and RMT providing more detailed diagnostic information on how to improve the scale. CTT led to the identification of two problematic items that threaten the validity of the overall scale score, sets of redundant items, and skewed response categories. IRT and RMT additionally identified poor fit for one item, many locally dependent items, poor targeting, and disordering of over half the response categories. Selection of a psychometric approach depends on many factors. Researchers should justify their evaluation method and consider the intended audience. If the instrument is being developed for descriptive purposes and on a restricted budget, a cursory examination of the CTT-based psychometric properties may be all that is possible. In a high-stakes situation, such as the development of a patient-reported outcome instrument for consideration in pharmaceutical labeling, however, a thorough psychometric evaluation including IRT or RMT should be considered, with final item-level decisions made on the basis of both quantitative and qualitative results. Copyright © 2015. Published by Elsevier Inc.

Impact of IRT item misfit on score estimates and severity classifications: an examination of PROMIS depression and pain interference item banks.

PubMed

Zhao, Yue

2017-03-01

In patient-reported outcome research that utilizes item response theory (IRT), using statistical significance tests to detect misfit is usually the focus of IRT model-data fit evaluations. However, such evaluations rarely address the impact/consequence of using misfitting items on the intended clinical applications. This study was designed to evaluate the impact of IRT item misfit on score estimates and severity classifications and to demonstrate a recommended process of model-fit evaluation. Using secondary data sources collected from the Patient-Reported Outcome Measurement Information System (PROMIS) wave 1 testing phase, analyses were conducted based on PROMIS depression (28 items; 782 cases) and pain interference (41 items; 845 cases) item banks. The identification of misfitting items was assessed using Orlando and Thissen's summed-score item-fit statistics and graphical displays. The impact of misfit was evaluated according to the agreement of both IRT-derived T-scores and severity classifications between inclusion and exclusion of misfitting items. The examination of the presence and impact of misfit suggested that item misfit had a negligible impact on the T-score estimates and severity classifications with the general population sample in the PROMIS depression and pain interference item banks, implying that the impact of item misfit was insignificant. Findings support the T-score estimates in the two item banks as robust against item misfit at both the group and individual levels and add confidence to the use of T-scores for severity diagnosis in the studied sample. Recommendations on approaches for identifying item misfit (statistical significance) and assessing the misfit impact (practical significance) are given.

Icing Simulation Research Supporting the Ice-Accretion Testing of Large-Scale Swept-Wing Models

NASA Technical Reports Server (NTRS)

Yadlin, Yoram; Monnig, Jaime T.; Malone, Adam M.; Paul, Bernard P.

2018-01-01

The work summarized in this report is a continuation of NASA's Large-Scale, Swept-Wing Test Articles Fabrication; Research and Test Support for NASA IRT contract (NNC10BA05 -NNC14TA36T) performed by Boeing under the NASA Research and Technology for Aerospace Propulsion Systems (RTAPS) contract. In the study conducted under RTAPS, a series of icing tests in the Icing Research Tunnel (IRT) have been conducted to characterize ice formations on large-scale swept wings representative of modern commercial transport airplanes. The outcome of that campaign was a large database of ice-accretion geometries that can be used for subsequent aerodynamic evaluation in other experimental facilities and for validation of ice-accretion prediction codes.

Rheumatoid Factor

MedlinePlus

... Cancer Therapy Glucose Tests Gonorrhea Testing Gram Stain Growth Hormone Haptoglobin hCG Pregnancy hCG Tumor Marker HDL Cholesterol ... Immunoreactive Trypsinogen (IRT) Influenza Tests Insulin Insulin-like Growth Factor-1 ... Hormone (LH) Lyme Disease Tests Magnesium Maternal Serum Screening, ...

Assessing the equivalence of Web-based and paper-and-pencil questionnaires using differential item and test functioning (DIF and DTF) analysis: a case of the Four-Dimensional Symptom Questionnaire (4DSQ).

PubMed

Terluin, Berend; Brouwers, Evelien P M; Marchand, Miquelle A G; de Vet, Henrica C W

2018-05-01

Many paper-and-pencil (P&P) questionnaires have been migrated to electronic platforms. Differential item and test functioning (DIF and DTF) analysis constitutes a superior research design to assess measurement equivalence across modes of administration. The purpose of this study was to demonstrate an item response theory (IRT)-based DIF and DTF analysis to assess the measurement equivalence of a Web-based version and the original P&P format of the Four-Dimensional Symptom Questionnaire (4DSQ), measuring distress, depression, anxiety, and somatization. The P&P group (n = 2031) and the Web group (n = 958) consisted of primary care psychology clients. Unidimensionality and local independence of the 4DSQ scales were examined using IRT and Yen's Q3. Bifactor modeling was used to assess the scales' essential unidimensionality. Measurement equivalence was assessed using IRT-based DIF analysis using a 3-stage approach: linking on the latent mean and variance, selection of anchor items, and DIF testing using the Wald test. DTF was evaluated by comparing expected scale scores as a function of the latent trait. The 4DSQ scales proved to be essentially unidimensional in both modalities. Five items, belonging to the distress and somatization scales, displayed small amounts of DIF. DTF analysis revealed that the impact of DIF on the scale level was negligible. IRT-based DIF and DTF analysis is demonstrated as a way to assess the equivalence of Web-based and P&P questionnaire modalities. Data obtained with the Web-based 4DSQ are equivalent to data obtained with the P&P version.

Thermographic Sensing For On-Line Industrial Control

NASA Astrophysics Data System (ADS)

Holmsten, Dag

1986-10-01

It is today's emergence of thermoelectrically cooled, highly accurate infrared linescanners and imaging systems that has definitely made on-line Infraread Thermography (IRT) possible. Specifically designed for continuous use, these scanners are equipped with dedicated software capable of monitoring and controlling highly complex thermodynamic situations. This paper will outline some possible implications of using IRT on-line by describing some uses of this technology in the steel-making (hot rolling) and automotive industries (machine-vision). A warning is also expressed that IRT technology not originally designed for automated applications e.g. high resolution, imaging systems, should not be directly applied to an on-line measurement situation without having its measurement resolution, accuracy and especially its repeatability, reliably proven. Some suitable testing procedures are briefly outlined at the end of the paper.

Psychometric characteristics of daily diaries for the Patient-Reported Outcomes Measurement Information System (PROMIS®): a preliminary investigation.

PubMed

Schneider, Stefan; Choi, Seung W; Junghaenel, Doerte U; Schwartz, Joseph E; Stone, Arthur A

2013-09-01

The Patient-Reported Outcomes (PRO) Measurement Information System (PROMIS(®)) has developed assessment tools for numerous PROs, most using a 7-day recall format. We examined whether modifying the recall period for use in daily diary research would affect the psychometric characteristics of several PROMIS measures. Daily versions of short-forms for three PROMIS domains (pain interference, fatigue, depression) were administered to a general population sample (n = 100) for 28 days. Analyses used multilevel item response theory (IRT) models. We examined differential item functioning (DIF) across recall periods by comparing the IRT parameters from the daily data with the PROMIS 7-day recall IRT parameters. Additionally, we examined whether the IRT parameters for day-to-day within-person changes are invariant to those for between-person (cross-sectional) differences in PROs. Dimensionality analyses of the daily data suggested a single dimension for each PRO domain, consistent with PROMIS instruments. One-third of the daily items showed uniform DIF when compared with PROMIS 7-day recall, but the impact of DIF on the scale level was minor. IRT parameters for within-person changes differed from between-person parameters for 3 depression items, which were more sensitive for measuring change than between-person differences, but not for pain interference and fatigue items. Notably, mean scores from daily diaries were significantly lower than the PROMIS 7-day recall norms. The results provide initial evidence supporting the adaptation of PROMIS measures for daily diary research. However, scores from daily diaries cannot be directly interpreted on PROMIS norms established for 7-day recall.

Administrative Action to End Discrimination Based on Handicap: HEW's Section 504 Regulation.

ERIC Educational Resources Information Center

Engebretson, Mark F.

1979-01-01

Examines the drafting of regulations under Section 504 of the Rehabilitation Act of 1973, which prohibits discrimination against handicapped persons by recipients of federal funds. Available from Harvard Legislative Research Bureau, Langdell Hall, Harvard Law School, Cambridge, MA 02138; single copy $4.00. (Author/IRT)

Cognitive psychology meets psychometric theory: on the relation between process models for decision making and latent variable models for individual differences.

PubMed

van der Maas, Han L J; Molenaar, Dylan; Maris, Gunter; Kievit, Rogier A; Borsboom, Denny

2011-04-01

This article analyzes latent variable models from a cognitive psychology perspective. We start by discussing work by Tuerlinckx and De Boeck (2005), who proved that a diffusion model for 2-choice response processes entails a 2-parameter logistic item response theory (IRT) model for individual differences in the response data. Following this line of reasoning, we discuss the appropriateness of IRT for measuring abilities and bipolar traits, such as pro versus contra attitudes. Surprisingly, if a diffusion model underlies the response processes, IRT models are appropriate for bipolar traits but not for ability tests. A reconsideration of the concept of ability that is appropriate for such situations leads to a new item response model for accuracy and speed based on the idea that ability has a natural zero point. The model implies fundamentally new ways to think about guessing, response speed, and person fit in IRT. We discuss the relation between this model and existing models as well as implications for psychology and psychometrics. 2011 APA, all rights reserved

Robust Measurement via A Fused Latent and Graphical Item Response Theory Model.

PubMed

Chen, Yunxiao; Li, Xiaoou; Liu, Jingchen; Ying, Zhiliang

2018-03-12

Item response theory (IRT) plays an important role in psychological and educational measurement. Unlike the classical testing theory, IRT models aggregate the item level information, yielding more accurate measurements. Most IRT models assume local independence, an assumption not likely to be satisfied in practice, especially when the number of items is large. Results in the literature and simulation studies in this paper reveal that misspecifying the local independence assumption may result in inaccurate measurements and differential item functioning. To provide more robust measurements, we propose an integrated approach by adding a graphical component to a multidimensional IRT model that can offset the effect of unknown local dependence. The new model contains a confirmatory latent variable component, which measures the targeted latent traits, and a graphical component, which captures the local dependence. An efficient proximal algorithm is proposed for the parameter estimation and structure learning of the local dependence. This approach can substantially improve the measurement, given no prior information on the local dependence structure. The model can be applied to measure both a unidimensional latent trait and multidimensional latent traits.

What are the appropriate methods for analyzing patient-reported outcomes in randomized trials when data are missing?

PubMed

Hamel, J F; Sebille, V; Le Neel, T; Kubis, G; Boyer, F C; Hardouin, J B

2017-12-01

Subjective health measurements using Patient Reported Outcomes (PRO) are increasingly used in randomized trials, particularly for patient groups comparisons. Two main types of analytical strategies can be used for such data: Classical Test Theory (CTT) and Item Response Theory models (IRT). These two strategies display very similar characteristics when data are complete, but in the common case when data are missing, whether IRT or CTT would be the most appropriate remains unknown and was investigated using simulations. We simulated PRO data such as quality of life data. Missing responses to items were simulated as being completely random, depending on an observable covariate or on an unobserved latent trait. The considered CTT-based methods allowed comparing scores using complete-case analysis, personal mean imputations or multiple-imputations based on a two-way procedure. The IRT-based method was the Wald test on a Rasch model including a group covariate. The IRT-based method and the multiple-imputations-based method for CTT displayed the highest observed power and were the only unbiased method whatever the kind of missing data. Online software and Stata® modules compatibles with the innate mi impute suite are provided for performing such analyses. Traditional procedures (listwise deletion and personal mean imputations) should be avoided, due to inevitable problems of biases and lack of power.

PROC IRT: A SAS Procedure for Item Response Theory

PubMed Central

Matlock Cole, Ki; Paek, Insu

2017-01-01

This article reviews the procedure for item response theory (PROC IRT) procedure in SAS/STAT 14.1 to conduct item response theory (IRT) analyses of dichotomous and polytomous datasets that are unidimensional or multidimensional. The review provides an overview of available features, including models, estimation procedures, interfacing, input, and output files. A small-scale simulation study evaluates the IRT model parameter recovery of the PROC IRT procedure. The use of the IRT procedure in Statistical Analysis Software (SAS) may be useful for researchers who frequently utilize SAS for analyses, research, and teaching.

What to Expect If Your Legislature Orders Literacy Testing

ERIC Educational Resources Information Center

Van Til, William

1978-01-01

Based on the Florida experience, one should expect, among other things, new problems for minority students, lawsuits against the tests, calls for tests of teachers, and scapegoating and blaming. (Author/IRT)

An integrated study for mapping the moisture distribution in an ancient damaged wall painting.

PubMed

Capitani, Donatella; Proietti, Noemi; Gobbino, Marco; Soroldoni, Luigi; Casellato, Umberto; Valentini, Massimo; Rosina, Elisabetta

2009-12-01

An integrated study of microclimate monitoring, IR thermography (IRT), gravimetric tests and portable unilateral nuclear magnetic resonance (NMR) was applied in the framework of planning emergency intervention on a very deteriorated wall painting in San Rocco church, Cornaredo (Milan, Italy). The IRT investigation supported by gravimetric tests showed that the worst damage, due to water infiltration, was localized on the wall painting of the northern wall. Unilateral NMR, a new non-destructive technique which measures the hydrogen signal of the moisture and that was applied directly to the wall, allowed a detailed map of the distribution of the moisture in the plaster underlying the wall panting to be obtained. With a proper calibration of the integral of the recorded signal with suitable specimens, each area of the map corresponded to an accurate amount of moisture. IRT, gravimetric tests and unilateral NMR applied to investigate the northern wall painting showed the presence of two wet areas separated by a dry area. The moisture found in the lower area was ascribed to the occurrence of rising damp at the bottom of the wall due to the slope of the garden soil towards the northern exterior. The moisture found in the upper area was ascribed to condensation phenomena associated with the presence of a considerable amount of soluble, hygroscopic salts. In the framework of this integrated study, IRT investigation and gravimetric methods validated portable unilateral NMR as a new analytical tool for measuring in situ and without any sampling of the distribution and amount of moisture in wall paintings.

Measuring the ICF components of impairment, activity limitation and participation restriction: an item analysis using classical test theory and item response theory

PubMed Central

Pollard, Beth; Dixon, Diane; Dieppe, Paul; Johnston, Marie

2009-01-01

Background The International Classification of Functioning, Disability and Health (ICF) proposes three main health outcomes, Impairment (I), Activity Limitation (A) and Participation Restriction (P), but good measures of these constructs are needed The aim of this study was to use both Classical Test Theory (CTT) and Item Response Theory (IRT) methods to carry out an item analysis to improve measurement of these three components in patients having joint replacement surgery mainly for osteoarthritis (OA). Methods A geographical cohort of patients about to undergo lower limb joint replacement was invited to participate. Five hundred and twenty four patients completed ICF items that had been previously identified as measuring only a single ICF construct in patients with osteoarthritis. There were 13 I, 26 A and 20 P items. The SF-36 was used to explore the construct validity of the resultant I, A and P measures. The CTT and IRT analyses were run separately to identify items for inclusion or exclusion in the measurement of each construct. The results from both analyses were compared and contrasted. Results Overall, the item analysis resulted in the removal of 4 I items, 9 A items and 11 P items. CTT and IRT identified the same 14 items for removal, with CTT additionally excluding 3 items, and IRT a further 7 items. In a preliminary exploration of reliability and validity, the new measures appeared acceptable. Conclusion New measures were developed that reflect the ICF components of Impairment, Activity Limitation and Participation Restriction for patients with advanced arthritis. The resulting Aberdeen IAP measures (Ab-IAP) comprising I (Ab-I, 9 items), A (Ab-A, 17 items), and P (Ab-P, 9 items) met the criteria of conventional psychometric (CTT) analyses and the additional criteria (information and discrimination) of IRT. The use of both methods was more informative than the use of only one of these methods. Thus combining CTT and IRT appears to be a valuable tool in the development of measures. PMID:19422677

Procedures to develop a computerized adaptive test to assess patient-reported physical functioning.

PubMed

McCabe, Erin; Gross, Douglas P; Bulut, Okan

2018-06-07

The purpose of this paper is to demonstrate the procedures to develop and implement a computerized adaptive patient-reported outcome (PRO) measure using secondary analysis of a dataset and items from fixed-format legacy measures. We conducted secondary analysis of a dataset of responses from 1429 persons with work-related lower extremity impairment. We calibrated three measures of physical functioning on the same metric, based on item response theory (IRT). We evaluated efficiency and measurement precision of various computerized adaptive test (CAT) designs using computer simulations. IRT and confirmatory factor analyses support combining the items from the three scales for a CAT item bank of 31 items. The item parameters for IRT were calculated using the generalized partial credit model. CAT simulations show that reducing the test length from the full 31 items to a maximum test length of 8 items, or 20 items is possible without a significant loss of information (95, 99% correlation with legacy measure scores). We demonstrated feasibility and efficiency of using CAT for PRO measurement of physical functioning. The procedures we outlined are straightforward, and can be applied to other PRO measures. Additionally, we have included all the information necessary to implement the CAT of physical functioning in the electronic supplementary material of this paper.

Response pattern of depressive symptoms among college students: What lies behind items of the Beck Depression Inventory-II?

PubMed

de Sá Junior, Antonio Reis; de Andrade, Arthur Guerra; Andrade, Laura Helena; Gorenstein, Clarice; Wang, Yuan-Pang

2018-07-01

This study examines the response pattern of depressive symptoms in a nationwide student sample, through item analyses of a rating scale by both classical test theory (CTT) and item response theory (IRT). The 21-item Beck Depression Inventory-II (BDI-II) was administered to 12,711 college students. First, the psychometric properties of the scale were described. Thereafter, the endorsement probability of depressive symptom in each scale item was analyzed through CTT and IRT. Graphical plots depicted the endorsement probability of scale items and intensity of depression. Three items of different difficulty level were compared through CTT and IRT approach. Four in five students reported the presence of depressive symptoms. The BDI-II items presented good reliability and were distributed along the symptomatic continuum of depression. Similarly, in both CTT and IRT approaches, the item 'changes in sleep' was easily endorsed, 'loss of interest' moderately and 'suicidal thoughts' hardly. Graphical representation of BDI-II of both methods showed much equivalence in terms of item discrimination and item difficulty. The item characteristic curve of the IRT method provided informative evaluation of item performance. The inventory was applied only in college students. Depressive symptoms were frequent psychopathological manifestations among college students. The performance of the BDI-II items indicated convergent results from both methods of analysis. While the CTT was easy to understand and to apply, the IRT was more complex to understand and to implement. Comprehensive assessment of the functioning of each BDI-II item might be helpful in efficient detection of depressive conditions in college students. Copyright © 2018 Elsevier B.V. All rights reserved.

Screening for cystic fibrosis in New York State: considerations for algorithm improvements.

PubMed

Kay, Denise M; Maloney, Breanne; Hamel, Rhonda; Pearce, Melissa; DeMartino, Lenore; McMahon, Rebecca; McGrath, Emily; Krein, Lea; Vogel, Beth; Saavedra-Matiz, Carlos A; Caggana, Michele; Tavakoli, Norma P

2016-02-01

Newborn screening for cystic fibrosis (CF), a chronic progressive disease affecting mucus viscosity, has been beneficial in both improving life expectancy and the quality of life for individuals with CF. In New York State from 2007 to 2012 screening for CF involved measuring immunoreactive trypsinogen (IRT) levels in dried blood spots from newborns using the IMMUCHEM(™) Blood Spot Trypsin-MW ELISA kit. Any specimen in the top 5% IRT level underwent DNA analysis using the InPlex(®) CF Molecular Test. Of the 1.48 million newborns screened during the 6-year time period, 7631 babies were referred for follow-up. CF was confirmed in 251 cases, and 94 cases were diagnosed with CF transmembrane conductance regulated-related metabolic syndrome or possible CF. Nine reports of false negatives were made to the program. Variation in daily average IRT was observed depending on the season (4-6 ng/ml) and kit lot (<3 ng/ml), supporting the use of a floating cutoff. The screening method had a sensitivity of 96.5%, specificity of 99.6%, positive predictive value of 4.5%, and negative predictive value of 99.5%. Considerations for CF screening algorithms should include IRT variations resulting from age at specimen collection, sex, race/ethnicity, season, and manufacturer kit lots. Measuring IRT level in dried blood spots is the first-tier screen for CF. Current algorithms for CF screening lead to substantial false-positive referral rates. IRT values were affected by age of infant when specimen is collected, race/ethnicity and sex of infant, and changes in seasons and manufacturer kit lots The prevalence of CF in NYS is 1 in 4200 with the highest prevalence in White infants (1 in 2600) and the lowest in Black infants (1 in 15,400).

The Supreme Court Holds That Section 504 Does Not Require Affirmative Action.

ERIC Educational Resources Information Center

Flygare, Thomas J.

1979-01-01

In deciding that a person with a serious hearing handicap could be denied entry into a nursing program, the Supreme Court held that Section 504 of the Rehabilitation Act of 1973 does not require affirmative action but imposes the lesser obligation that institutions avoid discrimination against handicapped persons. (Author/IRT)

Evaluation properties of the French version of the OUT-PATSAT35 satisfaction with care questionnaire according to classical and item response theory analyses.

PubMed

Panouillères, M; Anota, A; Nguyen, T V; Brédart, A; Bosset, J F; Monnier, A; Mercier, M; Hardouin, J B

2014-09-01

The present study investigates the properties of the French version of the OUT-PATSAT35 questionnaire, which evaluates the outpatients' satisfaction with care in oncology using classical analysis (CTT) and item response theory (IRT). This cross-sectional multicenter study includes 692 patients who completed the questionnaire at the end of their ambulatory treatment. CTT analyses tested the main psychometric properties (convergent and divergent validity, and internal consistency). IRT analyses were conducted separately for each OUT-PATSAT35 domain (the doctors, the nurses or the radiation therapists and the services/organization) by models from the Rasch family. We examined the fit of the data to the model expectations and tested whether the model assumptions of unidimensionality, monotonicity and local independence were respected. A total of 605 (87.4%) respondents were analyzed with a mean age of 64 years (range 29-88). Internal consistency for all scales separately and for the three main domains was good (Cronbach's α 0.74-0.98). IRT analyses were performed with the partial credit model. No disordered thresholds of polytomous items were found. Each domain showed high reliability but fitted poorly to the Rasch models. Three items in particular, the item about "promptness" in the doctors' domain and the items about "accessibility" and "environment" in the services/organization domain, presented the highest default of fit. A correct fit of the Rasch model can be obtained by dropping these items. Most of the local dependence concerned items about "information provided" in each domain. A major deviation of unidimensionality was found in the nurses' domain. CTT showed good psychometric properties of the OUT-PATSAT35. However, the Rasch analysis revealed some misfitting and redundant items. Taking the above problems into consideration, it could be interesting to refine the questionnaire in a future study.

Clinical Application Of Advanced Infrared Thermography (IRT) In Locomotor Diseases

NASA Astrophysics Data System (ADS)

Engel, Joachim-Michael

1983-11-01

Locomotor diseases is a wide range of about 450 different illnesses with all different pathologies, clinical and prognostic features and response to treatment. No single method will be able to cover the whole spectrum of local and systemic signs and symptoms. Nevertheless there is a need for objective measurements at the site of disease: clinical examination is often enough depending from subjective estimations and personal experiance of the clinician. Laboratory tests only show the systemic effect of the disease, like inflammation. X-rays are restricted to the detection of structural changes appearing late during the pathological process, even when using different techniques. Here IRT offers several advantages to the clinician as well as to the patient. As a non invasive method it monitors the course of disease at the anatomic site of pathology. Quantitative figures calculated from the thermogram,either taken at steady-state or during dynamic tests, are essential for differential diagnosis and follow-up. Advanced IRT camera systems fulfill all requirements set up for medical thermography recently by the National Bureau of Standards. Although, the user should check his system daily with regard to precision of absolute temperature measurements. Standardisation of recording technique is essential as well,to get reliable results. Ambient conditions must be adapted to the locomotor disease pathology under study. Advanced IRT systems , e.g. ZEISS-IKOTHERM, together with image processing capability and special software, e.g. THERMOTOM package, are valuable tools to the rheumatologist for diagnosing and monitoring locomotor diseases.

Small helium-cooled infrared telescope experiment for Spacelab-2 (IRT)

NASA Technical Reports Server (NTRS)

Fazio, Giovanni G.

1990-01-01

The Infrared Telescope (IRT) experiment, flown on Spacelab-2, was used to make infrared measurements between 2 and 120 microns. The objectives were multidisciplinary in nature with astrophysical goals of mapping the diffuse cosmic emission and extended infrared sources and technical goals of measuring the induced Shuttle environment, studying properties of superfluid helium in space, and testing various infrared telescope system designs. Astrophysically, new data were obtained on the structure of the Galaxy at near-infrared wavelengths. A summary of the large scale diffuse near-infrared observations of the Galaxy by the IRT is presented, as well as a summary of the preliminary results obtained from this data on the structure of the galactic disk and bulge. The importance of combining CO and near-infrared maps of similar resolution to determine a 3-D model of galactic extinction is demonstrated. The IRT data are used, in conjunction with a proposed galactic model, to make preliminary measurements of the global scale parameters of the Galaxy. During the mission substantial amounts of data were obtained concerning the induced Shuttle environment. An experiment was also performed to measure spacecraft glow in the IR.

Mixture Rasch model for guessing group identification

NASA Astrophysics Data System (ADS)

Siow, Hoo Leong; Mahdi, Rasidah; Siew, Eng Ling

2013-04-01

Several alternative dichotomous Item Response Theory (IRT) models have been introduced to account for guessing effect in multiple-choice assessment. The guessing effect in these models has been considered to be itemrelated. In the most classic case, pseudo-guessing in the three-parameter logistic IRT model is modeled to be the same for all the subjects but may vary across items. This is not realistic because subjects can guess worse or better than the pseudo-guessing. Derivation from the three-parameter logistic IRT model improves the situation by incorporating ability in guessing. However, it does not model non-monotone function. This paper proposes to study guessing from a subject-related aspect which is guessing test-taking behavior. Mixture Rasch model is employed to detect latent groups. A hybrid of mixture Rasch and 3-parameter logistic IRT model is proposed to model the behavior based guessing from the subjects' ways of responding the items. The subjects are assumed to simply choose a response at random. An information criterion is proposed to identify the behavior based guessing group. Results show that the proposed model selection criterion provides a promising method to identify the guessing group modeled by the hybrid model.

Method variation in the impact of missing data on response shift detection.

PubMed

Schwartz, Carolyn E; Sajobi, Tolulope T; Verdam, Mathilde G E; Sebille, Veronique; Lix, Lisa M; Guilleux, Alice; Sprangers, Mirjam A G

2015-03-01

Missing data due to attrition or item non-response can result in biased estimates and loss of power in longitudinal quality-of-life (QOL) research. The impact of missing data on response shift (RS) detection is relatively unknown. This overview article synthesizes the findings of three methods tested in this special section regarding the impact of missing data patterns on RS detection in incomplete longitudinal data. The RS detection methods investigated include: (1) Relative importance analysis to detect reprioritization RS in stroke caregivers; (2) Oort's structural equation modeling (SEM) to detect recalibration, reprioritization, and reconceptualization RS in cancer patients; and (3) Rasch-based item-response theory-based (IRT) models as compared to SEM models to detect recalibration and reprioritization RS in hospitalized chronic disease patients. Each method dealt with missing data differently, either with imputation (1), attrition-based multi-group analysis (2), or probabilistic analysis that is robust to missingness due to the specific objectivity property (3). Relative importance analyses were sensitive to the type and amount of missing data and imputation method, with multiple imputation showing the largest RS effects. The attrition-based multi-group SEM revealed differential effects of both the changes in health-related QOL and the occurrence of response shift by attrition stratum, and enabled a more complete interpretation of findings. The IRT RS algorithm found evidence of small recalibration and reprioritization effects in General Health, whereas SEM mostly evidenced small recalibration effects. These differences may be due to differences between the two methods in handling of missing data. Missing data imputation techniques result in different conclusions about the presence of reprioritization RS using the relative importance method, while the attrition-based SEM approach highlighted different recalibration and reprioritization RS effects by attrition group. The IRT analyses detected more recalibration and reprioritization RS effects than SEM, presumably due to IRT's robustness to missing data. Future research should apply simulation techniques in order to make conclusive statements about the impacts of missing data according to the type and amount of RS.

Overview of the Icing and Flow Quality Improvements Program for the NASA Glenn Icing Research Tunnel

NASA Technical Reports Server (NTRS)

Irvine, Thomas B.; Kevdzija, Susan L.; Sheldon, David W.; Spera, David A.

2001-01-01

Major upgrades were made in 1999 to the 6- by 9-Foot (1.8- by 2.7-m) Icing Research Tunnel (IRT) at the NASA Glenn Research Center. These included replacement of the electronic controls for the variable-speed drive motor, replacement of the heat exchanger, complete replacement and enlargement of the leg of the tunnel containing the new heat-exchanger, the addition of flow-expanding and flow-contracting turning vanes upstream and downstream of the heat exchanger, respectively, and the addition of fan outlet guide vanes (OGV's). This paper describes the rationale behind this latest program of IRT upgrades and the program's requirements and goals. An overview is given of the scope of work undertaken by the design and construction contractors, the scale-model IRT (SMIRT) design verification program, the comprehensive reactivation test program initiated upon completion of construction, and the overall management approach followed.

A quantitative comparison of noise reduction across five commercial (hybrid and model-based) iterative reconstruction techniques: an anthropomorphic phantom study.

PubMed

Patino, Manuel; Fuentes, Jorge M; Hayano, Koichi; Kambadakone, Avinash R; Uyeda, Jennifer W; Sahani, Dushyant V

2015-02-01

OBJECTIVE. The objective of our study was to compare the performance of three hybrid iterative reconstruction techniques (IRTs) (ASiR, iDose4, SAFIRE) and their respective strengths for image noise reduction on low-dose CT examinations using filtered back projection (FBP) as the standard reference. Also, we compared the performance of these three hybrid IRTs with two model-based IRTs (Veo and IMR) for image noise reduction on low-dose examinations. MATERIALS AND METHODS. An anthropomorphic abdomen phantom was scanned at 100 and 120 kVp and different tube current-exposure time products (25-100 mAs) on three CT systems (for ASiR and Veo, Discovery CT750 HD; for iDose4 and IMR, Brilliance iCT; and for SAFIRE, Somatom Definition Flash). Images were reconstructed using FBP and using IRTs at various strengths. Nine noise measurements (mean ROI size, 423 mm(2)) on extracolonic fat for the different strengths of IRTs were recorded and compared with FBP using ANOVA. Radiation dose, which was measured as the volume CT dose index and dose-length product, was also compared. RESULTS. There were no significant differences in radiation dose and image noise among the scanners when FBP was used (p > 0.05). Gradual image noise reduction was observed with each increasing increment of hybrid IRT strength, with a maximum noise suppression of approximately 50% (48.2-53.9%). Similar noise reduction was achieved on the scanners by applying specific hybrid IRT strengths. Maximum noise reduction was higher on model-based IRTs (68.3-81.1%) than hybrid IRTs (48.2-53.9%) (p < 0.05). CONCLUSION. When constant scanning parameters are used, radiation dose and image noise on FBP are similar for CT scanners made by different manufacturers. Significant image noise reduction is achieved on low-dose CT examinations rendered with IRTs. The image noise on various scanners can be matched by applying specific hybrid IRT strengths. Model-based IRTs attain substantially higher noise reduction than hybrid IRTs irrespective of the radiation dose.

Expression of Malus xiaojinensis IRT1 (MxIRT1) protein in transgenic yeast cells leads to degradation through autophagy in the presence of excessive iron.

PubMed

Li, Shuang; Zhang, Xi; Zhang, Xiu-Yue; Xiao, Wei; Berry, James O; Li, Peng; Jin, Si; Tan, Song; Zhang, Peng; Zhao, Wei-Zhong; Yin, Li-Ping

2015-07-01

Iron is essential for plants, but highly toxic when present in excess. Consequently, iron uptake by root transporters must be finely tuned to avoid excess uptake from soil under iron excess. The iron-regulated transporter of Malus xiaojinensis (MxIRT1), induced in roots under iron deficiency, is a highly effective iron(II) transporter. Here, we investigated how the presence of excessive iron leads to MxIRT1 degradation in yeast expressing this plant iron transporter protein. To determine the relationship between iron abundance and MxIRT1 degradation, relative levels of autophagy-related gene-8 (ATG8) mRNA and the active ATG8-phosphatidylethanolamine-conjugated (PE) protein were measured in wild-type yeast and the autophagic mutant strains atg1∆, atg5∆, atg7∆, ypt7∆ and tor1∆ under normal and excessive iron conditions. The data showed that the exposure of MxIRT1-eGFP-transformed wild-type and tor1∆ strains to excessive iron led to significantly increased levels of ATG8 transcript and ATG8-PE protein, which resulted in enhanced MxIRT1 degradation. Co-localization of mCherry-ATG8 and MxIRT1-eGFP provided evidence that these proteins interact during autophagy in yeast. While inhibition of autophagic initiation, autophagosome formation and vacuole fusion all decreased MxIRT1 degradation. PMSF inhibition of autophagy prevented degradation, leading to the accumulation of MxIRT1-containing vesicles in the vacuoles. MxIRT1-vesicles were sorted into autophagosomes for iron-induced degradation in yeast, whereas the endogenous iron(II) transporter Fet4 was degraded in an autophagy-independent manner. Moreover, immunoprecipitation showed that multimono-ubiquitins provided MxIRT1 with the ubiquitination signal. Together, three factors, iron excess, autophagy and mono-ubiquitination, affect the functional activity and stability of exogenous MxIRT1 in yeast, thereby preventing iron uptake via this root transporter. Copyright © 2015 John Wiley & Sons, Ltd.

An uncleaved signal peptide directs the Malus xiaojinensis iron transporter protein Mx IRT1 into the ER for the PM secretory pathway.

PubMed

Zhang, Peng; Tan, Song; Berry, James O; Li, Peng; Ren, Na; Li, Shuang; Yang, Guang; Wang, Wei-Bing; Qi, Xiao-Ting; Yin, Li-Ping

2014-11-07

Malus xiaojinensis iron-regulated transporter 1 (Mx IRT1) is a highly effective inducible iron transporter in the iron efficient plant Malus xiaojinensis. As a multi-pass integral plasma membrane (PM) protein, Mx IRT1 is predicted to consist of eight transmembrane domains, with a putative N-terminal signal peptide (SP) of 1-29 amino acids. To explore the role of the putative SP, constructs expressing Mx IRT1 (with an intact SP) and Mx DsIRT1 (with a deleted SP) were prepared for expression in Arabidopsis and in yeast. Mx IRT1 could rescue the iron-deficiency phenotype of an Arabidopsis irt1 mutant, and complement the iron-limited growth defect of the yeast mutant DEY 1453 (fet3fet4). Furthermore, fluorescence analysis indicated that a chimeric Mx IRT1-eGFP (enhanced Green Fluorescent Protein) construct was translocated into the ER (Endoplasmic reticulum) for the PM sorting pathway. In contrast, the SP-deleted Mx DsIRT1 could not rescue either of the mutant phenotypes, nor direct transport of the GFP signal into the ER. Interestingly, immunoblot analysis indicated that the SP was not cleaved from the mature protein following transport into the ER. Taken together, data presented here provides strong evidence that an uncleaved SP determines ER-targeting of Mx IRT1 during the initial sorting stage, thereby enabling the subsequent transport and integration of this protein into the PM for its crucial role in iron uptake.

Implementation of an Improved Adaptive Testing Theory

ERIC Educational Resources Information Center

Al-A'ali, Mansoor

2007-01-01

Computer adaptive testing is the study of scoring tests and questions based on assumptions concerning the mathematical relationship between examinees' ability and the examinees' responses. Adaptive student tests, which are based on item response theory (IRT), have many advantages over conventional tests. We use the least square method, a…

The Exploration of the Relationship between Guessing and Latent Ability in IRT Models

ERIC Educational Resources Information Center

Gao, Song

2011-01-01

This study explored the relationship between successful guessing and latent ability in IRT models. A new IRT model was developed with a guessing function integrating probability of guessing an item correctly with the examinee's ability and the item parameters. The conventional 3PL IRT model was compared with the new 2PL-Guessing model on…

Results of a low power ice protection system test and a new method of imaging data analysis

NASA Technical Reports Server (NTRS)

Shin, Jaiwon; Bond, Thomas H.; Mesander, Geert A.

1992-01-01

Tests were conducted on a BF Goodrich De-Icing System's Pneumatic Impulse Ice Protection (PIIP) system in the NASA Lewis Icing Research Tunnel (IRT). Characterization studies were done on shed ice particle size by changing the input pressure and cycling time of the PIIP de-icer. The shed ice particle size was quantified using a newly developed image software package. The tests were conducted on a 1.83 m (6 ft) span, 0.53 m (221 in) chord NACA 0012 airfoil operated at a 4 degree angle of attack. The IRT test conditions were a -6.7 C (20 F) glaze ice, and a -20 C (-4 F) rime ice. The ice shedding events were recorded with a high speed video system. A detailed description of the image processing package and the results generated from this analytical tool are presented.

Validation of the Ten-Item Internet Gaming Disorder Test (IGDT-10) and evaluation of the nine DSM-5 Internet Gaming Disorder criteria.

PubMed

Király, Orsolya; Sleczka, Pawel; Pontes, Halley M; Urbán, Róbert; Griffiths, Mark D; Demetrovics, Zsolt

2017-01-01

The inclusion of Internet Gaming Disorder (IGD) in the DSM-5 (Section 3) has given rise to much scholarly debate regarding the proposed criteria and their operationalization. The present study's aim was threefold: to (i) develop and validate a brief psychometric instrument (Ten-Item Internet Gaming Disorder Test; IGDT-10) to assess IGD using definitions suggested in DSM-5, (ii) contribute to ongoing debate regards the usefulness and validity of each of the nine IGD criteria (using Item Response Theory [IRT]), and (iii) investigate the cut-off threshold suggested in the DSM-5. An online gamer sample of 4887 gamers (age range 14-64years, mean age 22.2years [SD=6.4], 92.5% male) was collected through Facebook and a gaming-related website with the cooperation of a popular Hungarian gaming magazine. A shopping voucher of approx. 300 Euros was drawn between participants to boost participation (i.e., lottery incentive). Confirmatory factor analysis and a structural regression model were used to test the psychometric properties of the IGDT-10 and IRT analysis was conducted to test the measurement performance of the nine IGD criteria. Finally, Latent Class Analysis along with sensitivity and specificity analysis were used to investigate the cut-off threshold proposed in the DSM-5. Analysis supported IGDT-10's validity, reliability, and suitability to be used in future research. Findings of the IRT analysis suggest IGD is manifested through a different set of symptoms depending on the level of severity of the disorder. More specifically, "continuation", "preoccupation", "negative consequences" and "escape" were associated with lower severity of IGD, while "tolerance", "loss of control", "giving up other activities" and "deception" criteria were associated with more severe levels. "Preoccupation" and "escape" provided very little information to the estimation IGD severity. Finally, the DSM-5 suggested threshold appeared to be supported by our statistical analyses. IGDT-10 is a valid and reliable instrument to assess IGD as proposed in the DSM-5. Apparently the nine criteria do not explain IGD in the same way, suggesting that additional studies are needed to assess the characteristics and intricacies of each criterion and how they account to explain IGD. Copyright © 2015 Elsevier Ltd. All rights reserved.

An Assessment of the Icing Blade and the SEA Multi-Element Sensor for Liquid Water Content Calibration of the NASA GRC Icing Research Tunnel

NASA Technical Reports Server (NTRS)

Steen, Laura E.; Ide, Robert F.; Van Zante, Judith F.

2016-01-01

The Icing Research Tunnel at NASA Glenn has recently switched from using the Icing Blade to using the SEA Multi-Element Sensor (also known as the multi-wire) for its calibration of cloud liquid water content. In order to peform this transition, tests were completed to compare the Multi-Element Sensor to the Icing Blade, particularly with respect to liquid water content, airspeed, and drop size. The two instruments were found to compare well for the majority of Appendix C conditions. However, it was discovered that the Icing Blade under-measures when the conditions approach the Ludlam Limit. This paper also describes data processing procedures for the Multi-Element Sensor in the IRT, including collision efficiency corrections, mounting underneath a splitter plate, and correcting for a jump in the compensation wire power. Further data is presented to describe the repeatability of the IRT with the Multi-Element Sensor, health-monitoring checks for the instrument, and a sensing-element configuration comparison. Ultimately these tests showed that in the IRT, the multi-wire is a better instrument for measuring cloud liquid water content than the blade.

Human instrumental performance in ratio and interval contingencies: A challenge for associative theory.

PubMed

Pérez, Omar D; Aitken, Michael R F; Zhukovsky, Peter; Soto, Fabián A; Urcelay, Gonzalo P; Dickinson, Anthony

2016-12-15

Associative learning theories regard the probability of reinforcement as the critical factor determining responding. However, the role of this factor in instrumental conditioning is not completely clear. In fact, free-operant experiments show that participants respond at a higher rate on variable ratio than on variable interval schedules even though the reinforcement probability is matched between the schedules. This difference has been attributed to the differential reinforcement of long inter-response times (IRTs) by interval schedules, which acts to slow responding. In the present study, we used a novel experimental design to investigate human responding under random ratio (RR) and regulated probability interval (RPI) schedules, a type of interval schedule that sets a reinforcement probability independently of the IRT duration. Participants responded on each type of schedule before a final choice test in which they distributed responding between two schedules similar to those experienced during training. Although response rates did not differ during training, the participants responded at a lower rate on the RPI schedule than on the matched RR schedule during the choice test. This preference cannot be attributed to a higher probability of reinforcement for long IRTs and questions the idea that similar associative processes underlie classical and instrumental conditioning.

A Study of Large Droplet Ice Accretions in the NASA-Lewis IRT at Near-Freezing Conditions

NASA Technical Reports Server (NTRS)

Miller, Dean R.; Addy, Harold E. , Jr.; Ide, Robert F.

1996-01-01

This report documents the results of an experimental study on large droplet ice accretions which was conducted in the NASA-Lewis Icing Research Tunnel (IRT) with a full-scale 77.25 inch chord Twin-Otter wing section. This study was intended to: (1) document the existing capability of the IRT to produce a large droplet icing cloud, and (2) study the effect of various parameters on large droplet ice accretions. Results are presented from a study of the IRT's capability to produce large droplets with MVD of 99 and 160 microns. The effect of the initial water droplet temperature on the resultant ice accretion was studied for different initial spray bar air and water temperatures. The initial spray bar water temperature was found to have no discernible effect upon the large droplet ice accretions. Also, analytical and experimental results suggest that the water droplet temperature is very nearly the same as the tunnel ambient temperature, thus providing a realistic simulation of the large droplet natural icing condition. The effect of temperature, droplet size, airspeed, angle-of attack, flap setting and de-icer boot cycling time on ice accretion was studied, and will be discussed in this report. It was found that, in almost all of the cases studied, an ice ridge formed immediately aft of the active portion of the de-icer boot. This ridge was irregular in shape, varied in location, and was in some cases discontinuous due to aerodynamic shedding.

Spectral Analysis and Experimental Modeling of Ice Accretion Roughness

NASA Technical Reports Server (NTRS)

Orr, D. J.; Breuer, K. S.; Torres, B. E.; Hansman, R. J., Jr.

1996-01-01

A self-consistent scheme for relating wind tunnel ice accretion roughness to the resulting enhancement of heat transfer is described. First, a spectral technique of quantitative analysis of early ice roughness images is reviewed. The image processing scheme uses a spectral estimation technique (SET) which extracts physically descriptive parameters by comparing scan lines from the experimentally-obtained accretion images to a prescribed test function. Analysis using this technique for both streamwise and spanwise directions of data from the NASA Lewis Icing Research Tunnel (IRT) are presented. An experimental technique is then presented for constructing physical roughness models suitable for wind tunnel testing that match the SET parameters extracted from the IRT images. The icing castings and modeled roughness are tested for enhancement of boundary layer heat transfer using infrared techniques in a "dry" wind tunnel.

Item response theory scoring and the detection of curvilinear relationships.

PubMed

Carter, Nathan T; Dalal, Dev K; Guan, Li; LoPilato, Alexander C; Withrow, Scott A

2017-03-01

Psychologists are increasingly positing theories of behavior that suggest psychological constructs are curvilinearly related to outcomes. However, results from empirical tests for such curvilinear relations have been mixed. We propose that correctly identifying the response process underlying responses to measures is important for the accuracy of these tests. Indeed, past research has indicated that item responses to many self-report measures follow an ideal point response process-wherein respondents agree only to items that reflect their own standing on the measured variable-as opposed to a dominance process, wherein stronger agreement, regardless of item content, is always indicative of higher standing on the construct. We test whether item response theory (IRT) scoring appropriate for the underlying response process to self-report measures results in more accurate tests for curvilinearity. In 2 simulation studies, we show that, regardless of the underlying response process used to generate the data, using the traditional sum-score generally results in high Type 1 error rates or low power for detecting curvilinearity, depending on the distribution of item locations. With few exceptions, appropriate power and Type 1 error rates are achieved when dominance-based and ideal point-based IRT scoring are correctly used to score dominance and ideal point response data, respectively. We conclude that (a) researchers should be theory-guided when hypothesizing and testing for curvilinear relations; (b) correctly identifying whether responses follow an ideal point versus dominance process, particularly when items are not extreme is critical; and (c) IRT model-based scoring is crucial for accurate tests of curvilinearity. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Creating IRT-Based Parallel Test Forms Using the Genetic Algorithm Method

ERIC Educational Resources Information Center

Sun, Koun-Tem; Chen, Yu-Jen; Tsai, Shu-Yen; Cheng, Chien-Fen

2008-01-01

In educational measurement, the construction of parallel test forms is often a combinatorial optimization problem that involves the time-consuming selection of items to construct tests having approximately the same test information functions (TIFs) and constraints. This article proposes a novel method, genetic algorithm (GA), to construct parallel…

A Comparison of Three Test Formats to Assess Word Difficulty

ERIC Educational Resources Information Center

Culligan, Brent

2015-01-01

This study compared three common vocabulary test formats, the Yes/No test, the Vocabulary Knowledge Scale (VKS), and the Vocabulary Levels Test (VLT), as measures of vocabulary difficulty. Vocabulary difficulty was defined as the item difficulty estimated through Item Response Theory (IRT) analysis. Three tests were given to 165 Japanese students,…

New Damage Remedies for Violations of Constitutional Rights.

ERIC Educational Resources Information Center

Russell, Billy W.

1979-01-01

Examines the concept of sovereign (governmental) immunity from prosecution for violating citizens' civil liberties. Attention is given to immunity under 42 U.S.C.A. Section 1983 and under the Constitution. Available from Baylor University Law School, Waco, Texas 76703; sc $4.00. (IRT)

Experimental comparison of icing cloud instruments

NASA Technical Reports Server (NTRS)

Olsen, W.; Takeuchi, D. M.; Adams, K.

1983-01-01

Icing cloud instruments were tested in the spray cloud Icing Research Tunnel (IRT) in order to determine their relative accuracy and their limitations over a broad range of conditions. It was found that the average of the readings from each of the liquid water content (LWC) instruments tested agreed closely with each other and with the IRT calibration; but all have a data scatter (+ or - one standard deviation) of about + or - 20 percent. The effect of this + or - 20 percent uncertainty is probably acceptable in aero-penalty and deicer experiments. Existing laser spectrometers proved to be too inaccurate for LWC measurements. The error due to water runoff was the same for all ice accretion LWC instruments. Any given laser spectrometer proved to be highly repeatable in its indications of volume median drop size (DVM), LWC and drop size distribution. However, there was a significant disagreement between different spectrometers of the same model, even after careful standard calibration and data analysis. The scatter about the mean of the DVM data from five Axial Scattering Spectrometer Probes was + or - 20 percent (+ or - one standard deviation) and the average was 20 percent higher than the old IRT calibration. The + or - 20 percent uncertainty in DVM can cause an unacceptable variation in the drag coefficient of an airfoil with ice; however, the variation in a deicer performance test may be acceptable.

Development of 3-D Ice Accretion Measurement Method

NASA Technical Reports Server (NTRS)

Lee, Sam; Broeren, Andy P.; Addy, Harold E., Jr.; Sills, Robert; Pifer, Ellen M.

2012-01-01

A research plan is currently being implemented by NASA to develop and validate the use of a commercial laser scanner to record and archive fully three-dimensional (3-D) ice shapes from an icing wind tunnel. The plan focused specifically upon measuring ice accreted in the NASA Icing Research Tunnel (IRT). The plan was divided into two phases. The first phase was the identification and selection of the laser scanning system and the post-processing software to purchase and develop further. The second phase was the implementation and validation of the selected system through a series of icing and aerodynamic tests. Phase I of the research plan has been completed. It consisted of evaluating several scanning hardware and software systems against an established selection criteria through demonstrations in the IRT. The results of Phase I showed that all of the scanning systems that were evaluated were equally capable of scanning ice shapes. The factors that differentiated the scanners were ease of use and the ability to operate in a wide range of IRT environmental conditions.

Imagery rehearsal therapy in addition to treatment as usual for patients with diverse psychiatric diagnoses suffering from nightmares: a randomized controlled trial.

PubMed

van Schagen, Annette M; Lancee, Jaap; de Groot, Izaäk W; Spoormaker, Victor I; van den Bout, Jan

2015-09-01

Nightmares are associated with psychopathology and daily distress. They are highly prevalent in a psychiatric population (30%). Currently, imagery rehearsal therapy (IRT) is the treatment of choice for nightmares. With IRT, the script of the nightmare is changed into a new dream, which is imagined during the day. However, the effects of IRT in a psychiatric population remain unknown. The aim of this study was to determine the effectiveness of IRT in a heterogeneous psychiatric population. Between January 2006 and July 2010, 90 patients with psychiatric disorders (DSM-IV-TR) were randomized to IRT or treatment-as-usual conditions. IRT consisted of 6 individual sessions added to the treatment as usual. Nightmare frequency was assessed using daily nightmare logs and the Nightmare Frequency Questionnaire. Nightmare distress was assessed using the Nightmare Distress Questionnaire and the Nightmare Effects Survey. General psychiatric symptoms were assessed using the Symptom Checklist-90 and a PTSD symptom questionnaire. Assessments were administered at the start of the trial, after the IRT and at follow-up 3 months later. IRT showed a moderate effect (Cohen d = 0.5-0.7, P < .05) on nightmare frequency, nightmare distress, and psychopathology measures compared with treatment as usual. These effects were largely sustained at the 3-month follow-up (Cohen d = 0.4-0.6, P < .10). IRT is an effective treatment for nightmares among patients with comorbid psychiatric disorders and can be employed in addition to the on-going treatment. ClinicalTrials.gov identifier: NCT00291031. © Copyright 2015 Physicians Postgraduate Press, Inc.

Polarization of IRON-REGULATED TRANSPORTER 1 (IRT1) to the plant-soil interface plays crucial role in metal homeostasis.

PubMed

Barberon, Marie; Dubeaux, Guillaume; Kolb, Cornelia; Isono, Erika; Zelazny, Enric; Vert, Grégory

2014-06-03

In plants, the controlled absorption of soil nutrients by root epidermal cells is critical for growth and development. IRON-REGULATED TRANSPORTER 1 (IRT1) is the main root transporter taking up iron from the soil and is also the main entry route in plants for potentially toxic metals such as manganese, zinc, cobalt, and cadmium. Previous work demonstrated that the IRT1 protein localizes to early endosomes/trans-Golgi network (EE/TGN) and is constitutively endocytosed through a monoubiquitin- and clathrin-dependent mechanism. Here, we show that the availability of secondary non-iron metal substrates of IRT1 (Zn, Mn, and Co) controls the localization of IRT1 between the outer polar domain of the plasma membrane and EE/TGN in root epidermal cells. We also identify FYVE1, a phosphatidylinositol-3-phosphate-binding protein recruited to late endosomes, as an important regulator of IRT1-dependent metal transport and metal homeostasis in plants. FYVE1 controls IRT1 recycling to the plasma membrane and impacts the polar delivery of this transporter to the outer plasma membrane domain. This work establishes a functional link between the dynamics and the lateral polarity of IRT1 and the transport of its substrates, and identifies a molecular mechanism driving polar localization of a cell surface protein in plants.

Modeling Item-Position Effects within an IRT Framework

ERIC Educational Resources Information Center

Debeer, Dries; Janssen, Rianne

2013-01-01

Changing the order of items between alternate test forms to prevent copying and to enhance test security is a common practice in achievement testing. However, these changes in item order may affect item and test characteristics. Several procedures have been proposed for studying these item-order effects. The present study explores the use of…

The Sequential Probability Ratio Test and Binary Item Response Models

ERIC Educational Resources Information Center

Nydick, Steven W.

2014-01-01

The sequential probability ratio test (SPRT) is a common method for terminating item response theory (IRT)-based adaptive classification tests. To decide whether a classification test should stop, the SPRT compares a simple log-likelihood ratio, based on the classification bound separating two categories, to prespecified critical values. As has…

The use of immunochromatographic rapid test for soft tissue remains identification in order to distinguish between human and non-human origin.

PubMed

Gascho, Dominic; Morf, Nadja V; Thali, Michael J; Schaerli, Sarah

2017-05-01

Clear identification of soft tissue remains as being of non-human origin may be visually difficult in some cases e.g. due to decomposition. Thus, an additional examination is required. The use of an immunochromatographic rapid tests (IRT) device can be an easy solution with the additional advantage to be used directly at the site of discovery. The use of these test devices for detecting human blood at crime scenes is a common method. However, the IRT is specific not only for blood but also for differentiation between human and non-human soft tissue remains. In the following this method is discussed and validated by means of two forensic cases and several samples of various animals. Copyright © 2017 The Chartered Society of Forensic Sciences. Published by Elsevier B.V. All rights reserved.

Application of Item Response Theory to Tests of Substance-related Associative Memory

PubMed Central

Shono, Yusuke; Grenard, Jerry L.; Ames, Susan L.; Stacy, Alan W.

2015-01-01

A substance-related word association test (WAT) is one of the commonly used indirect tests of substance-related implicit associative memory and has been shown to predict substance use. This study applied an item response theory (IRT) modeling approach to evaluate psychometric properties of the alcohol- and marijuana-related WATs and their items among 775 ethnically diverse at-risk adolescents. After examining the IRT assumptions, item fit, and differential item functioning (DIF) across gender and age groups, the original 18 WAT items were reduced to 14- and 15-items in the alcohol- and marijuana-related WAT, respectively. Thereafter, unidimensional one- and two-parameter logistic models (1PL and 2PL models) were fitted to the revised WAT items. The results demonstrated that both alcohol- and marijuana-related WATs have good psychometric properties. These results were discussed in light of the framework of a unified concept of construct validity (Messick, 1975, 1989, 1995). PMID:25134051

The Effect of Repeaters on Equating

ERIC Educational Resources Information Center

Kim, HeeKyoung; Kolen, Michael J.

2010-01-01

Test equating might be affected by including in the equating analyses examinees who have taken the test previously. This study evaluated the effect of including such repeaters on Medical College Admission Test (MCAT) equating using a population invariance approach. Three-parameter logistic (3-PL) item response theory (IRT) true score and…

Using Unidimensional IRT Models for Dichotomous Classification via Computerized Classification Testing with Multidimensional Data.

ERIC Educational Resources Information Center

Lau, Che-Ming Allen; And Others

This study focused on the robustness of unidimensional item response theory (UIRT) models in computerized classification testing against violation of the unidimensionality assumption. The study addressed whether UIRT models remain acceptable under various testing conditions and dimensionality strengths. Monte Carlo simulation techniques were used…

Clinical vs. Self-report Versions of the Quick Inventory of Depressive Symptomatology in a Public Sector Sample

PubMed Central

Bernstein, Ira H.; Rush, A. John; Carmody, Thomas J.; Woo, Ada; Trivedi, Madhukar H.

2007-01-01

Objectives Recent work using classical test theory (CTT) and item response theory (IRT) has found that the self-report (QIDS-SR16) and clinician-rated (QIDS-C16) versions of the 16-item Quick Inventory of Depressive Symptomatology were generally comparable in outpatients with nonpsychotic major depressive disorder (MDD). This report extends this comparison to a less well-educated, more treatment-resistant sample that included more ethnic/racial minorities using IRT and selected classical test analyses. Methods The QIDS-SR16 and QIDS-C16 were obtained in a sample of 441 outpatients with nonpsychotic MDD seen in the public sector in the Texas Medication Algorithm Project (TMAP). The Samejima graded response IRT model was used to compare the QIDS-SR16 and QIDS-C16. Results The nine symptom domains in the QIDS-SR16 and QIDS-C16 related well to overall depression. The slopes of the item response functions a), which index the strength of relationship between overall depression and each symptom, were extremely similar with the two measures. Likewise, the CTT and IRT indices of symptom frequency (item means and locations of the item response functions, bi) were also similar with these two measures. For example, sad mood and difficulty with concentration/decision making were highly related to the overall depression severity with both the QIDS-C16 and QIDS-SR16. Likewise, sleeping difficulties were commonly reported, even though they were not as strongly related to overall magnitude of depression. Conclusion In this less educated, socially disadvantaged sample, differences between the QIDS-C16 and QIDS-SR16 were minor. The QIDS-SR16 is a satisfactory substitute for the more time-consuming QIDS-C16 in a broad range of adult, nonpsychotic, depressed outpatients. PMID:16716351

Clinical vs. self-report versions of the quick inventory of depressive symptomatology in a public sector sample.

PubMed

Bernstein, Ira H; Rush, A John; Carmody, Thomas J; Woo, Ada; Trivedi, Madhukar H

2007-01-01

Recent work using classical test theory (CTT) and item response theory (IRT) has found that the self-report (QIDS-SR(16)) and clinician-rated (QIDS-C(16)) versions of the 16-item quick inventory of depressive symptomatology were generally comparable in outpatients with nonpsychotic major depressive disorder (MDD). This report extends this comparison to a less well-educated, more treatment-resistant sample that included more ethnic/racial minorities using IRT and selected classical test analyses. The QIDS-SR(16) and QIDS-C(16) were obtained in a sample of 441 outpatients with nonpsychotic MDD seen in the public sector in the Texas Medication Algorithm Project (TMAP). The Samejima graded response IRT model was used to compare the QIDS-SR(16) and QIDS-C(16). The nine symptom domains in the QIDS-SR(16) and QIDS-C(16) related well to overall depression. The slopes of the item response functions, a, which index the strength of relationship between overall depression and each symptom, were extremely similar with the two measures. Likewise, the CTT and IRT indices of symptom frequency (item means and locations of the item response functions, b(i) were also similar with these two measures. For example, sad mood and difficulty with concentration/decision making were highly related to the overall depression severity with both the QIDS-C(16) and QIDS-SR(16). Likewise, sleeping difficulties were commonly reported, even though they were not as strongly related to overall magnitude of depression. In this less educated, socially disadvantaged sample, differences between the QIDS-C(16) and QIDS-SR(16) were minor. The QIDS-SR(16) is a satisfactory substitute for the more time-consuming QIDS-C(16) in a broad range of adult, nonpsychotic, depressed outpatients.

CF and School

MedlinePlus

... Testing for Cystic Fibrosis CFTR-Related Metabolic Syndrome (CRMS) How Babies Are Screened in IRT-Only vs. ... Guidelines Infant Care Clinical Care Guidelines Management of CRMS in First 2 Years and Beyond Clinical Care ...

About Cystic Fibrosis

MedlinePlus

... Testing for Cystic Fibrosis CFTR-Related Metabolic Syndrome (CRMS) How Babies Are Screened in IRT-Only vs. ... Guidelines Infant Care Clinical Care Guidelines Management of CRMS in First 2 Years and Beyond Clinical Care ...

Allergic Bronchopulmonary Aspergillosis

MedlinePlus

... Testing for Cystic Fibrosis CFTR-Related Metabolic Syndrome (CRMS) How Babies Are Screened in IRT-Only vs. ... Guidelines Infant Care Clinical Care Guidelines Management of CRMS in First 2 Years and Beyond Clinical Care ...

Lawton IADL scale in dementia: can item response theory make it more informative?

PubMed

McGrory, Sarah; Shenkin, Susan D; Austin, Elizabeth J; Starr, John M

2014-07-01

impairment of functional abilities represents a crucial component of dementia diagnosis. Current functional measures rely on the traditional aggregate method of summing raw scores. While this summary score provides a quick representation of a person's ability, it disregards useful information on the item level. to use item response theory (IRT) methods to increase the interpretive power of the Lawton Instrumental Activities of Daily Living (IADL) scale by establishing a hierarchy of item 'difficulty' and 'discrimination'. this cross-sectional study applied IRT methods to the analysis of IADL outcomes. Participants were 202 members of the Scottish Dementia Research Interest Register (mean age = 76.39, range = 56-93, SD = 7.89 years) with complete itemised data available. a Mokken scale with good reliability (Molenaar Sijtsama statistic 0.79) was obtained, satisfying the IRT assumption that the items comprise a single unidimensional scale. The eight items in the scale could be placed on a hierarchy of 'difficulty' (H coefficient = 0.55), with 'Shopping' being the most 'difficult' item and 'Telephone use' being the least 'difficult' item. 'Shopping' was the most discriminatory item differentiating well between patients of different levels of ability. IRT methods are capable of providing more information about functional impairment than a summed score. 'Shopping' and 'Telephone use' were identified as items that reveal key information about a patient's level of ability, and could be useful screening questions for clinicians. © The Author 2013. Published by Oxford University Press on behalf of the British Geriatrics Society. All rights reserved. For Permissions, please email: journals.permissions@ oup.com.

Going Places No Infrared Temperature Devices Have Gone Before

NASA Technical Reports Server (NTRS)

2003-01-01

Exergen's IRt/c is a self-powered sensor that matches a thermocouple within specified temperature ranges and provides a predictable and repeatable signal outside of this specified range. Possessing an extremely fast time constant, the infrared technology allows users to measure product temperature without touching the product. The IRt/c uses a device called a thermopile to measure temperature and generate current. Traditionally, these devices are not available in a size that would be compatible with the Exergen IRt/c, based on NASA s quarterinch specifications. After going through five circuit designs to find a thermopile that would suit the IRt/c design and match the signal needed for output, Exergen maintains that it developed a model that totaled just 20 percent of the volume of the previous smallest detector in the world. Following completion of the project with Glenn, Exergen continued development of the IRt/c for other customers, spinning off a new product line called the micro IRt/c. This latest development has broadened applications for industries that previously could not use infrared thermometers due to size constraints. The first commercial use of the micro IRt/c involved an original equipment manufacturer that makes laminating machinery consisting of heated rollers in very tight spots. Accurate temperature measurement for this application requires close proximity to the heated rollers. With the micro IRt/c s 50-millisecond time constant, the manufacturer is able to gain closer access to the intended temperature targets for exact readings, thereby increasing productivity and staying ahead of competition.In a separate application, the infrared temperature sensor is being utilized for avalanche warnings in Switzerland. The IRt/c is mounted about 5 meters above the ground to measure the snow cover throughout the mountainous regions of the country.

An Investigation of the Impact of Guessing on Coefficient α and Reliability

PubMed Central

2014-01-01

Guessing is known to influence the test reliability of multiple-choice tests. Although there are many studies that have examined the impact of guessing, they used rather restrictive assumptions (e.g., parallel test assumptions, homogeneous inter-item correlations, homogeneous item difficulty, and homogeneous guessing levels across items) to evaluate the relation between guessing and test reliability. Based on the item response theory (IRT) framework, this study investigated the extent of the impact of guessing on reliability under more realistic conditions where item difficulty, item discrimination, and guessing levels actually vary across items with three different test lengths (TL). By accommodating multiple item characteristics simultaneously, this study also focused on examining interaction effects between guessing and other variables entered in the simulation to be more realistic. The simulation of the more realistic conditions and calculations of reliability and classical test theory (CTT) item statistics were facilitated by expressing CTT item statistics, coefficient α, and reliability in terms of IRT model parameters. In addition to the general negative impact of guessing on reliability, results showed interaction effects between TL and guessing and between guessing and test difficulty.

Integration of optical measurement methods with flight parameter measurement systems

NASA Astrophysics Data System (ADS)

Kopecki, Grzegorz; Rzucidlo, Pawel

2016-05-01

During the AIM (advanced in-flight measurement techniques) and AIM2 projects, innovative modern techniques were developed. The purpose of the AIM project was to develop optical measurement techniques dedicated for flight tests. Such methods give information about aircraft elements deformation, thermal loads or pressure distribution, etc. In AIM2 the development of optical methods for flight testing was continued. In particular, this project aimed at the development of methods that could be easily applied in flight tests in an industrial setting. Another equally important task was to guarantee the synchronization of the classical measuring system with cameras. The PW-6U glider used in flight tests was provided by the Rzeszów University of Technology. The glider had all the equipment necessary for testing the IPCT (image pattern correlation technique) and IRT (infrared thermometry) methods. Additionally, equipment adequate for the measurement of typical flight parameters, registration and analysis has been developed. This article describes the designed system, as well as presenting the system’s application during flight tests. Additionally, the results obtained in flight tests show certain limitations of the IRT method as applied.

Remote sensing of multiple vital signs using a CMOS camera-equipped infrared thermography system and its clinical application in rapidly screening patients with suspected infectious diseases.

PubMed

Sun, Guanghao; Nakayama, Yosuke; Dagdanpurev, Sumiyakhand; Abe, Shigeto; Nishimura, Hidekazu; Kirimoto, Tetsuo; Matsui, Takemi

2017-02-01

Infrared thermography (IRT) is used to screen febrile passengers at international airports, but it suffers from low sensitivity. This study explored the application of a combined visible and thermal image processing approach that uses a CMOS camera equipped with IRT to remotely sense multiple vital signs and screen patients with suspected infectious diseases. An IRT system that produced visible and thermal images was used for image acquisition. The subjects' respiration rates were measured by monitoring temperature changes around the nasal areas on thermal images; facial skin temperatures were measured simultaneously. Facial blood circulation causes tiny color changes in visible facial images that enable the determination of the heart rate. A logistic regression discriminant function predicted the likelihood of infection within 10s, based on the measured vital signs. Sixteen patients with an influenza-like illness and 22 control subjects participated in a clinical test at a clinic in Fukushima, Japan. The vital-sign-based IRT screening system had a sensitivity of 87.5% and a negative predictive value of 91.7%; these values are higher than those of conventional fever-based screening approaches. Multiple vital-sign-based screening efficiently detected patients with suspected infectious diseases. It offers a promising alternative to conventional fever-based screening. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Measuring stigma after spinal cord injury: Development and psychometric characteristics of the SCI-QOL Stigma item bank and short form.

PubMed

Kisala, Pamela A; Tulsky, David S; Pace, Natalie; Victorson, David; Choi, Seung W; Heinemann, Allen W

2015-05-01

To develop a calibrated item bank and computer adaptive test (CAT) to assess the effects of stigma on health-related quality of life in individuals with spinal cord injury (SCI). Grounded-theory based qualitative item development methods, large-scale item calibration field testing, confirmatory factor analysis, and item response theory (IRT)-based psychometric analyses. Five SCI Model System centers and one Department of Veterans Affairs medical center in the United States. Adults with traumatic SCI. SCI-QOL Stigma Item Bank A sample of 611 individuals with traumatic SCI completed 30 items assessing SCI-related stigma. After 7 items were iteratively removed, factor analyses confirmed a unidimensional pool of items. Graded Response Model IRT analyses were used to estimate slopes and thresholds for the final 23 items. The SCI-QOL Stigma item bank is unique not only in the assessment of SCI-related stigma but also in the inclusion of individuals with SCI in all phases of its development. Use of confirmatory factor analytic and IRT methods provide flexibility and precision of measurement. The item bank may be administered as a CAT or as a 10-item fixed-length short form and can be used for research and clinical applications.

Measuring stigma after spinal cord injury: Development and psychometric characteristics of the SCI-QOL Stigma item bank and short form

PubMed Central

Kisala, Pamela A.; Tulsky, David S.; Pace, Natalie; Victorson, David; Choi, Seung W.; Heinemann, Allen W.

2015-01-01

Objective To develop a calibrated item bank and computer adaptive test (CAT) to assess the effects of stigma on health-related quality of life in individuals with spinal cord injury (SCI). Design Grounded-theory based qualitative item development methods, large-scale item calibration field testing, confirmatory factor analysis, and item response theory (IRT)-based psychometric analyses. Setting Five SCI Model System centers and one Department of Veterans Affairs medical center in the United States. Participants Adults with traumatic SCI. Main Outcome Measures SCI-QOL Stigma Item Bank Results A sample of 611 individuals with traumatic SCI completed 30 items assessing SCI-related stigma. After 7 items were iteratively removed, factor analyses confirmed a unidimensional pool of items. Graded Response Model IRT analyses were used to estimate slopes and thresholds for the final 23 items. Conclusions The SCI-QOL Stigma item bank is unique not only in the assessment of SCI-related stigma but also in the inclusion of individuals with SCI in all phases of its development. Use of confirmatory factor analytic and IRT methods provide flexibility and precision of measurement. The item bank may be administered as a CAT or as a 10-item fixed-length short form and can be used for research and clinical applications. PMID:26010973

Therapies for Cystic Fibrosis

MedlinePlus

... Testing for Cystic Fibrosis CFTR-Related Metabolic Syndrome (CRMS) How Babies Are Screened in IRT-Only vs. ... Guidelines Infant Care Clinical Care Guidelines Management of CRMS in First 2 Years and Beyond Clinical Care ...

Germs and Staying Healthy

MedlinePlus

... Testing for Cystic Fibrosis CFTR-Related Metabolic Syndrome (CRMS) How Babies Are Screened in IRT-Only vs. ... Guidelines Infant Care Clinical Care Guidelines Management of CRMS in First 2 Years and Beyond Clinical Care ...

Newborn Screening for CF

MedlinePlus

... Testing for Cystic Fibrosis CFTR-Related Metabolic Syndrome (CRMS) How Babies Are Screened in IRT-Only vs. ... Guidelines Infant Care Clinical Care Guidelines Management of CRMS in First 2 Years and Beyond Clinical Care ...

Using iRT, a normalized retention time for more targeted measurement of peptides

PubMed Central

Escher, Claudia; Reiter, Lukas; MacLean, Brendan; Ossola, Reto; Herzog, Franz; Chilton, John; MacCoss, Michael J.; Rinner, Oliver

2014-01-01

Multiple reaction monitoring (MRM) has recently become the method of choice for targeted quantitative measurement of proteins using mass spectrometry. The method, however, is limited in the number of peptides that can be measured in one run. This number can be markedly increased by scheduling the acquisition if the accurate retention time (RT) of each peptide is known. Here we present iRT, an empirically derived dimensionless peptide-specific value that allows for highly accurate RT prediction. The iRT of a peptide is a fixed number relative to a standard set of reference iRT-peptides that can be transferred across laboratories and chromatographic systems. We show that iRT facilitates the setup of multiplexed experiments with acquisition windows more than 4 times smaller compared to in silico RT predictions resulting in improved quantification accuracy. iRTs can be determined by any laboratory and shared transparently. The iRT concept has been implemented in Skyline, the most widely used software for MRM experiments. PMID:22577012

Local Labor Negotiations and the Urban Mass Transit Industry.

ERIC Educational Resources Information Center

Reed, Alan

1979-01-01

Examines the content of section 13-C of the Urban Mass Transportation Act of 1964, its role in labor negotiations at the local level, its impact on relations between local and national government, and the outcome of 13-C negotiations during the period 1975-77. (Author/IRT)

Flow Quality Surveys in the Settling Chamber of the NASA Glenn Icing Research Tunnel (2011 Tests)

NASA Technical Reports Server (NTRS)

Steen, Laura E.; Van Zante, Judith Foss; Broeren, Andy P.; Kubiak, Mark J.

2012-01-01

In 2011, the heat exchanger and refrigeration plant for NASA Glenn Research Center's Icing Research Tunnel (IRT) were upgraded. Flow quality surveys were performed in the settling chamber of the IRT in order to understand the effect that the new heat exchanger had on the flow quality upstream of the spray bars. Measurements were made of the total pressure, static pressure, total temperature, airspeed, and ow angle (pitch and yaw). These measurements were directly compared to measurements taken in 2000, after the previous heat exchanger was installed. In general, the flow quality appears to have improved with the new heat exchanger.

Flow Quality Surveys in the Settling Chamber of the NASA Glenn Icing Research Tunnel (2011 Tests)

NASA Technical Reports Server (NTRS)

Steen, Laura E.; VanZante, Judith Foss; Broeren, Andy P.; Kubiak, Mark J.

2012-01-01

In 2011, the heat exchanger and refrigeration plant for NASA Glenn Research Center's Icing Research Tunnel (IRT) were upgraded. Flow quality surveys were performed in the settling chamber of the IRT in order to understand the effect that the new heat exchanger had on the flow quality upstream of the spray bars. Measurements were made of the total pressure, static pressure, total temperature, airspeed, and flow angle (pitch and yaw). These measurements were directly compared to measurements taken in 2000, after the previous heat exchanger was installed. In general, the flow quality appears to have improved with the new heat exchanger.

Flow Quality Surveys in the Settling Chamber of the NASA Glenn Icing Research Tunnel (2011 Tests)

NASA Technical Reports Server (NTRS)

Steen, Laura E.; VanZante, Judith Foss; Broeren, Andy P.; Kubiak, Mark J.

2014-01-01

In 2011, the heat exchanger and refrigeration plant for NASA Glenn Research Centers Icing Research Tunnel (IRT) were upgraded. Flow quality surveys were performed in the settling chamber of the IRT in order to understand the effect that the new heat exchanger had on the flow quality upstream of the spray bars. Measurements were made of the total pressure, static pressure, total temperature, airspeed, and flow angle (pitch and yaw). These measurements were directly compared to measurements taken in 2000, after the previous heat exchanger was installed. In general, the flow quality appears to have improved with the new heat exchanger.

NOD promoter-controlled AtIRT1 expression functions synergistically with NAS and FERRITIN genes to increase iron in rice grains.

PubMed

Boonyaves, Kulaporn; Gruissem, Wilhelm; Bhullar, Navreet K

2016-02-01

Rice is a staple food for over half of the world's population, but it contains only low amounts of bioavailable micronutrients for human nutrition. Consequently, micronutrient deficiency is a widespread health problem among people who depend primarily on rice as their staple food. Iron deficiency anemia is one of the most serious forms of malnutrition. Biofortification of rice grains for increased iron content is an effective strategy to reduce iron deficiency. Unlike other grass species, rice takes up iron as Fe(II) via the IRON REGULATED TRANSPORTER (IRT) in addition to Fe(III)-phytosiderophore chelates. We expressed Arabidopsis IRT1 (AtIRT1) under control of the Medicago sativa EARLY NODULIN 12B promoter in our previously developed high-iron NFP rice lines expressing NICOTIANAMINE SYNTHASE (AtNAS1) and FERRITIN. Transgenic rice lines expressing AtIRT1 alone had significant increases in iron and combined with NAS and FERRITIN increased iron to 9.6 µg/g DW in the polished grains that is 2.2-fold higher as compared to NFP lines. The grains of AtIRT1 lines also accumulated more copper and zinc but not manganese. Our results demonstrate that the concerted expression of AtIRT1, AtNAS1 and PvFERRITIN synergistically increases iron in both polished and unpolished rice grains. AtIRT1 is therefore a valuable transporter for iron biofortification programs when used in combination with other genes encoding iron transporters and/or storage proteins.

Investigation of water droplet trajectories within the NASA icing research tunnel

NASA Technical Reports Server (NTRS)

Reehorst, Andrew; Ibrahim, Mounir

1995-01-01

Water droplet trajectories within the NASA Lewis Research Center's Icing Research Tunnel (IRT) were studied through computer analysis. Of interest was the influence of the wind tunnel contraction and wind tunnel model blockage on the water droplet trajectories. The computer analysis was carried out with a program package consisting of a three-dimensional potential panel code and a three-dimensional droplet trajectory code. The wind tunnel contraction was found to influence the droplet size distribution and liquid water content distribution across the test section from that at the inlet. The wind tunnel walls were found to have negligible influence upon the impingement of water droplets upon a wing model.

Methicillin-Resistant Staphylococcus aureus (MRSA)

MedlinePlus

... Testing for Cystic Fibrosis CFTR-Related Metabolic Syndrome (CRMS) How Babies Are Screened in IRT-Only vs. ... Guidelines Infant Care Clinical Care Guidelines Management of CRMS in First 2 Years and Beyond Clinical Care ...

Conditional Standard Errors of Measurement for Composite Scores Using IRT

ERIC Educational Resources Information Center

Kolen, Michael J.; Wang, Tianyou; Lee, Won-Chan

2012-01-01

Composite scores are often formed from test scores on educational achievement test batteries to provide a single index of achievement over two or more content areas or two or more item types on that test. Composite scores are subject to measurement error, and as with scores on individual tests, the amount of error variability typically depends on…

A Person Fit Test for IRT Models for Polytomous Items

ERIC Educational Resources Information Center

Glas, C. A. W.; Dagohoy, Anna Villa T.

2007-01-01

A person fit test based on the Lagrange multiplier test is presented for three item response theory models for polytomous items: the generalized partial credit model, the sequential model, and the graded response model. The test can also be used in the framework of multidimensional ability parameters. It is shown that the Lagrange multiplier…

An Explanatory Item Response Theory Approach for a Computer-Based Case Simulation Test

ERIC Educational Resources Information Center

Kahraman, Nilüfer

2014-01-01

Problem: Practitioners working with multiple-choice tests have long utilized Item Response Theory (IRT) models to evaluate the performance of test items for quality assurance. The use of similar applications for performance tests, however, is often encumbered due to the challenges encountered in working with complicated data sets in which local…

Differential Item Functioning: Its Consequences. Research Report. ETS RR-10-01

ERIC Educational Resources Information Center

Lee, Yi-Hsuan; Zhang, Jinming

2010-01-01

This report examines the consequences of differential item functioning (DIF) using simulated data. Its impact on total score, item response theory (IRT) ability estimate, and test reliability was evaluated in various testing scenarios created by manipulating the following four factors: test length, percentage of DIF items per form, sample sizes of…

Psychometric Properties of the Revised Purdue Spatial Visualization Tests: Visualization of Rotations (The Revised PSVT-R)

ERIC Educational Resources Information Center

Yoon, So Yoon

2011-01-01

Working under classical test theory (CTT) and item response theory (IRT) frameworks, this study investigated psychometric properties of the Revised Purdue Spatial Visualization Tests: Visualization of Rotations (Revised PSVT:R). The original version, the PSVT:R was designed by Guay (1976) to measure spatial visualization ability in…

Development and Validation of a Computer Adaptive EFL Test

ERIC Educational Resources Information Center

He, Lianzhen; Min, Shangchao

2017-01-01

The first aim of this study was to develop a computer adaptive EFL test (CALT) that assesses test takers' listening and reading proficiency in English with dichotomous items and polytomous testlets. We reported in detail on the development of the CALT, including item banking, determination of suitable item response theory (IRT) models for item…

Ice Accretion with Varying Surface Tension

NASA Technical Reports Server (NTRS)

Bilanin, Alan J.; Anderson, David N.

1995-01-01

During an icing encounter of an aircraft in flight, super-cooled water droplets impinging on an airfoil may splash before freezing. This paper reports tests performed to determine if this effect is significant and uses the results to develop an improved scaling method for use in icing test facilities. Simple laboratory tests showed that drops splash on impact at the Reynolds and Weber numbers typical of icing encounters. Further confirmation of droplet splash came from icing tests performed in the NaSA Lewis Icing Research Tunnel (IRT) with a surfactant added to the spray water to reduce the surface tension. The resulting ice shapes were significantly different from those formed when no surfactant was added to the water. These results suggested that the droplet Weber number must be kept constant to properly scale icing test conditions. Finally, the paper presents a Weber-number-based scaling method and reports results from scaling tests in the IRT in which model size was reduced up to a factor of 3. Scale and reference ice shapes are shown which confirm the effectiveness of this new scaling method.

Do Concept Inventories Actually Measure Anything?

ERIC Educational Resources Information Center

Wallace, Colin S.; Bailey, Janelle M.

2010-01-01

Although concept inventories are among the most frequently used tools in the physics and astronomy education communities, they are rarely evaluated using item response theory (IRT). When IRT models fit the data, they offer sample-independent estimates of item and person parameters. IRT may also provide a way to measure students' learning gains…

Infrared thermography for condition monitoring - A review

NASA Astrophysics Data System (ADS)

Bagavathiappan, S.; Lahiri, B. B.; Saravanan, T.; Philip, John; Jayakumar, T.

2013-09-01

Temperature is one of the most common indicators of the structural health of equipment and components. Faulty machineries, corroded electrical connections, damaged material components, etc., can cause abnormal temperature distribution. By now, infrared thermography (IRT) has become a matured and widely accepted condition monitoring tool where the temperature is measured in real time in a non-contact manner. IRT enables early detection of equipment flaws and faulty industrial processes under operating condition thereby, reducing system down time, catastrophic breakdown and maintenance cost. Last three decades witnessed a steady growth in the use of IRT as a condition monitoring technique in civil structures, electrical installations, machineries and equipment, material deformation under various loading conditions, corrosion damages and welding processes. IRT has also found its application in nuclear, aerospace, food, paper, wood and plastic industries. With the advent of newer generations of infrared camera, IRT is becoming a more accurate, reliable and cost effective technique. This review focuses on the advances of IRT as a non-contact and non-invasive condition monitoring tool for machineries, equipment and processes. Various conditions monitoring applications are discussed in details, along with some basics of IRT, experimental procedures and data analysis techniques. Sufficient background information is also provided for the beginners and non-experts for easy understanding of the subject.

Effects of eight weeks of aerobic interval training and of isoinertial resistance training on risk factors of cardiometabolic diseases and exercise capacity in healthy elderly subjects

PubMed Central

Bruseghini, Paolo; Calabria, Elisa; Tam, Enrico; Milanese, Chiara; Oliboni, Eugenio; Pezzato, Andrea; Pogliaghi, Silvia; Salvagno, Gian Luca; Schena, Federico; Mucelli, Roberto Pozzi; Capelli, Carlo

2015-01-01

We investigated the effect of 8 weeks of high intensity interval training (HIT) and isoinertial resistance training (IRT) on cardiovascular fitness, muscle mass-strength and risk factors of metabolic syndrome in 12 healthy older adults (68 yy ± 4). HIT consisted in 7 two-minute repetitions at 80%–90% of V˙O2max, 3 times/w. After 4 months of recovery, subjects were treated with IRT, which included 4 sets of 7 maximal, bilateral knee extensions/flexions 3 times/w on a leg-press flywheel ergometer. HIT elicited significant: i) modifications of selected anthropometrical features; ii) improvements of cardiovascular fitness and; iii) decrease of systolic pressure. HIT and IRT induced hypertrophy of the quadriceps muscle, which, however, was paralleled by significant increases in strength only after IRT. Neither HIT nor IRT induced relevant changes in blood lipid profile, with the exception of a decrease of LDL and CHO after IRT. Physiological parameters related with aerobic fitness and selected body composition values predicting cardiovascular risk remained stable during detraining and, after IRT, they were complemented by substantial increase of muscle strength, leading to further improvements of quality of life of the subjects. PMID:26046575

Effects of instability versus traditional resistance training on strength, power and velocity in untrained men.

PubMed

Maté-Muñoz, José Luis; Monroy, Antonio J Antón; Jodra Jiménez, Pablo; Garnacho-Castaño, Manuel V

2014-09-01

The purpose of this study was compare the effects of a traditional and an instability resistance circuit training program on upper and lower limb strength, power, movement velocity and jumping ability. Thirty-six healthy untrained men were assigned to two experimental groups and a control group. Subjects in the experimental groups performed a resistance circuit training program consisting of traditional exercises (TRT, n = 10) or exercises executed in conditions of instability (using BOSU® and TRX®) (IRT, n = 12). Both programs involved three days per week of training for a total of seven weeks. The following variables were determined before and after training: maximal strength (1RM), average (AV) and peak velocity (PV), average (AP) and peak power (PP), all during bench press (BP) and back squat (BS) exercises, along with squat jump (SJ) height and counter movement jump (CMJ) height. All variables were found to significantly improve (p <0.05) in response to both training programs. Major improvements were observed in SJ height (IRT = 22.1%, TRT = 20.1%), CMJ height (IRT = 17.7%, TRT = 15.2%), 1RM in BS (IRT = 13.03%, TRT = 12.6%), 1RM in BP (IRT = 4.7%, TRT = 4.4%), AP in BS (IRT = 10.5%, TRT = 9.3%), AP in BP (IRT = 2.4%, TRT = 8.1%), PP in BS (IRT=19.42%, TRT = 22.3%), PP in BP (IRT = 7.6%, TRT = 11.5%), AV in BS (IRT = 10.5%, TRT = 9.4%), and PV in BS (IRT = 8.6%, TRT = 4.5%). Despite such improvements no significant differences were detected in the posttraining variables recorded for the two experimental groups. These data indicate that a circuit training program using two instability training devices is as effective in untrained men as a program executed under stable conditions for improving strength (1RM), power, movement velocity and jumping ability. Key PointsSimilar adaptations in terms of gains in strength, power, movement velocity and jumping ability were produced in response to both training programs.Both the stability and instability approaches seem suitable for healthy, physically-active individuals with or with limited experience in resistance training.RPE emerged as a useful tool to monitor exercise intensity during instability strength training.

Effects of Instability Versus Traditional Resistance Training on Strength, Power and Velocity in Untrained Men

PubMed Central

Maté-Muñoz, José Luis; Monroy, Antonio J. Antón; Jodra Jiménez, Pablo; Garnacho-Castaño, Manuel V.

2014-01-01

The purpose of this study was compare the effects of a traditional and an instability resistance circuit training program on upper and lower limb strength, power, movement velocity and jumping ability. Thirty-six healthy untrained men were assigned to two experimental groups and a control group. Subjects in the experimental groups performed a resistance circuit training program consisting of traditional exercises (TRT, n = 10) or exercises executed in conditions of instability (using BOSU® and TRX®) (IRT, n = 12). Both programs involved three days per week of training for a total of seven weeks. The following variables were determined before and after training: maximal strength (1RM), average (AV) and peak velocity (PV), average (AP) and peak power (PP), all during bench press (BP) and back squat (BS) exercises, along with squat jump (SJ) height and counter movement jump (CMJ) height. All variables were found to significantly improve (p <0.05) in response to both training programs. Major improvements were observed in SJ height (IRT = 22.1%, TRT = 20.1%), CMJ height (IRT = 17.7%, TRT = 15.2%), 1RM in BS (IRT = 13.03%, TRT = 12.6%), 1RM in BP (IRT = 4.7%, TRT = 4.4%), AP in BS (IRT = 10.5%, TRT = 9.3%), AP in BP (IRT = 2.4%, TRT = 8.1%), PP in BS (IRT=19.42%, TRT = 22.3%), PP in BP (IRT = 7.6%, TRT = 11.5%), AV in BS (IRT = 10.5%, TRT = 9.4%), and PV in BS (IRT = 8.6%, TRT = 4.5%). Despite such improvements no significant differences were detected in the posttraining variables recorded for the two experimental groups. These data indicate that a circuit training program using two instability training devices is as effective in untrained men as a program executed under stable conditions for improving strength (1RM), power, movement velocity and jumping ability. Key Points Similar adaptations in terms of gains in strength, power, movement velocity and jumping ability were produced in response to both training programs. Both the stability and instability approaches seem suitable for healthy, physically-active individuals with or with limited experience in resistance training. RPE emerged as a useful tool to monitor exercise intensity during instability strength training. PMID:25177170

The Effects of Test Length and Sample Size on Item Parameters in Item Response Theory

ERIC Educational Resources Information Center

Sahin, Alper; Anil, Duygu

2017-01-01

This study investigates the effects of sample size and test length on item-parameter estimation in test development utilizing three unidimensional dichotomous models of item response theory (IRT). For this purpose, a real language test comprised of 50 items was administered to 6,288 students. Data from this test was used to obtain data sets of…

Unidimensional IRT Item Parameter Estimates across Equivalent Test Forms with Confounding Specifications within Dimensions

ERIC Educational Resources Information Center

Matlock, Ki Lynn; Turner, Ronna

2016-01-01

When constructing multiple test forms, the number of items and the total test difficulty are often equivalent. Not all test developers match the number of items and/or average item difficulty within subcontent areas. In this simulation study, six test forms were constructed having an equal number of items and average item difficulty overall.…

Differential item functioning analysis with ordinal logistic regression techniques. DIFdetect and difwithpar.

PubMed

Crane, Paul K; Gibbons, Laura E; Jolley, Lance; van Belle, Gerald

2006-11-01

We present an ordinal logistic regression model for identification of items with differential item functioning (DIF) and apply this model to a Mini-Mental State Examination (MMSE) dataset. We employ item response theory ability estimation in our models. Three nested ordinal logistic regression models are applied to each item. Model testing begins with examination of the statistical significance of the interaction term between ability and the group indicator, consistent with nonuniform DIF. Then we turn our attention to the coefficient of the ability term in models with and without the group term. If including the group term has a marked effect on that coefficient, we declare that it has uniform DIF. We examined DIF related to language of test administration in addition to self-reported race, Hispanic ethnicity, age, years of education, and sex. We used PARSCALE for IRT analyses and STATA for ordinal logistic regression approaches. We used an iterative technique for adjusting IRT ability estimates on the basis of DIF findings. Five items were found to have DIF related to language. These same items also had DIF related to other covariates. The ordinal logistic regression approach to DIF detection, when combined with IRT ability estimates, provides a reasonable alternative for DIF detection. There appear to be several items with significant DIF related to language of test administration in the MMSE. More attention needs to be paid to the specific criteria used to determine whether an item has DIF, not just the technique used to identify DIF.

Additional Results of Glaze Icing Scaling in SLD Conditions

NASA Technical Reports Server (NTRS)

Tsao, Jen-Ching

2016-01-01

New guidance of acceptable means of compliance with the super-cooled large drops (SLD) conditions has been issued by the U.S. Department of Transportation's Federal Aviation Administration (FAA) in its Advisory Circular AC 25-28 in November 2014. The Part 25, Appendix O is developed to define a representative icing environment for super-cooled large drops. Super-cooled large drops, which include freezing drizzle and freezing rain conditions, are not included in Appendix C. This paper reports results from recent glaze icing scaling tests conducted in NASA Glenn Icing Research Tunnel (IRT) to evaluate how well the scaling methods recommended for Appendix C conditions might apply to SLD conditions. The models were straight NACA 0012 wing sections. The reference model had a chord of 72 inches and the scale model had a chord of 21 inches. Reference tests were run with airspeeds of 100 and 130.3 knots and with MVD's of 85 and 170 microns. Two scaling methods were considered. One was based on the modified Ruff method with scale velocity found by matching the Weber number W (sub eL). The other was proposed and developed by Feo specifically for strong glaze icing conditions, in which the scale liquid water content and velocity were found by matching reference and scale values of the non-dimensional water-film thickness expression and the film Weber number W (sub ef). All tests were conducted at 0 degrees angle of arrival. Results will be presented for stagnation freezing fractions of 0.2 and 0.3. For non-dimensional reference and scale ice shape comparison, a new post-scanning ice shape digitization procedure was developed for extracting 2-dimensional ice shape profiles at any selected span-wise location from the high fidelity 3-dimensional scanned ice shapes obtained in the IRT.

Additional Results of Glaze Icing Scaling in SLD Conditions

NASA Technical Reports Server (NTRS)

Tsao, Jen-Ching

2016-01-01

New guidance of acceptable means of compliance with the super-cooled large drops (SLD) conditions has been issued by the U.S. Department of Transportation's Federal Aviation Administration (FAA) in its Advisory Circular AC 25-28 in November 2014. The Part 25, Appendix O is developed to define a representative icing environment for super-cooled large drops. Super-cooled large drops, which include freezing drizzle and freezing rain conditions, are not included in Appendix C. This paper reports results from recent glaze icing scaling tests conducted in NASA Glenn Icing Research Tunnel (IRT) to evaluate how well the scaling methods recommended for Appendix C conditions might apply to SLD conditions. The models were straight NACA 0012 wing sections. The reference model had a chord of 72 in. and the scale model had a chord of 21 in. Reference tests were run with airspeeds of 100 and 130.3 kn and with MVD's of 85 and 170 micron. Two scaling methods were considered. One was based on the modified Ruff method with scale velocity found by matching the Weber number WeL. The other was proposed and developed by Feo specifically for strong glaze icing conditions, in which the scale liquid water content and velocity were found by matching reference and scale values of the nondimensional water-film thickness expression and the film Weber number Wef. All tests were conducted at 0 deg AOA. Results will be presented for stagnation freezing fractions of 0.2 and 0.3. For nondimensional reference and scale ice shape comparison, a new post-scanning ice shape digitization procedure was developed for extracting 2-D ice shape profiles at any selected span-wise location from the high fidelity 3-D scanned ice shapes obtained in the IRT.

An IRT Model with a Parameter-Driven Process for Change

ERIC Educational Resources Information Center

Rijmen, Frank; De Boeck, Paul; van der Maas, Han L. J.

2005-01-01

An IRT model with a parameter-driven process for change is proposed. Quantitative differences between persons are taken into account by a continuous latent variable, as in common IRT models. In addition, qualitative inter-individual differences and auto-dependencies are accounted for by assuming within-subject variability with respect to the…

Practical Issues in Estimating Classification Accuracy and Consistency with R Package cacIRT

ERIC Educational Resources Information Center

Lathrop, Quinn N.

2015-01-01

There are two main lines of research in estimating classification accuracy (CA) and classification consistency (CC) under Item Response Theory (IRT). The R package cacIRT provides computer implementations of both approaches in an accessible and unified framework. Even with available implementations, there remains decisions a researcher faces when…

IRT-Stimulus Contingencies in Chained Schedules: Implications for the Concept of Conditioned Reinforcement

ERIC Educational Resources Information Center

Bejarano, Rafael; Hackenberg, Timothy D.

2007-01-01

Two experiments with pigeons investigated the effects of contingencies between interresponse times (IRTs) and the transitions between the components of 2- and 4-component chained schedules (Experiments 1 and 2, respectively). The probability of component transitions varied directly with the most recent (Lag 0) IRT in some experimental conditions…

Item Response Theory with Estimation of the Latent Density Using Davidian Curves

ERIC Educational Resources Information Center

Woods, Carol M.; Lin, Nan

2009-01-01

Davidian-curve item response theory (DC-IRT) is introduced, evaluated with simulations, and illustrated using data from the Schedule for Nonadaptive and Adaptive Personality Entitlement scale. DC-IRT is a method for fitting unidimensional IRT models with maximum marginal likelihood estimation, in which the latent density is estimated,…

Item Response Theory: A Basic Concept

ERIC Educational Resources Information Center

Mahmud, Jumailiyah

2017-01-01

With the development in computing technology, item response theory (IRT) develops rapidly, and has become a user friendly application in psychometrics world. Limitation in classical theory is one aspect that encourages the use of IRT. In this study, the basic concept of IRT will be discussed. In addition, it will briefly review the ability…

IRTPRO 2.1 for Windows (Item Response Theory for Patient-Reported Outcomes)

ERIC Educational Resources Information Center

Paek, Insu; Han, Kyung T.

2013-01-01

This article reviews a new item response theory (IRT) model estimation program, IRTPRO 2.1, for Windows that is capable of unidimensional and multidimensional IRT model estimation for existing and user-specified constrained IRT models for dichotomously and polytomously scored item response data. (Contains 1 figure and 2 notes.)

Using iRT, a normalized retention time for more targeted measurement of peptides.

PubMed

Escher, Claudia; Reiter, Lukas; MacLean, Brendan; Ossola, Reto; Herzog, Franz; Chilton, John; MacCoss, Michael J; Rinner, Oliver

2012-04-01

Multiple reaction monitoring (MRM) has recently become the method of choice for targeted quantitative measurement of proteins using mass spectrometry. The method, however, is limited in the number of peptides that can be measured in one run. This number can be markedly increased by scheduling the acquisition if the accurate retention time (RT) of each peptide is known. Here we present iRT, an empirically derived dimensionless peptide-specific value that allows for highly accurate RT prediction. The iRT of a peptide is a fixed number relative to a standard set of reference iRT-peptides that can be transferred across laboratories and chromatographic systems. We show that iRT facilitates the setup of multiplexed experiments with acquisition windows more than four times smaller compared to in silico RT predictions resulting in improved quantification accuracy. iRTs can be determined by any laboratory and shared transparently. The iRT concept has been implemented in Skyline, the most widely used software for MRM experiments. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Monitoring Items in Real Time to Enhance CAT Security

ERIC Educational Resources Information Center

Zhang, Jinming; Li, Jie

2016-01-01

An IRT-based sequential procedure is developed to monitor items for enhancing test security. The procedure uses a series of statistical hypothesis tests to examine whether the statistical characteristics of each item under inspection have changed significantly during CAT administration. This procedure is compared with a previously developed…

Ramsay-Curve Differential Item Functioning

ERIC Educational Resources Information Center

Woods, Carol M.

2011-01-01

Differential item functioning (DIF) occurs when an item on a test, questionnaire, or interview has different measurement properties for one group of people versus another, irrespective of true group-mean differences on the constructs being measured. This article is focused on item response theory based likelihood ratio testing for DIF (IRT-LR or…

The Long-Term Sustainability of Different Item Response Theory Scaling Methods

ERIC Educational Resources Information Center

Keller, Lisa A.; Keller, Robert R.

2011-01-01

This article investigates the accuracy of examinee classification into performance categories and the estimation of the theta parameter for several item response theory (IRT) scaling techniques when applied to six administrations of a test. Previous research has investigated only two administrations; however, many testing programs equate tests…

Computerized Adaptive Testing: Some Issues in Development.

ERIC Educational Resources Information Center

Orcutt, Venetia L.

The emergence of enhanced capabilities in computer technology coupled with the growing body of knowledge regarding item response theory has resulted in the expansion of computerized adaptive test (CAT) utilization in a variety of venues. Newcomers to the field need a more thorough understanding of item response theory (IRT) principles, their…

Salient Features of the Harnischfeger-Wiley Model

ERIC Educational Resources Information Center

Hallinan, Maureen T.

1976-01-01

Explicates the Harnischfeger-Wiley model and points out its properties, underlying assumptions, and location in the literature on achievement. It also describes and critiques an empirical test by Harnischfeger and Wiley of their model. (Author/IRT)

Short Assessment of Health Literacy—Spanish and English: A Comparable Test of Health Literacy for Spanish and English Speakers

PubMed Central

Lee, Shoou-Yih Daniel; Stucky, Brian D; Lee, Jessica Y; Rozier, R Gary; Bender, Deborah E

2010-01-01

Objective The intent of the study was to develop and validate a comparable health literacy test for Spanish-speaking and English-speaking populations. Study Design The design of the instrument, named the Short Assessment of Health Literacy—Spanish and English (SAHL-S&E), combined a word recognition test, as appearing in the Rapid Estimate of Adult Literacy in Medicine (REALM), and a comprehension test using multiple-choice questions designed by an expert panel. We used the item response theory (IRT) in developing and validating the instrument. Data Collection Validation of SAHL-S&E involved testing and comparing the instrument with other health literacy instruments in a sample of 201 Spanish-speaking and 202 English-speaking subjects recruited from the Ambulatory Care Center at the University of North Carolina Healthcare System. Principal Findings Based on IRT analysis, 18 items were retained in the comparable test. The Spanish version of the test, SAHL-S, was highly correlated with other Spanish health literacy instruments, Short Assessment of Health Literacy for Spanish-Speaking Adults (r=0.88, p<.05) and the Spanish Test of Functional Health Literacy in Adults (TOFHLA) (r=0.62, p<.05). The English version, SAHL-E, had high correlations with REALM (r=0.94, p<.05) and the English TOFHLA (r=0.68, p<.05). Significant correlations were found between SAHL-S&E and years of schooling in both Spanish- and English-speaking samples (r=0.15 and 0.39, respectively). SAHL-S&E displayed satisfactory reliability of 0.80 and 0.89 in the Spanish- and English-speaking samples, respectively. IRT analysis indicated that the SAHL-S&E score was highly reliable for individuals with a low level of health literacy. Conclusions The new instrument, SAHL-S&E, has good reliability and validity. It is particularly useful for identifying individuals with low health literacy and could be used to screen for low health literacy among Spanish and English speakers. PMID:20500222

Item Response Theory Models for Performance Decline during Testing

ERIC Educational Resources Information Center

Jin, Kuan-Yu; Wang, Wen-Chung

2014-01-01

Sometimes, test-takers may not be able to attempt all items to the best of their ability (with full effort) due to personal factors (e.g., low motivation) or testing conditions (e.g., time limit), resulting in poor performances on certain items, especially those located toward the end of a test. Standard item response theory (IRT) models fail to…

Comparing and Combining Dichotomous and Polytomous Items with SPRT Procedure in Computerized Classification Testing.

ERIC Educational Resources Information Center

Lau, C. Allen; Wang, Tianyou

The purposes of this study were to: (1) extend the sequential probability ratio testing (SPRT) procedure to polytomous item response theory (IRT) models in computerized classification testing (CCT); (2) compare polytomous items with dichotomous items using the SPRT procedure for their accuracy and efficiency; (3) study a direct approach in…

An Approach to Scoring and Equating Tests with Binary Items: Piloting With Large-Scale Assessments

ERIC Educational Resources Information Center

Dimitrov, Dimiter M.

2016-01-01

This article describes an approach to test scoring, referred to as "delta scoring" (D-scoring), for tests with dichotomously scored items. The D-scoring uses information from item response theory (IRT) calibration to facilitate computations and interpretations in the context of large-scale assessments. The D-score is computed from the…

Generalization of the Lord-Wingersky Algorithm to Computing the Distribution of Summed Test Scores Based on Real-Number Item Scores

ERIC Educational Resources Information Center

Kim, Seonghoon

2013-01-01

With known item response theory (IRT) item parameters, Lord and Wingersky provided a recursive algorithm for computing the conditional frequency distribution of number-correct test scores, given proficiency. This article presents a generalized algorithm for computing the conditional distribution of summed test scores involving real-number item…

When Cognitive Diagnosis Meets Computerized Adaptive Testing: CD-CAT

ERIC Educational Resources Information Center

Cheng, Ying

2009-01-01

Computerized adaptive testing (CAT) is a mode of testing which enables more efficient and accurate recovery of one or more latent traits. Traditionally, CAT is built upon Item Response Theory (IRT) models that assume unidimensionality. However, the problem of how to build CAT upon latent class models (LCM) has not been investigated until recently,…

Model Choice and Sample Size in Item Response Theory Analysis of Aphasia Tests

ERIC Educational Resources Information Center

Hula, William D.; Fergadiotis, Gerasimos; Martin, Nadine

2012-01-01

Purpose: The purpose of this study was to identify the most appropriate item response theory (IRT) measurement model for aphasia tests requiring 2-choice responses and to determine whether small samples are adequate for estimating such models. Method: Pyramids and Palm Trees (Howard & Patterson, 1992) test data that had been collected from…

Lord's Wald Test for Detecting Dif in Multidimensional Irt Models: A Comparison of Two Estimation Approaches

ERIC Educational Resources Information Center

Lee, Soo; Suh, Youngsuk

2018-01-01

Lord's Wald test for differential item functioning (DIF) has not been studied extensively in the context of the multidimensional item response theory (MIRT) framework. In this article, Lord's Wald test was implemented using two estimation approaches, marginal maximum likelihood estimation and Bayesian Markov chain Monte Carlo estimation, to detect…

Convective heat transfer measurements from a NACA 0012 airfoil in flight and in the NASA Lewis Icing Research Tunnel

NASA Technical Reports Server (NTRS)

Poinsatte, Philip E.; Vanfossen, G. James; Dewitt, Kenneth J.

1989-01-01

Local heat transfer coefficients were measured on a smooth and roughened NACA 0012 airfoil. Heat transfer measurements on the 0.533 m chord airfoil were made both in flight on the NASA Lewis Twin Otter Icing Research Aircraft and in the NASA Lewis Icing Research Tunnel (IRT). Roughness was obtained by the attachment of uniform 2 mm diameter hemispheres to the airfoil surface in 4 distinct patterns. Flight data were taken for the smooth and roughened airfoil at various Reynolds numbers based on chord in the range 1.24 to 2.50 x 10(exp 6) and at various angles of attack up to 4 deg. During these flight tests, the free stream velocity turbulence intensity was found to be very low (less than 0.1 percent). Wind tunnel data were acquired in the Reynolds number range 1.20 to 4.25 x 10(exp 6) and at angles of attack from -4 to 8 deg. The turbulence intensity in the IRT was 0.5 to 0.7 percent with the cloud generating sprays off. A direct comparison was made between the results obtained in flight and in the IRT. The higher level of turbulence in the IRT vs. flight had little effect on the heat transfer for the lower Reynolds numbers but caused a moderate increase in heat transfer at the high Reynolds numbers. Roughness generally increased the heat transfer.

Scale Refinement and Initial Evaluation of a Behavioral Health Function Measurement Tool for Work Disability Evaluation

PubMed Central

Marfeo, Elizabeth E.; Ni, Pengsheng; Bogusz, Kara; Meterko, Mark; McDonough, Christine M.; Chan, Leighton; Rasch, Elizabeth K.; Brandt, Diane E.; Jette, Alan M.

2014-01-01

Objectives To use item response theory (IRT) data simulations to construct and perform initial psychometric testing of a newly developed instrument, the Social Security Administration Behavioral Health Function (SSA-BH) instrument, that aims to assess behavioral health functioning relevant to the context of work. Design Cross-sectional survey followed by item response theory (IRT) calibration data simulations Setting Community Participants A sample of individuals applying for SSA disability benefits, claimants (N=1015), and a normative comparative sample of US adults (N=1000) Interventions None. Main Outcome Measure Social Security Administration Behavioral Health Function (SSA-BH) measurement instrument Results Item response theory analyses supported the unidimensionality of four SSA-BH scales: Mood and Emotions (35 items), Self-Efficacy (23 items), Social Interactions (6 items), and Behavioral Control (15 items). All SSA-BH scales demonstrated strong psychometric properties including reliability, accuracy, and breadth of coverage. High correlations of the simulated 5- or 10- item CATs with the full item bank indicated robust ability of the CAT approach to comprehensively characterize behavioral health function along four distinct dimensions. Conclusions Initial testing and evaluation of the SSA-BH instrument demonstrated good accuracy, reliability, and content coverage along all four scales. Behavioral function profiles of SSA claimants were generated and compared to age and sex matched norms along four scales: Mood and Emotions, Behavioral Control, Social Interactions, and Self-Efficacy. Utilizing the CAT based approach offers the ability to collect standardized, comprehensive functional information about claimants in an efficient way, which may prove useful in the context of the SSA’s work disability programs. PMID:23542404

Multidimensional student skills with collaborative filtering

NASA Astrophysics Data System (ADS)

Bergner, Yoav; Rayyan, Saif; Seaton, Daniel; Pritchard, David E.

2013-01-01

Despite the fact that a physics course typically culminates in one final grade for the student, many instructors and researchers believe that there are multiple skills that students acquire to achieve mastery. Assessment validation and data analysis in general may thus benefit from extension to multidimensional ability. This paper introduces an approach for model determination and dimensionality analysis using collaborative filtering (CF), which is related to factor analysis and item response theory (IRT). Model selection is guided by machine learning perspectives, seeking to maximize the accuracy in predicting which students will answer which items correctly. We apply the CF to response data for the Mechanics Baseline Test and combine the results with prior analysis using unidimensional IRT.

Investigation of IRT-Based Equating Methods in the Presence of Outlier Common Items

ERIC Educational Resources Information Center

Hu, Huiqin; Rogers, W. Todd; Vukmirovic, Zarko

2008-01-01

Common items with inconsistent b-parameter estimates may have a serious impact on item response theory (IRT)--based equating results. To find a better way to deal with the outlier common items with inconsistent b-parameters, the current study investigated the comparability of 10 variations of four IRT-based equating methods (i.e., concurrent…

Score Equating and Item Response Theory: Some Practical Considerations.

ERIC Educational Resources Information Center

Cook, Linda L.; Eignor, Daniel R.

The purposes of this paper are five-fold to discuss: (1) when item response theory (IRT) equating methods should provide better results than traditional methods; (2) which IRT model, the three-parameter logistic or the one-parameter logistic (Rasch), is the most reasonable to use; (3) what unique contributions IRT methods can offer the equating…

Using the Item Response Theory (IRT) for Educational Evaluation through Games

ERIC Educational Resources Information Center

Euzébio Batista, Marcelo Henrique; Victória Barbosa, Jorge Luis; da Rosa Tavares, João Elison; Hackenhaar, Jonathan Luis

2013-01-01

This article shows the application of Item Response Theory (IRT) for educational evaluation using games. The article proposes a computational model to create user profiles, called Psychometric Profile Generator (PPG). PPG uses the IRT mathematical model for exploring the levels of skills and behaviors in the form of items and/or stimuli. The model…

Technology and Teaching: Promoting Active Learning Using Individual Response Technology in Large Introductory Psychology Classes

ERIC Educational Resources Information Center

Poirier, Christopher R.; Feldman, Robert S.

2007-01-01

Individual response technology (IRT), in which students use wireless handsets to communicate real-time responses, permits the recording and display of aggregated student responses during class. In comparison to a traditional class that did not employ IRT, students using IRT performed better on exams and held positive attitudes toward the…

Using IRT Trait Estimates versus Summated Scores in Predicting Outcomes

ERIC Educational Resources Information Center

Xu, Ting; Stone, Clement A.

2012-01-01

It has been argued that item response theory trait estimates should be used in analyses rather than number right (NR) or summated scale (SS) scores. Thissen and Orlando postulated that IRT scaling tends to produce trait estimates that are linearly related to the underlying trait being measured. Therefore, IRT trait estimates can be more useful…

An Investigation of Item Fit Statistics for Mixed IRT Models

ERIC Educational Resources Information Center

Chon, Kyong Hee

2009-01-01

The purpose of this study was to investigate procedures for assessing model fit of IRT models for mixed format data. In this study, various IRT model combinations were fitted to data containing both dichotomous and polytomous item responses, and the suitability of the chosen model mixtures was evaluated based on a number of model fit procedures.…

Measurement Invariance in Careers Research: Using IRT to Study Gender Differences in Medical Students' Specialization Decisions

ERIC Educational Resources Information Center

Behrend, Tara S.; Thompson, Lori Foster; Meade, Adam W.; Newton, Dale A.; Grayson, Martha S.

2008-01-01

The current study demonstrates the use of item response theory (IRT) to conduct measurement invariance analyses in careers research. A self-report survey was used to assess the importance 1,363 fourth-year medical students placed on opportunities to provide comprehensive patient care when choosing a career specialty. IRT analyses supported…

Some Observations on the Identification and Interpretation of the 3PL IRT Model

ERIC Educational Resources Information Center

Azevedo, Caio Lucidius Naberezny

2009-01-01

The paper by Maris, G., & Bechger, T. (2009) entitled, "On the Interpreting the Model Parameters for the Three Parameter Logistic Model," addressed two important questions concerning the three parameter logistic (3PL) item response theory (IRT) model (and in a broader sense, concerning all IRT models). The first one is related to the model…

An Introduction to Item Response Theory and Rasch Models for Speech-Language Pathologists

ERIC Educational Resources Information Center

Baylor, Carolyn; Hula, William; Donovan, Neila J.; Doyle, Patrick J.; Kendall, Diane; Yorkston, Kathryn

2011-01-01

Purpose: To present a primarily conceptual introduction to item response theory (IRT) and Rasch models for speech-language pathologists (SLPs). Method: This tutorial introduces SLPs to basic concepts and terminology related to IRT as well as the most common IRT models. The article then continues with an overview of how instruments are developed…

Item response theory analysis of the life orientation test-revised: age and gender differential item functioning analyses.

PubMed

Steca, Patrizia; Monzani, Dario; Greco, Andrea; Chiesi, Francesca; Primi, Caterina

2015-06-01

This study is aimed at testing the measurement properties of the Life Orientation Test-Revised (LOT-R) for the assessment of dispositional optimism by employing item response theory (IRT) analyses. The LOT-R was administered to a large sample of 2,862 Italian adults. First, confirmatory factor analyses demonstrated the theoretical conceptualization of the construct measured by the LOT-R as a single bipolar dimension. Subsequently, IRT analyses for polytomous, ordered response category data were applied to investigate the items' properties. The equivalence of the items across gender and age was assessed by analyzing differential item functioning. Discrimination and severity parameters indicated that all items were able to distinguish people with different levels of optimism and adequately covered the spectrum of the latent trait. Additionally, the LOT-R appears to be gender invariant and, with minor exceptions, age invariant. Results provided evidence that the LOT-R is a reliable and valid measure of dispositional optimism. © The Author(s) 2014.

Stellar rotation periods determined from simultaneously measured Ca II H&K and Ca II IRT lines

NASA Astrophysics Data System (ADS)

Mittag, M.; Hempelmann, A.; Schmitt, J. H. M. M.; Fuhrmeister, B.; González-Pérez, J. N.; Schröder, K.-P.

2017-11-01

Aims: Previous studies have shown that, for late-type stars, activity indicators derived from the Ca II infrared-triplet (IRT) lines are correlated with the indicators derived from the Ca II H&K lines. Therefore, the Ca II IRT lines are in principle usable for activity studies, but they may be less sensitive when measuring the rotation period. Our goal is to determine whether the Ca II IRT lines are sufficiently sensitive to measure rotation periods and how any Ca II IRT derived rotation periods compare with periods derived from the "classical" Mount Wilson S-index. Methods: To analyse the Ca II IRT lines' sensitivity and to measure rotation periods, we define an activity index for each of the Ca II IRT lines similar to the Mount Wilson S-index and perform a period analysis for the lines separately and jointly. Results: For eleven late-type stars we can measure the rotation periods using the Ca II IRT indices similar to those found in the Mount Wilson S-index time series and find that a period derived from all four indices gives the most probable rotation period; we find good agreement for stars with already existing literature values. In a few cases the computed periodograms show a complicated structure with multiple peaks, meaning that formally different periods are derived in different indices. We show that in one case, this is due to data sampling effects and argue that denser cadence sampling is necessary to provide credible evidence for differential rotation. However, our TIGRE data for HD 101501 shows good evidence for the presence of differential rotation.

Prophylactic Effect of Probiotics on the Development of Experimental Autoimmune Myasthenia Gravis

PubMed Central

Chae, Chang-Suk; Kwon, Ho-Keun; Hwang, Ji-Sun; Kim, Jung-Eun; Im, Sin-Hyeog

2012-01-01

Probiotics are live bacteria that confer health benefits to the host physiology. Although protective role of probiotics have been reported in diverse diseases, no information is available whether probiotics can modulate neuromuscular immune disorders. We have recently demonstrated that IRT5 probiotics, a mixture of 5 probiotics, could suppress diverse experimental disorders in mice model. In this study we further investigated whether IRT5 probiotics could modulate the progression of experimental autoimmune myasthenia gravis (EAMG). Myasthenia gravis (MG) is a T cell dependent antibody mediated autoimmune disorder in which acetylcholine receptor (AChR) at the neuromuscular junction is the major auto-antigen. Oral administration of IRT5 probiotics significantly reduced clinical symptoms of EAMG such as weight loss, body trembling and grip strength. Prophylactic effect of IRT5 probiotics on EMAG is mediated by down-regulation of effector function of AChR-reactive T cells and B cells. Administration of IRT5 probiotics decreased AChR-reactive lymphocyte proliferation, anti-AChR reactive IgG levels and inflammatory cytokine levels such as IFN-γ, TNF-α, IL-6 and IL-17. Down-regulation of inflammatory mediators in AChR-reactive lymphocytes by IRT5 probiotics is mediated by the generation of regulatory dendritic cells (rDCs) that express increased levels of IL-10, TGF-β, arginase 1 and aldh1a2. Furthermore, DCs isolated from IRT5 probiotics-fed group effectively converted CD4+ T cells into CD4+Foxp3+ regulatory T cells compared with control DCs. Our data suggest that IRT5 probiotics could be applicable to modulate antibody mediated autoimmune diseases including myasthenia gravis. PMID:23284891

The probiotic mixture IRT5 ameliorates age-dependent colitis in rats.

PubMed

Jeong, Jin-Ju; Woo, Jae-Yeon; Ahn, Young-Tae; Shim, Jae-Hun; Huh, Chul-Sung; Im, Sin-Heog; Han, Myung Joo; Kim, Dong-Hyun

2015-06-01

To investigate the anti-inflammatory effect of probiotics, we orally administered IRT5 (1×10(9)CFU/rat) for 8 weeks to aged (16 months-old) Fischer 344 rats, and measured parameters of colitis. The expression levels of the inflammatory markers' inducible NO synthase (iNOS), cyclooxygenase-2 (COX2), tumor necrosis factor (TNF)-α, and interleukin (IL)-1β were higher in the colons of normal aged rats (18 months-old) than in the colons of normal young rats (6 months-old). Treatment with IRT5 suppressed the age-associated increased expression of iNOS, COX2, TNF-α, and IL-1β, and activation of NF-κB and mitogen-activated protein kinases. In a similar manner, the expression of tight junction proteins in the colon of normal aged rats was suppressed more potently than in normal young rats, and treatment of aged rats with IRT5 decreased the age-dependent suppression of tight junction proteins ZO-1, occludin, and claudin-1. Treatment with IRT5 suppressed age-associated increases in expressions of senescence markers p16 and p53 in the colon of aged rats, but increased age-suppressed expression of SIRT1. However, treatment with IRT5 inhibited age-associated increased myeloperoxidase activity in the colon. In addition, treatment with IRT5 lowered the levels of LPS in intestinal fluid and blood of aged rats, as well as the reduced concentrations of reactive oxygen species, malondialdehyde, and C-reactive protein in the blood. These findings suggest that IRT5 treatment may suppress age-dependent colitis by inhibiting gut microbiota LPS production. Copyright © 2015 Elsevier B.V. All rights reserved.

Item Response Theory as an Efficient Tool to Describe a Heterogeneous Clinical Rating Scale in De Novo Idiopathic Parkinson's Disease Patients.

PubMed

Buatois, Simon; Retout, Sylvie; Frey, Nicolas; Ueckert, Sebastian

2017-10-01

This manuscript aims to precisely describe the natural disease progression of Parkinson's disease (PD) patients and evaluate approaches to increase the drug effect detection power. An item response theory (IRT) longitudinal model was built to describe the natural disease progression of 423 de novo PD patients followed during 48 months while taking into account the heterogeneous nature of the MDS-UPDRS. Clinical trial simulations were then used to compare drug effect detection power from IRT and sum of item scores based analysis under different analysis endpoints and drug effects. The IRT longitudinal model accurately describes the evolution of patients with and without PD medications while estimating different progression rates for the subscales. When comparing analysis methods, the IRT-based one consistently provided the highest power. IRT is a powerful tool which enables to capture the heterogeneous nature of the MDS-UPDRS.

A signal detection-item response theory model for evaluating neuropsychological measures.

PubMed

Thomas, Michael L; Brown, Gregory G; Gur, Ruben C; Moore, Tyler M; Patt, Virginie M; Risbrough, Victoria B; Baker, Dewleen G

2018-02-05

Models from signal detection theory are commonly used to score neuropsychological test data, especially tests of recognition memory. Here we show that certain item response theory models can be formulated as signal detection theory models, thus linking two complementary but distinct methodologies. We then use the approach to evaluate the validity (construct representation) of commonly used research measures, demonstrate the impact of conditional error on neuropsychological outcomes, and evaluate measurement bias. Signal detection-item response theory (SD-IRT) models were fitted to recognition memory data for words, faces, and objects. The sample consisted of U.S. Infantry Marines and Navy Corpsmen participating in the Marine Resiliency Study. Data comprised item responses to the Penn Face Memory Test (PFMT; N = 1,338), Penn Word Memory Test (PWMT; N = 1,331), and Visual Object Learning Test (VOLT; N = 1,249), and self-report of past head injury with loss of consciousness. SD-IRT models adequately fitted recognition memory item data across all modalities. Error varied systematically with ability estimates, and distributions of residuals from the regression of memory discrimination onto self-report of past head injury were positively skewed towards regions of larger measurement error. Analyses of differential item functioning revealed little evidence of systematic bias by level of education. SD-IRT models benefit from the measurement rigor of item response theory-which permits the modeling of item difficulty and examinee ability-and from signal detection theory-which provides an interpretive framework encompassing the experimentally validated constructs of memory discrimination and response bias. We used this approach to validate the construct representation of commonly used research measures and to demonstrate how nonoptimized item parameters can lead to erroneous conclusions when interpreting neuropsychological test data. Future work might include the development of computerized adaptive tests and integration with mixture and random-effects models.

The IGF-1/cortisol ratio as a useful marker for monitoring training in young boxers

PubMed Central

Nassib, S; Moalla, W; Hammoudi-Nassib, S; Chtara, M; Hachana, Y; Tabka, Z; Chamari, K

2015-01-01

Training effects on plasma insulin-like growth factor-1 (IGF-1)/cortisol ratio were investigated in boxers. Thirty subjects were assigned to either the training or the control group (n = 15 in both). They were tested before the beginning of training (T0), after 5 weeks of intensive training (T1), and after 1 week of tapering (T2). Physical performances (Yo-Yo intermittent recovery test level-1), training loads, and blood sampling were obtained at T0, T1, and T2. Controls were only tested for biochemical and anthropometric parameters at T0 and T2. A significantly higher physical performance was observed at T2 compared to T1. At T1, cortisol levels were significantly increased whereas IGF-1 and insulin-like growth factor binding protein-3 (IGFBP-3) levels remained unchanged compared to baseline. At T2, cortisol levels decreased while IGF-1 and IGFBP-3 levels increased. The IGF-1/cortisol ratio decreased significantly at T1 and increased at T2, and its variations were significantly correlated with changes in training loads and Yo-Yo intermittent recovery test level 1 (IRT1) performance over the training period. Cortisol variations correlated with changes in training load (r = 0.64; p < 0.01) and Yo-Yo IRT1 performance (r = 0.78; p < 0.001) at T1 whereas IGF-1 variations correlated only with changes in Yo-Yo IRT1 performance at T2 (r = 0.71; p < 0.001). It is concluded that IGF-1/cortisol ratio could be a useful tool for monitoring training loads in young trained boxers. PMID:26985129

Detection of Differential Item Functioning with Nonlinear Regression: A Non-IRT Approach Accounting for Guessing

ERIC Educational Resources Information Center

Drabinová, Adéla; Martinková, Patrícia

2017-01-01

In this article we present a general approach not relying on item response theory models (non-IRT) to detect differential item functioning (DIF) in dichotomous items with presence of guessing. The proposed nonlinear regression (NLR) procedure for DIF detection is an extension of method based on logistic regression. As a non-IRT approach, NLR can…

Consequences of Ignoring Guessing when Estimating the Latent Density in Item Response Theory

ERIC Educational Resources Information Center

Woods, Carol M.

2008-01-01

In Ramsay-curve item response theory (RC-IRT), the latent variable distribution is estimated simultaneously with the item parameters. In extant Monte Carlo evaluations of RC-IRT, the item response function (IRF) used to fit the data is the same one used to generate the data. The present simulation study examines RC-IRT when the IRF is imperfectly…

Standard Errors and Confidence Intervals from Bootstrapping for Ramsay-Curve Item Response Theory Model Item Parameters

ERIC Educational Resources Information Center

Gu, Fei; Skorupski, William P.; Hoyle, Larry; Kingston, Neal M.

2011-01-01

Ramsay-curve item response theory (RC-IRT) is a nonparametric procedure that estimates the latent trait using splines, and no distributional assumption about the latent trait is required. For item parameters of the two-parameter logistic (2-PL), three-parameter logistic (3-PL), and polytomous IRT models, RC-IRT can provide more accurate estimates…

Validation of self-directed learning instrument and establishment of normative data for nursing students in taiwan: using polytomous item response theory.

PubMed

Cheng, Su-Fen; Lee-Hsieh, Jane; Turton, Michael A; Lin, Kuan-Chia

2014-06-01

Little research has investigated the establishment of norms for nursing students' self-directed learning (SDL) ability, recognized as an important capability for professional nurses. An item response theory (IRT) approach was used to establish norms for SDL abilities valid for the different nursing programs in Taiwan. The purposes of this study were (a) to use IRT with a graded response model to reexamine the SDL instrument, or the SDLI, originally developed by this research team using confirmatory factor analysis and (b) to establish SDL ability norms for the four different nursing education programs in Taiwan. Stratified random sampling with probability proportional to size was used. A minimum of 15% of students from the four different nursing education degree programs across Taiwan was selected. A total of 7,879 nursing students from 13 schools were recruited. The research instrument was the 20-item SDLI developed by Cheng, Kuo, Lin, and Lee-Hsieh (2010). IRT with the graded response model was used with a two-parameter logistic model (discrimination and difficulty) for the data analysis, calculated using MULTILOG. Norms were established using percentile rank. Analysis of item information and test information functions revealed that 18 items exhibited very high discrimination and two items had high discrimination. The test information function was higher in this range of scores, indicating greater precision in the estimate of nursing student SDL. Reliability fell between .80 and .94 for each domain and the SDLI as a whole. The total information function shows that the SDLI is appropriate for all nursing students, except for the top 2.5%. SDL ability norms were established for each nursing education program and for the nation as a whole. IRT is shown to be a potent and useful methodology for scale evaluation. The norms for SDL established in this research will provide practical standards for nursing educators and students in Taiwan.

An Examination of the Flynn Effect in the National Intelligence Test in Estonia

ERIC Educational Resources Information Center

Shiu, William

2012-01-01

This study examined the Flynn Effect (FE; i.e., the rise in IQ scores over time) in Estonia from Scale B of the National Intelligence Test using both classical test theory (CTT) and item response theory (IRT) methods. Secondary data from two cohorts (1934, n = 890 and 2006, n = 913) of students were analyzed, using both classical test theory (CTT)…

Effect Size Measures for Differential Item Functioning in a Multidimensional IRT Model

ERIC Educational Resources Information Center

Suh, Youngsuk

2016-01-01

This study adapted an effect size measure used for studying differential item functioning (DIF) in unidimensional tests and extended the measure to multidimensional tests. Two effect size measures were considered in a multidimensional item response theory model: signed weighted P-difference and unsigned weighted P-difference. The performance of…

A Bootstrap Generalization of Modified Parallel Analysis for IRT Dimensionality Assessment

ERIC Educational Resources Information Center

Finch, Holmes; Monahan, Patrick

2008-01-01

This article introduces a bootstrap generalization to the Modified Parallel Analysis (MPA) method of test dimensionality assessment using factor analysis. This methodology, based on the use of Marginal Maximum Likelihood nonlinear factor analysis, provides for the calculation of a test statistic based on a parametric bootstrap using the MPA…

Comment on 3PL IRT Adjustment for Guessing

ERIC Educational Resources Information Center

Chiu, Ting-Wei; Camilli, Gregory

2013-01-01

Guessing behavior is an issue discussed widely with regard to multiple choice tests. Its primary effect is on number-correct scores for examinees at lower levels of proficiency. This is a systematic error or bias, which increases observed test scores. Guessing also can inflate random error variance. Correction or adjustment for guessing formulas…

A Test of the Need Hierarchy Concept by a Markov Model of Change in Need Strength.

ERIC Educational Resources Information Center

Rauschenberger, John; And Others

1980-01-01

In this study of 547 high school graduates, Alderfer's and Maslow's need hierarchy theories were expressed in Markov chain form and were subjected to empirical test. Both models were disconfirmed. Corroborative multiwave correlational analysis also failed to support the need hierarchy concept. (Author/IRT)

Firestar-"D": Computerized Adaptive Testing Simulation Program for Dichotomous Item Response Theory Models

ERIC Educational Resources Information Center

Choi, Seung W.; Podrabsky, Tracy; McKinney, Natalie

2012-01-01

Computerized adaptive testing (CAT) enables efficient and flexible measurement of latent constructs. The majority of educational and cognitive measurement constructs are based on dichotomous item response theory (IRT) models. An integral part of developing various components of a CAT system is conducting simulations using both known and empirical…

Outlier Detection in High-Stakes Certification Testing. Research Report.

ERIC Educational Resources Information Center

Meijer, Rob R.

Recent developments of person-fit analysis in computerized adaptive testing (CAT) are discussed. Methods from statistical process control are presented that have been proposed to classify an item score pattern as fitting or misfitting the underlying item response theory (IRT) model in a CAT. Most person-fit research in CAT is restricted to…

Assessing the Accuracy and Consistency of Language Proficiency Classification under Competing Measurement Models

ERIC Educational Resources Information Center

Zhang, Bo

2010-01-01

This article investigates how measurement models and statistical procedures can be applied to estimate the accuracy of proficiency classification in language testing. The paper starts with a concise introduction of four measurement models: the classical test theory (CTT) model, the dichotomous item response theory (IRT) model, the testlet response…

KIDMAP--A Diagnostic Tool for Teachers.

ERIC Educational Resources Information Center

Lee, Yew Jin; Linacre, John M.; Yeoh, Oon Chye

While assessment is the bread and butter of the teaching profession, its practitioners usually do not extend analysis of test responses beyond simple measures such as facility or discrimination indices in classical test theory. Item response theory (IRT) has much to offer but its nonintuitive content and difficulty make it a formidable obstacle in…

Item response theory - A first approach

NASA Astrophysics Data System (ADS)

Nunes, Sandra; Oliveira, Teresa; Oliveira, Amílcar

2017-07-01

The Item Response Theory (IRT) has become one of the most popular scoring frameworks for measurement data, frequently used in computerized adaptive testing, cognitively diagnostic assessment and test equating. According to Andrade et al. (2000), IRT can be defined as a set of mathematical models (Item Response Models - IRM) constructed to represent the probability of an individual giving the right answer to an item of a particular test. The number of Item Responsible Models available to measurement analysis has increased considerably in the last fifteen years due to increasing computer power and due to a demand for accuracy and more meaningful inferences grounded in complex data. The developments in modeling with Item Response Theory were related with developments in estimation theory, most remarkably Bayesian estimation with Markov chain Monte Carlo algorithms (Patz & Junker, 1999). The popularity of Item Response Theory has also implied numerous overviews in books and journals, and many connections between IRT and other statistical estimation procedures, such as factor analysis and structural equation modeling, have been made repeatedly (Van der Lindem & Hambleton, 1997). As stated before the Item Response Theory covers a variety of measurement models, ranging from basic one-dimensional models for dichotomously and polytomously scored items and their multidimensional analogues to models that incorporate information about cognitive sub-processes which influence the overall item response process. The aim of this work is to introduce the main concepts associated with one-dimensional models of Item Response Theory, to specify the logistic models with one, two and three parameters, to discuss some properties of these models and to present the main estimation procedures.

Item response theory, computerized adaptive testing, and PROMIS: assessment of physical function.

PubMed

Fries, James F; Witter, James; Rose, Matthias; Cella, David; Khanna, Dinesh; Morgan-DeWitt, Esi

2014-01-01

Patient-reported outcome (PRO) questionnaires record health information directly from research participants because observers may not accurately represent the patient perspective. Patient-reported Outcomes Measurement Information System (PROMIS) is a US National Institutes of Health cooperative group charged with bringing PRO to a new level of precision and standardization across diseases by item development and use of item response theory (IRT). With IRT methods, improved items are calibrated on an underlying concept to form an item bank for a "domain" such as physical function (PF). The most informative items can be combined to construct efficient "instruments" such as 10-item or 20-item PF static forms. Each item is calibrated on the basis of the probability that a given person will respond at a given level, and the ability of the item to discriminate people from one another. Tailored forms may cover any desired level of the domain being measured. Computerized adaptive testing (CAT) selects the best items to sharpen the estimate of a person's functional ability, based on prior responses to earlier questions. PROMIS item banks have been improved with experience from several thousand items, and are calibrated on over 21,000 respondents. In areas tested to date, PROMIS PF instruments are superior or equal to Health Assessment Questionnaire and Medical Outcome Study Short Form-36 Survey legacy instruments in clarity, translatability, patient importance, reliability, and sensitivity to change. Precise measures, such as PROMIS, efficiently incorporate patient self-report of health into research, potentially reducing research cost by lowering sample size requirements. The advent of routine IRT applications has the potential to transform PRO measurement.

Time change of perceptual reversal of ambiguous figures by rTMS.

PubMed

Nojima, K; Ge, S; Katayama, Y; Iramina, K

2010-01-01

The aim of this study was to investigate the effect of stimulus frequency and number of pulses during rTMS (repetitive transcranial magnetic stimulation) on the phenomenon of perceptual reversal. Particularly, we focused on the temporal dynamics of perceptual reversal in the right SPL (superior parietal lobule), using the spinning wheel illusion. We measured the IRT (inter-reversal time) of perceptual reversal. To investigate whether stimulus frequency or the number of pulses is critical for the rTMS effect, we applied the following schedules over the right SPL and the right PTL (posterior temporal lobe): 0.25Hz 60 pulses, 0.25Hz 120pulses, 0.5Hz 120 pulses, and 1Hz 120 pulses biphasic rTMS at 90% of the resting motor threshold. As a control, we included a No-TMS condition. The results showed that rTMS with 0.25Hz 60 pulses over the right SPL caused shorter IRT. There were no significant differences between IRTs for rTMS with 0.25Hz 120 pulses, 0.5Hz 120 pulses or 1Hz 120 pulses over the right SPL. Comparing these results with those of a previous study, we found that an rTMS condition with 60 pulses causes shorter IRT; 240 pulses causes longer IRT; and 120 pulses does not change IRT. Therefore, when applying rTMS over the right SPL, the IRT of perceptual reversal is primarily affected by the number of pulses.

Applying Multidimensional Item Response Theory Models in Validating Test Dimensionality: An Example of K-12 Large-Scale Science Assessment

ERIC Educational Resources Information Center

Li, Ying; Jiao, Hong; Lissitz, Robert W.

2012-01-01

This study investigated the application of multidimensional item response theory (IRT) models to validate test structure and dimensionality. Multiple content areas or domains within a single subject often exist in large-scale achievement tests. Such areas or domains may cause multidimensionality or local item dependence, which both violate the…

Examining Differential Item Functions of Different Item Ordered Test Forms According to Item Difficulty Levels

ERIC Educational Resources Information Center

Çokluk, Ömay; Gül, Emrah; Dogan-Gül, Çilem

2016-01-01

The study aims to examine whether differential item function is displayed in three different test forms that have item orders of random and sequential versions (easy-to-hard and hard-to-easy), based on Classical Test Theory (CTT) and Item Response Theory (IRT) methods and bearing item difficulty levels in mind. In the correlational research, the…

Immunity Under 42 U.S.C Section 1983: A Benefit to the Public? "Sparks v. Duval County Ranch Co."

ERIC Educational Resources Information Center

D'Angelo, Robert J., Jr.

1979-01-01

With its holding that both judge Carrillo and Clinton Manges were immune, one by judicial immunity, the other by "vicarious" immunity, the court condoned both judicial and private corruption. Available from University of Connecticut School of Law, 1800 Asylum Avenue, West Hartford, CT 06117. (Author/IRT)

Modern Airfoil Ice Accretions

NASA Technical Reports Server (NTRS)

Addy, Harold E., Jr.; Potapczuk, Mark G.; Sheldon, David W.

1997-01-01

This report presents results from the first icing tests performed in the Modem Airfoils program. Two airfoils have been subjected to icing tests in the NASA Lewis Icing Research Tunnel (IRT). Both airfoils were two dimensional airfoils; one was representative of a commercial transport airfoil while the other was representative of a business jet airfoil. The icing test conditions were selected from the FAR Appendix C envelopes. Effects on aerodynamic performance are presented including the effects of varying amounts of glaze ice as well as the effects of approximately the same amounts of glaze, mixed, and rime ice. Actual ice shapes obtained in these tests are also presented for these cases. In addition, comparisons are shown between ice shapes from the tests and ice shapes predicted by the computer code, LEWICE for similar conditions. Significant results from the tests are that relatively small amounts of ice can have nearly as much effect on airfoil lift coefficient as much greater amounts of ice and that glaze ice usually has a more detrimental effect than either rime or mixed ice. LEWICE predictions of ice shapes, in general, compared reasonably well with ice shapes obtained in the IRT, although differences in details of the ice shapes were observed.

Fitting IRT Models to Dichotomous and Polytomous Data: Assessing the Relative Model-Data Fit of Ideal Point and Dominance Models

ERIC Educational Resources Information Center

Tay, Louis; Ali, Usama S.; Drasgow, Fritz; Williams, Bruce

2011-01-01

This study investigated the relative model-data fit of an ideal point item response theory (IRT) model (the generalized graded unfolding model [GGUM]) and dominance IRT models (e.g., the two-parameter logistic model [2PLM] and Samejima's graded response model [GRM]) to simulated dichotomous and polytomous data generated from each of these models.…

Performance of the Generalized S-X[Superscript 2] Item Fit Index for Polytomous IRT Models

ERIC Educational Resources Information Center

Kang, Taehoon; Chen, Troy T.

2008-01-01

Orlando and Thissen's S-X[superscript 2] item fit index has performed better than traditional item fit statistics such as Yen' s Q[subscript 1] and McKinley and Mill' s G[superscript 2] for dichotomous item response theory (IRT) models. This study extends the utility of S-X[superscript 2] to polytomous IRT models, including the generalized partial…

Geometrical Characteristics of Cd-Rich Inclusion Defects in CdZnTe Materials

NASA Astrophysics Data System (ADS)

Xu, Chao; Sheng, Fengfeng; Yang, Jianrong

2017-08-01

The geometrical characteristics of Cd-rich inclusion defects in CdZnTe crystals have been investigated by infrared transmission (IRT) microscopy and chemical etching methods, revealing that they are composed of a Cd-rich inclusion core zone with high dislocation density and defect extension belts. Based on the experimental results, the orientation and shape of these belts were determined, showing that their extension directions in three-dimensional (3-D) space are along <211> crystal orientation. To explain the observed IRT images of Cd-rich inclusion defects, a 3-D model with plate-shaped structure for dislocation extension belts is proposed. Greyscale IRT images of dislocation extension belts thus depend on their absorption layer thickness. Assuming that defects can be discerned by IRT microscopy only when their absorption layer thickness is greater than twice that of the plate-shaped dislocation extension belts, this 3-D defect model can rationalize the IRT images of Cd-rich inclusion defects.

Psychometric Properties of IRT Proficiency Estimates

ERIC Educational Resources Information Center

Kolen, Michael J.; Tong, Ye

2010-01-01

Psychometric properties of item response theory proficiency estimates are considered in this paper. Proficiency estimators based on summed scores and pattern scores include non-Bayes maximum likelihood and test characteristic curve estimators and Bayesian estimators. The psychometric properties investigated include reliability, conditional…

A Structural View of American Educational History

ERIC Educational Resources Information Center

Maxcy, Spencer J.

1977-01-01

Displays the components of the structuralist views of Levi-Strauss, Michel Foucault, and Thomas S. Kuhn; constructs a model for doing structuralist studies in educational research; and tests the model on the pragmatic/progressive period in American educational history. (Author/IRT)

A new network of faint calibration stars from the near infrared spectrometer (NIRS) on the IRTS

NASA Technical Reports Server (NTRS)

Freund, Minoru M.; Matsuura, Mikako; Murakami, Hiroshi; Cohen, Martin; Noda, Manabu; Matsuura, Shuji; Matsumoto, Toshio

1997-01-01

The point source extraction and calibration of the near infrared spectrometer (NIRS) onboard the Infrared Telescope in Space (IRTS) is described. About 7 percent of the sky was observed during a one month mission in the range of 1.4 micrometers to 4 micrometers. The accuracy of the spectral shape and absolute values of calibration stars provided by the NIRS/IRTS were validated.

Inoculation with Bacillus subtilis and Azospirillum brasilense produces abscisic acid that reduces IRT1-mediated cadmium uptake of roots.

PubMed

Xu, Qianru; Pan, Wei; Zhang, Ranran; Lu, Qi; Xue, Wanlei; Wu, Cainan; Song, Bixiu; Du, Shaoting

2018-05-08

Cadmium (Cd) contamination of agricultural soils represents a serious risk to crop safety. A new strategy using abscisic acid (ABA)-generating bacteria, Bacillus subtilis or Azospirillum brasilense, was developed to reduce the Cd accumulation in plants grown in Cd-contaminated soil. Inoculation with either bacterium resulted in a pronounced increase in the ABA level in wild-type Arabidopsis Col-0 plants, accompanied by a decrease in Cd levels in plant tissues, which mitigated the Cd toxicity. As a consequence, the growth of plants exposed to Cd was improved. Nevertheless, B. subtilis and A. brasilense inoculation had little effect on Cd levels and toxicity in the ABA-insensitive mutant snrk 2.2/2.3, indicating that the action of ABA is required for these bacteria to reduce Cd accumulation in plants. Furthermore, inoculation with either B. subtilis or A. brasilense down-regulated the expression of IRT1 (IRON-REGULATED TRANSPORTER 1) in the roots of wild-type plants and had little effect on Cd levels in the IRT1-knockout mutants irt1-1 and irt1-2. In summary, we conclude that B. subtilis and A. brasilense can reduce Cd levels in plants via an IRT1-dependent ABA-mediated mechanism.

Medical applications of infrared thermography: A review

NASA Astrophysics Data System (ADS)

Lahiri, B. B.; Bagavathiappan, S.; Jayakumar, T.; Philip, John

2012-07-01

Abnormal body temperature is a natural indicator of illness. Infrared thermography (IRT) is a fast, passive, non-contact and non-invasive alternative to conventional clinical thermometers for monitoring body temperature. Besides, IRT can also map body surface temperature remotely. Last five decades witnessed a steady increase in the utility of thermal imaging cameras to obtain correlations between the thermal physiology and skin temperature. IRT has been successfully used in diagnosis of breast cancer, diabetes neuropathy and peripheral vascular disorders. It has also been used to detect problems associated with gynecology, kidney transplantation, dermatology, heart, neonatal physiology, fever screening and brain imaging. With the advent of modern infrared cameras, data acquisition and processing techniques, it is now possible to have real time high resolution thermographic images, which is likely to surge further research in this field. The present efforts are focused on automatic analysis of temperature distribution of regions of interest and their statistical analysis for detection of abnormalities. This critical review focuses on advances in the area of medical IRT. The basics of IRT, essential theoretical background, the procedures adopted for various measurements and applications of IRT in various medical fields are discussed in this review. Besides background information is provided for beginners for better understanding of the subject.

Efficacy of a cognitive-behavioral treatment for insomnia and nightmares in Afghanistan and Iraq veterans with PTSD.

PubMed

Margolies, Skye Ochsner; Rybarczyk, Bruce; Vrana, Scott R; Leszczyszyn, David J; Lynch, John

2013-10-01

Sleep disturbances are a core and salient feature of posttraumatic stress disorder (PTSD). Pilot studies have indicated that combined cognitive-behavioral therapy for insomnia (CBT-I) and imagery rehearsal therapy (IRT) for nightmares improves sleep as well as PTSD symptoms. The present study randomized 40 combat veterans (mean age 37.7 years; 90% male and 60% African American) who served in Afghanistan and/or Iraq (Operation Enduring Freedom [OEF]/Operation Iraqi Freedom [OIF]) to 4 sessions of CBT-I with adjunctive IRT or a waitlist control group. Two thirds of participants had nightmares at least once per week and received the optional IRT module. At posttreatment, veterans who participated in CBT-I/IRT reported improved subjectively and objectively measured sleep, a reduction in PTSD symptom severity and PTSD-related nighttime symptoms, and a reduction in depression and distressed mood compared to the waitlist control group. The findings from this first controlled study with OEF/OIF veterans suggest that CBT-I combined with adjunctive IRT may hold promise for reducing both insomnia and PTSD symptoms. Given the fact that only half of the patients with nightmares fully implemented the brief IRT protocol, future studies should determine if this supplement adds differential efficacy to CBT-I alone. © 2013 Wiley Periodicals, Inc.

Item response theory analyses of the Delis-Kaplan Executive Function System card sorting subtest.

PubMed

Spencer, Mercedes; Cho, Sun-Joo; Cutting, Laurie E

2018-02-02

In the current study, we examined the dimensionality of the 16-item Card Sorting subtest of the Delis-Kaplan Executive Functioning System assessment in a sample of 264 native English-speaking children between the ages of 9 and 15 years. We also tested for measurement invariance for these items across age and gender groups using item response theory (IRT). Results of the exploratory factor analysis indicated that a two-factor model that distinguished between verbal and perceptual items provided the best fit to the data. Although the items demonstrated measurement invariance across age groups, measurement invariance was violated for gender groups, with two items demonstrating differential item functioning for males and females. Multigroup analysis using all 16 items indicated that the items were more effective for individuals whose IRT scale scores were relatively high. A single-group explanatory IRT model using 14 non-differential item functioning items showed that for perceptual ability, females scored higher than males and that scores increased with age for both males and females; for verbal ability, the observed increase in scores across age differed for males and females. The implications of these findings are discussed.

Splicing factor SR34b mutation reduces cadmium tolerance in Arabidopsis by regulating iron-regulated transporter 1 gene

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

Zhang, Wentao; Du, Bojing; Liu, Di

Highlights: • Arabidopsis splicing factor SR34b gene is cadmium-inducible. • SR34b T-DNA insertion mutant is sensitive to cadmium due to high cadmium uptake. • SR34b is a regulator of cadmium transporter IRT1 at the posttranscription level. • These results highlight the roles of splicing factors in cadmium tolerance of plant. - Abstract: Serine/arginine-rich (SR) proteins are important splicing factors. However, the biological functions of plant SR proteins remain unclear especially in abiotic stresses. Cadmium (Cd) is a non-essential element that negatively affects plant growth and development. In this study, we provided clear evidence for SR gene involved in Cd tolerancemore » in planta. Systemic expression analysis of 17 Arabidopsis SR genes revealed that SR34b is the only SR gene upregulated by Cd, suggesting its potential roles in Arabidopsis Cd tolerance. Consistent with this, a SR34b T-DNA insertion mutant (sr34b) was moderately sensitive to Cd, which had higher Cd{sup 2+} uptake rate and accumulated Cd in greater amounts than wild-type. This was due to the altered expression of iron-regulated transporter 1 (IRT1) gene in sr34b mutant. Under normal growth conditions, IRT1 mRNAs highly accumulated in sr34b mutant, which was a result of increased stability of IRT1 mRNA. Under Cd stress, however, sr34b mutant plants had a splicing defect in IRT1 gene, thus reducing the IRT1 mRNA accumulation. Despite of this, sr34b mutant plants still constitutively expressed IRT1 proteins under Cd stress, thereby resulting in Cd stress-sensitive phenotype. We therefore propose the essential roles of SR34b in posttranscriptional regulation of IRT1 expression and identify it as a regulator of Arabidopsis Cd tolerance.« less

ZIP14 and DMT1 in the liver, pancreas, and heart are differentially regulated by iron deficiency and overload: implications for tissue iron uptake in iron-related disorders

PubMed Central

Nam, Hyeyoung; Wang, Chia-Yu; Zhang, Lin; Zhang, Wei; Hojyo, Shintaro; Fukada, Toshiyuki; Knutson, Mitchell D.

2013-01-01

The liver, pancreas, and heart are particularly susceptible to iron-related disorders. These tissues take up plasma iron from transferrin or non-transferrin-bound iron, which appears during iron overload. Here, we assessed the effect of iron status on the levels of the transmembrane transporters, ZRT/IRT-like protein 14 and divalent metal-ion transporter-1, which have both been implicated in transferrin- and non-transferrin-bound iron uptake. Weanling male rats (n=6/group) were fed an iron-deficient, iron-adequate, or iron-overloaded diet for 3 weeks. ZRT/IRT-like protein 14, divalent metal-ion transporter-1 protein and mRNA levels in liver, pancreas, and heart were determined by using immunoblotting and quantitative reverse transcriptase polymerase chain reaction analysis. Confocal immunofluorescence microscopy was used to localize ZRT/IRT-like protein 14 in the liver and pancreas. ZRT/IRT-like protein 14 and divalent metal-ion transporter-1 protein levels were also determined in hypotransferrinemic mice with genetic iron overload. Hepatic ZRT/IRT-like protein 14 levels were found to be 100% higher in iron-loaded rats than in iron-adequate controls. By contrast, hepatic divalent metal-ion transporter-1 protein levels were 70% lower in iron-overloaded animals and nearly 3-fold higher in iron-deficient ones. In the pancreas, ZRT/IRT-like protein 14 levels were 50% higher in iron-overloaded rats, and in the heart, divalent metal-ion transporter-1 protein levels were 4-fold higher in iron-deficient animals. At the mRNA level, ZRT/IRT-like protein 14 expression did not vary with iron status, whereas divalent metal-ion transporter-1 expression was found to be elevated in iron-deficient livers. Immunofluorescence staining localized ZRT/IRT-like protein 14 to the basolateral membrane of hepatocytes and to acinar cells of the pancreas. Hepatic ZRT/IRT-like protein 14, but not divalent metal-ion transporter-1, protein levels were elevated in iron-loaded hypotransferrinemic mice. In conclusion, ZRT/IRT-like protein 14 protein levels are up-regulated in iron-loaded rat liver and pancreas and in hypotransferrinemic mouse liver. Divalent metal-ion transporter-1 protein levels are down-regulated in iron-loaded rat liver, and up-regulated in iron-deficient liver and heart. Our results provide insight into the potential contributions of these transporters to tissue iron uptake during iron deficiency and overload. PMID:23349308

A Multidimensional Partial Credit Model with Associated Item and Test Statistics: An Application to Mixed-Format Tests

ERIC Educational Resources Information Center

Yao, Lihua; Schwarz, Richard D.

2006-01-01

Multidimensional item response theory (IRT) models have been proposed for better understanding the dimensional structure of data or to define diagnostic profiles of student learning. A compensatory multidimensional two-parameter partial credit model (M-2PPC) for constructed-response items is presented that is a generalization of those proposed to…

A Simple Answer to a Simple Question on Changing Answers

ERIC Educational Resources Information Center

Bridgeman, Brent

2012-01-01

In an article in the Winter 2011 issue of the "Journal of Educational Measurement", van der Linden, Jeon, and Ferrara suggested that "test takers should trust their initial instincts and retain their initial responses when they have the opportunity to review test items." They presented a complex IRT model that appeared to show that students would…

Certifying Functional Literacy: Competency Testing and Implications for Due Process and Equal Educational Opportunity.

ERIC Educational Resources Information Center

Lewis, Donald Marion

1979-01-01

Demonstrates the role the guarantee of due process can play in ensuring that vital interests in public education not be lost through erroneous assessments of a student's proficiency in basic skills, and describes the limits constitutional and statutory guarantees of equal educational opportunity place on the use of competency testing. (Author/IRT)

The Role of Psychometric Modeling in Test Validation: An Application of Multidimensional Item Response Theory

ERIC Educational Resources Information Center

Schilling, Stephen G.

2007-01-01

In this paper the author examines the role of item response theory (IRT), particularly multidimensional item response theory (MIRT) in test validation from a validity argument perspective. The author provides justification for several structural assumptions and interpretations, taking care to describe the role he believes they should play in any…

The Effect of Differential Motivation on IRT Linking

ERIC Educational Resources Information Center

Mittelhaëuser, Marie-Anne; Béguin, Anton A.; Sijtsma, Klaas

2015-01-01

The purpose of this study was to investigate whether simulated differential motivation between the stakes for operational tests and anchor items produces an invalid linking result if the Rasch model is used to link the operational tests. This was done for an external anchor design and a variation of a pretest design. The study also investigated…

Modeling Nonignorable Missing Data in Speeded Tests

ERIC Educational Resources Information Center

Glas, Cees A. W.; Pimentel, Jonald L.

2008-01-01

In tests with time limits, items at the end are often not reached. Usually, the pattern of missing responses depends on the ability level of the respondents; therefore, missing data are not ignorable in statistical inference. This study models data using a combination of two item response theory (IRT) models: one for the observed response data and…

Asymptotic Standard Errors of Observed-Score Equating with Polytomous IRT Models

ERIC Educational Resources Information Center

Andersson, Björn

2016-01-01

In observed-score equipercentile equating, the goal is to make scores on two scales or tests measuring the same construct comparable by matching the percentiles of the respective score distributions. If the tests consist of different items with multiple categories for each item, a suitable model for the responses is a polytomous item response…

A Note on the Reliability Coefficients for Item Response Model-Based Ability Estimates

ERIC Educational Resources Information Center

Kim, Seonghoon

2012-01-01

Assuming item parameters on a test are known constants, the reliability coefficient for item response theory (IRT) ability estimates is defined for a population of examinees in two different ways: as (a) the product-moment correlation between ability estimates on two parallel forms of a test and (b) the squared correlation between the true…

Linking Outcomes from Peabody Picture Vocabulary Test Forms Using Item Response Models

ERIC Educational Resources Information Center

Hoffman, Lesa; Templin, Jonathan; Rice, Mabel L.

2012-01-01

Purpose: The present work describes how vocabulary ability as assessed by 3 different forms of the Peabody Picture Vocabulary Test (PPVT; Dunn & Dunn, 1997) can be placed on a common latent metric through item response theory (IRT) modeling, by which valid comparisons of ability between samples or over time can then be made. Method: Responses…

Freedom from Establishment and Unneutrality in Public School Instruction and Religious School Regulation.

ERIC Educational Resources Information Center

Bird, Wendell R.

1979-01-01

Argues for a substantial neutrality test to replace the absolute separation form of the tripartite test in construing and applying the establishment clause of the First Amendment. Available from Harvard Society for Law and Public Policy, Inc., Langdell Hall, Harvard Law School, Cambridge, MA 02138; $4.00 per issue. (Author/IRT)

Perfluorochemical (PFC) exposure in children: associations with impaired response inhibition.

PubMed

Gump, Brooks B; Wu, Qian; Dumas, Amy K; Kannan, Kurunthachalam

2011-10-01

Perfluorinated chemicals (PFCs) have been used widely in consumer products since the 1950s and are currently found at detectable levels in the blood of humans and animals across the globe. In stark contrast to this widespread exposure to PFCs, there is relatively little research on potential adverse health effects of exposure to these chemicals. We performed this cross-sectional study to determine if specific blood PFC levels are associated with impaired response inhibition in children. Blood levels of 11 PFCs were measured in children (N = 83) and 6 PFCs: perfluorooctane sulfonate (PFOS), perfluorohexane sulfate (PFHxS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorooctanesulfonamide (PFOSA), and perfluorodecanoic acid (PFDA) - were found at detectable levels in most children (87.5% or greater had detectable levels). These levels were analyzed in relation to the differential reinforcement of low rates of responding (DRL) task. This task rewards delays between responses (i.e., longer inter-response times; IRTs) and therefore constitutes a measure of response inhibition. Higher levels of blood PFOS, PFNA, PFDA, PFHxS, and PFOSA were associated with significantly shorter IRTs during the DRL task. The magnitude of these associations was such that IRTs during the task decreased by 29-34% for every 1 SD increase in the corresponding blood PFC. This study suggests an association between PFC exposure and children's impulsivity. Although intriguing, there is a need for further investigation and replication with a larger sample of children.

RhinAsthma patient perspective: A Rasch validation study.

PubMed

Molinengo, Giorgia; Baiardini, Ilaria; Braido, Fulvio; Loera, Barbara

2018-02-01

In daily practice, Health-Related Quality of Life (HRQoL) tools are useful for supplementing clinical data with the patient's perspective. To encourage their use by clinicians, the availability of tools that can quickly provide valid results is crucial. A new HRQoL tool has been proposed for patients with asthma and rhinitis: the RhinAsthma Patient Perspective-RAPP. The aim of this study was to evaluate the psychometric robustness of the RAPP using the Item Response Theory (IRT) approach, to evaluate the scalability of items and test whether or not patients use the items response scale correctly. 155 patients (53.5% women, mean age 39.1, range 16-76) were recruited during a multicenter study. RAPP metric properties were investigated using IRT models. Differential item functioning (DIF) was used for gender, age, and asthma control test (ACT). The RAPP adequately fitted the Rating Scale model, demonstrating the equality of the rating scale structure for all items. All statistics on items were satisfactory. The RAPP had adequate internal reliability and showed good ability to discriminate among different groups of participants. DIF analysis indicated that there were no differential item functioning issues for gender. One item showed a DIF by age and four items by ACT. The psychometric evaluation performed using IRT models demonstrated that the RAPP met all the criteria to be considered a reliable and valid method of measurement. From a clinical perspective, this will allow physicians to confidently interpret scores as good indicators of Quality of Life of patients with asthma.

Validating a multiple mini-interview question bank assessing entry-level reasoning skills in candidates for graduate-entry medicine and dentistry programmes.

PubMed

Roberts, Chris; Zoanetti, Nathan; Rothnie, Imogene

2009-04-01

The multiple mini-interview (MMI) was initially designed to test non-cognitive characteristics related to professionalism in entry-level students. However, it may be testing cognitive reasoning skills. Candidates to medical and dental schools come from diverse backgrounds and it is important for the validity and fairness of the MMI that these background factors do not impact on their scores. A suite of advanced psychometric techniques drawn from item response theory (IRT) was used to validate an MMI question bank in order to establish the conceptual equivalence of the questions. Bias against candidate subgroups of equal ability was investigated using differential item functioning (DIF) analysis. All 39 questions had a good fit to the IRT model. Of the 195 checklist items, none were found to have significant DIF after visual inspection of expected score curves, consideration of the number of applicants per category, and evaluation of the magnitude of the DIF parameter estimates. The question bank contains items that have been studied carefully in terms of model fit and DIF. Questions appear to measure a cognitive unidimensional construct, 'entry-level reasoning skills in professionalism', as suggested by goodness-of-fit statistics. The lack of items exhibiting DIF is encouraging in a contemporary high-stakes admission setting where candidates of diverse personal, cultural and academic backgrounds are assessed by common means. This IRT approach has potential to provide assessment designers with a quality control procedure that extends to the level of checklist items.

Analysis of the psychometric properties of the Multiple Sclerosis Impact Scale-29 (MSIS-29) in relapsing–remitting multiple sclerosis using classical and modern test theory

PubMed Central

Wyrwich, KW; Phillips, GA; Vollmer, T; Guo, S

2016-01-01

Background Investigations using classical test theory support the psychometric properties of the original version of the Multiple Sclerosis Impact Scale (MSIS-29v1), a disease-specific measure of multiple sclerosis (MS) impact (physical and psychological subscales). Later, assessments of the MSIS-29v1 in an MS community-based sample using Rasch analysis led to revisions of the instrument’s response options (MSIS-29v2). Objective The objective of this paper is to evaluate the psychometric properties of the MSIS-29v1 in a clinical trial cohort of relapsing–remitting MS patients (RRMS). Methods Data from 600 patients with RRMS enrolled in the SELECT clinical trial were used. Assessments were performed at baseline and at Weeks 12, 24, and 52. In addition to traditional psychometric analyses, Item Response Theory (IRT) and Rasch analysis were used to evaluate the measurement properties of the MSIS-29v1. Results Both MSIS-29v1 subscales demonstrated strong reliability, construct validity, and responsiveness. The IRT and Rasch analysis showed overall support for response category threshold ordering, person-item fit, and item fit for both subscales. Conclusions Both MSIS-29v1 subscales demonstrated robust measurement properties using classical, IRT, and Rasch techniques. Unlike previous research using a community-based sample, the MSIS-29v1 was found to be psychometrically sound to assess physical and psychological impairments in a clinical trial sample of patients with RRMS. PMID:28607741

Analysis of the psychometric properties of the Multiple Sclerosis Impact Scale-29 (MSIS-29) in relapsing-remitting multiple sclerosis using classical and modern test theory.

PubMed

Bacci, E D; Wyrwich, K W; Phillips, G A; Vollmer, T; Guo, S

2016-01-01

Investigations using classical test theory support the psychometric properties of the original version of the Multiple Sclerosis Impact Scale (MSIS-29v1), a disease-specific measure of multiple sclerosis (MS) impact (physical and psychological subscales). Later, assessments of the MSIS-29v1 in an MS community-based sample using Rasch analysis led to revisions of the instrument's response options (MSIS-29v2). The objective of this paper is to evaluate the psychometric properties of the MSIS-29v1 in a clinical trial cohort of relapsing-remitting MS patients (RRMS). Data from 600 patients with RRMS enrolled in the SELECT clinical trial were used. Assessments were performed at baseline and at Weeks 12, 24, and 52. In addition to traditional psychometric analyses, Item Response Theory (IRT) and Rasch analysis were used to evaluate the measurement properties of the MSIS-29v1. Both MSIS-29v1 subscales demonstrated strong reliability, construct validity, and responsiveness. The IRT and Rasch analysis showed overall support for response category threshold ordering, person-item fit, and item fit for both subscales. Both MSIS-29v1 subscales demonstrated robust measurement properties using classical, IRT, and Rasch techniques. Unlike previous research using a community-based sample, the MSIS-29v1 was found to be psychometrically sound to assess physical and psychological impairments in a clinical trial sample of patients with RRMS.

First Evaluation of Infrared Thermography as a Tool for the Monitoring of Udder Health Status in Farms of Dairy Cows.

PubMed

Zaninelli, Mauro; Redaelli, Veronica; Luzi, Fabio; Bronzo, Valerio; Mitchell, Malcolm; Dell'Orto, Vittorio; Bontempo, Valentino; Cattaneo, Donata; Savoini, Giovanni

2018-03-14

The aim of the present study was to test infrared thermography (IRT), under field conditions, as a possible tool for the evaluation of cow udder health status. Thermographic images (n. 310) from different farms (n. 3) were collected and evaluated using a dedicated software application to calculate automatically and in a standardized way, thermographic indices of each udder. Results obtained have confirmed a significant relationship between udder surface skin temperature (USST) and classes of somatic cell count in collected milk samples. Sensitivity and specificity in the classification of udder health were: 78.6% and 77.9%, respectively, considering a level of somatic cell count ( SCC ) of 200,000 cells/mL as a threshold to classify a subclinical mastitis or 71.4% and 71.6%, respectively when a threshold of 400,000 cells/mL was adopted. Even though the sensitivity and specificity were lower than in other published papers dealing with non-automated analysis of IRT images, they were considered acceptable as a first field application of this new and developing technology. Future research will permit further improvements in the use of IRT, at farm level. Such improvements could be attained through further image processing and enhancement, and the application of indicators developed and tested in the present study with the purpose of developing a monitoring system for the automatic and early detection of mastitis in individual animals on commercial farms.

First Evaluation of Infrared Thermography as a Tool for the Monitoring of Udder Health Status in Farms of Dairy Cows

PubMed Central

Luzi, Fabio; Bronzo, Valerio; Mitchell, Malcolm; Dell’Orto, Vittorio; Bontempo, Valentino; Savoini, Giovanni

2018-01-01

The aim of the present study was to test infrared thermography (IRT), under field conditions, as a possible tool for the evaluation of cow udder health status. Thermographic images (n. 310) from different farms (n. 3) were collected and evaluated using a dedicated software application to calculate automatically and in a standardized way, thermographic indices of each udder. Results obtained have confirmed a significant relationship between udder surface skin temperature (USST) and classes of somatic cell count in collected milk samples. Sensitivity and specificity in the classification of udder health were: 78.6% and 77.9%, respectively, considering a level of somatic cell count (SCC) of 200,000 cells/mL as a threshold to classify a subclinical mastitis or 71.4% and 71.6%, respectively when a threshold of 400,000 cells/mL was adopted. Even though the sensitivity and specificity were lower than in other published papers dealing with non-automated analysis of IRT images, they were considered acceptable as a first field application of this new and developing technology. Future research will permit further improvements in the use of IRT, at farm level. Such improvements could be attained through further image processing and enhancement, and the application of indicators developed and tested in the present study with the purpose of developing a monitoring system for the automatic and early detection of mastitis in individual animals on commercial farms. PMID:29538352

Assessing the improvements in the newborn screening strategy for cystic fibrosis in the Balearic Islands.

PubMed

Bauça, Josep Miquel; Morell-Garcia, Daniel; Vila, Magdalena; Pérez, Gerardo; Heine-Suñer, Damián; Figuerola, Joan

2015-04-01

Newborn screening strategies for cystic fibrosis (CF) are run worldwide, and aim at the early detection of the disorder to significantly improve the quality of life. Elevated levels of immunoreactive trypsinogen (IRT) represent a high likelihood for the screened child to be affected with CF. However, the specificity of IRT is low. The objective of this study was to assess the screening program in the Balearic Islands during the past 14 years. We evaluated all results of the screening program after 14 years, by considering all changes in the protocol and assessing the number of positive samples, the mutations detected, the number of sweat tests performed, the incidence of CF and the presence of false-negative cases. Despite a great variability among the different Balearic Islands, the global incidence of CF was 1:6059 for the 14 years assessed. The incidence in the smaller islands is about 5 times higher than in Majorca (1:2376 versus 1:10,613). After different changes in the protocol, an IRT cut-off value of 60 ng/mL was established. The two most common mutations are ΔF508 and G542X, in accordance with other geographical regions. The changes in the protocol helped reduce the number of sweat tests performed without any increase in the false-negative rate. Copyright © 2015 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Using the Self-Directed Search in Research: Selecting a Representative Pool of Items to Measure Vocational Interests

ERIC Educational Resources Information Center

Poitras, Sarah-Caroline; Guay, Frederic; Ratelle, Catherine F.

2012-01-01

Using Item Response Theory (IRT) and Confirmatory Factor Analysis (CFA), the goal of this study was to select a reduced pool of items from the French Canadian version of the Self-Directed Search--Activities Section (Holland, Fritzsche, & Powell, 1994). Two studies were conducted. Results of Study 1, involving 727 French Canadian students,…

Diagnostic problems in cystic fibrosis - specific characteristics of a group of infants and young children diagnosed positive through neonatal screening, in whom cystic fibrosis had not been diagnosed.

PubMed

Woś, Halina; Sankiewicz-Szkółka, Magda; Więcek, Sabina; Kordys-Darmolińska, Bożena; Grzybowska-Chlebowczyk, Urszula; Kniażewska, Maria

2015-01-01

Neonatal cystic fibrosis screening contributes to an early diagnosis of cystic fibrosis and to implementing appropriate therapeutic management. Long-standing screening tests have made it possible to identify a group of newborns in whom the diagnosis was ambiguous and required further specialised tests. The aim is to present cases of patients with a positive result of newborn screening for cystic fibrosis who were found to be carriers of the mutation in both alleles, however the lack of clinical symptoms and correct sweat testing values did not lead doctors to diagnosing cystic fibrosis and by the same token implementing the treatment. The analysis encompassed a group of 22 infants and children 3 months to 3 years of age, in whom, in spite of a positive result of newborn screening for cystic fibrosis and the presence of 2 mutations in the CFTR gene, the diagnosis of cystic fibrosis was not made, and appropriate treatment was not administered because of diagnostic doubts (due to correct concentration of chlorides in sweat, correct IRT level and lack of clinical signs of cystic fibrosis). The control group consisted of 55 children treated in our centre, in whom neonatal screening for cystic fibrosis was positive and the diagnosis was confirmed by genetic testing, sweat chloride testing and IRT concentration. There were no differences in birth body weight between the groups. The differences in chlorideion levels in sweat secretion tests and mean IRT values were statistically significant and were: 97.5 for the control group and 26.4 for the test group. At the present time there are no clinical symptoms to give a diagnosis of cystic fibrosis and start treatment in the test group. Newborn screening contributes not only to an early diagnosis of cystic fibrosis but also to CFTR-related metabolic syndromes (CRMS), which is a phenomenon requiring further observation. This fact constitutes a definite psychological problem for the parents of these patients. .

The Organization of Controller Motifs Leading to Robust Plant Iron Homeostasis

PubMed Central

Agafonov, Oleg; Selstø, Christina Helen; Thorsen, Kristian; Xu, Xiang Ming; Drengstig, Tormod; Ruoff, Peter

2016-01-01

Iron is an essential element needed by all organisms for growth and development. Because iron becomes toxic at higher concentrations iron is under homeostatic control. Plants face also the problem that iron in the soil is tightly bound to oxygen and difficult to access. Plants have therefore developed special mechanisms for iron uptake and regulation. During the last years key components of plant iron regulation have been identified. How these components integrate and maintain robust iron homeostasis is presently not well understood. Here we use a computational approach to identify mechanisms for robust iron homeostasis in non-graminaceous plants. In comparison with experimental results certain control arrangements can be eliminated, among them that iron homeostasis is solely based on an iron-dependent degradation of the transporter IRT1. Recent IRT1 overexpression experiments suggested that IRT1-degradation is iron-independent. This suggestion appears to be misleading. We show that iron signaling pathways under IRT1 overexpression conditions become saturated, leading to a breakdown in iron regulation and to the observed iron-independent degradation of IRT1. A model, which complies with experimental data places the regulation of cytosolic iron at the transcript level of the transcription factor FIT. Including the experimental observation that FIT induces inhibition of IRT1 turnover we found a significant improvement in the system’s response time, suggesting a functional role for the FIT-mediated inhibition of IRT1 degradation. By combining iron uptake with storage and remobilization mechanisms a model is obtained which in a concerted manner integrates iron uptake, storage and remobilization. In agreement with experiments the model does not store iron during its high-affinity uptake. As an iron biofortification approach we discuss the possibility how iron can be accumulated even during high-affinity uptake. PMID:26800438

Genetic and clinical features of false-negative infants in a neonatal screening programme for cystic fibrosis.

PubMed

Padoan, R; Genoni, S; Moretti, E; Seia, M; Giunta, A; Corbetta, C

2002-01-01

A study was performed on the delayed diagnosis of cystic fibrosis (CF) in infants who had false-negative results in a neonatal screening programme. The genetic and clinical features of false-negative infants in this screening programme were assessed together with the efficiency of the screening procedure in the Lombardia region. In total, 774,687 newborns were screened using a two-step immunoreactive trypsinogen (IRT) (in the years 1990-1992), IRT/IRT + delF508 (1993-1998) or IRT/IRT + polymerase chain reaction (PCR) and oligonucleotide ligation assay (OLA) protocol (1998-1999). Out of 196 CF children born in the 10 y period 15 were false negative on screening (7.6%) and molecular analysis showed a high variability in the genotypes. The cystic fibrosis transmembrane regulator (CFTR) gene mutations identified were delF508, D1152H, R1066C, R334W, G542X, N1303K, F1052V, A120T, 3849 + 10kbC --> T, 2789 + 5G --> A, 5T-12TG and the novel mutation D110E. In three patients no mutation was identified after denaturing gradient gel electrophoresis of the majority of CFTR gene exons. The clinical phenotypes of CF children diagnosed by their symptoms at different ages were very mild. None of them presented with a severe lung disease. The majority of them did not seem to have been damaged by the delayed diagnosis. The combination of IRT assay plus genotype analysis (1998-1999) appears to be a more reliable method of detecting CF than IRT measurement alone or combined with only the delF508 mutation.

Evidence for a causal relationship between early exocrine pancreatic disease and cystic fibrosis-related diabetes: a Mendelian randomization study.

PubMed

Soave, David; Miller, Melissa R; Keenan, Katherine; Li, Weili; Gong, Jiafen; Ip, Wan; Accurso, Frank; Sun, Lei; Rommens, Johanna M; Sontag, Marci; Durie, Peter R; Strug, Lisa J

2014-06-01

Circulating immunoreactive trypsinogen (IRT), a biomarker of exocrine pancreatic disease in cystic fibrosis (CF), is elevated in most CF newborns. In those with severe CF transmembrane conductance regulator (CFTR) genotypes, IRT declines rapidly in the first years of life, reflecting progressive pancreatic damage. Consistent with this progression, a less elevated newborn IRT measure would reflect more severe pancreatic disease, including compromised islet compartments, and potentially increased risk of CF-related diabetes (CFRD). We show in two independent CF populations that a lower newborn IRT estimate is associated with higher CFRD risk among individuals with severe CFTR genotypes, and we provide evidence to support a causal relationship. Increased loge(IRT) at birth was associated with decreased CFRD risk in Canadian and Colorado samples (hazard ratio 0.30 [95% CI 0.15-0.61] and 0.39 [0.18-0.81], respectively). Using Mendelian randomization with the SLC26A9 rs7512462 genotype as an instrumental variable since it is known to be associated with IRT birth levels in the CF population, we provide evidence to support a causal contribution of exocrine pancreatic status on CFRD risk. Our findings suggest CFRD risk could be predicted in early life and that maintained ductal fluid flow in the exocrine pancreas could delay the onset of CFRD. © 2014 by the American Diabetes Association.

Job Satisfaction of University Faculty.

ERIC Educational Resources Information Center

Onuoha, Alphonso R. A.

1980-01-01

In testing Herzberg's two-factor theory of job satisfaction, it was found that theories of job satisfaction may be closely related to the methods used in collecting data; hence, the results of studies employing different methods raise questions about the validity of a particular theory. (Author/IRT)

Leadership Effectiveness in Teacher Probation Committees

ERIC Educational Resources Information Center

Martin, Yvonne M.; And Others

1976-01-01

This study tested the prediction of Fiedler's Contingency Theory of Leadership Effectiveness, namely, that a relationship-oriented leadership style would lead to task-group effectiveness in a moderately favorable situation, while a task-oriented leadership style would lead to effectiveness in an unfavorable situation. (Author/IRT)

Item response theory detects differential item functioning between healthy and ill children in QoL measures

PubMed Central

Langer, Michelle M.; Hill, Cheryl D.; Thissen, David; Burwinkle, Tasha M.; Varni, James W.; DeWalt, Darren A.

2008-01-01

Objective To demonstrate the value of item response theory (IRT) and differential item functioning (DIF) methods in examining a health-related quality of life (HRQOL) measure in children and adolescents. Study Design and Setting This illustration uses data from 5,429 children using the four subscales of the PedsQL™ 4.0 Generic Core Scales. The IRT model-based likelihood ratio test was used to detect and evaluate DIF between healthy children and children with a chronic condition. Results DIF was detected for a majority of items but cancelled out at the total test score level due to opposing directions of DIF. Post-hoc analysis indicated that this pattern of results may be due to multidimensionality. We discuss issues in detecting and handling DIF. Conclusion This paper describes how to perform DIF analyses in validating a questionnaire to ensure that scores have equivalent meaning across subgroups. It offers insight into ways information gained through the analysis can be used to evaluate an existing scale. PMID:18226750

Fit of Item Response Theory Models: A Survey of Data from Several Operational Tests. Research Report. ETS RR-11-29

ERIC Educational Resources Information Center

Sinharay, Sandip; Haberman, Shelby J.; Jia, Helena

2011-01-01

Standard 3.9 of the "Standards for Educational and Psychological Testing" (American Educational Research Association, American Psychological Association, & National Council for Measurement in Education, 1999) demands evidence of model fit when an item response theory (IRT) model is used to make inferences from a data set. We applied two recently…

A Comparison of Item Exposure Control Procedures with the Generalized Partial Credit Model

ERIC Educational Resources Information Center

Sanchez, Edgar Isaac

2008-01-01

To enhance test security of high stakes tests, it is vital to understand the way various exposure control strategies function under various IRT models. To that end the present dissertation focused on the performance of several exposure control strategies under the generalized partial credit model with an item pool of 100 and 200 items. These…

An Item Response Theory-Based, Computerized Adaptive Testing Version of the MacArthur-Bates Communicative Development Inventory: Words & Sentences (CDI:WS)

ERIC Educational Resources Information Center

Makransky, Guido; Dale, Philip S.; Havmose, Philip; Bleses, Dorthe

2016-01-01

Purpose: This study investigated the feasibility and potential validity of an item response theory (IRT)-based computerized adaptive testing (CAT) version of the MacArthur-Bates Communicative Development Inventory: Words & Sentences (CDI:WS; Fenson et al., 2007) vocabulary checklist, with the objective of reducing length while maintaining…

Lord-Wingersky Algorithm Version 2.0 for Hierarchical Item Factor Models with Applications in Test Scoring, Scale Alignment, and Model Fit Testing. CRESST Report 830

ERIC Educational Resources Information Center

Cai, Li

2013-01-01

Lord and Wingersky's (1984) recursive algorithm for creating summed score based likelihoods and posteriors has a proven track record in unidimensional item response theory (IRT) applications. Extending the recursive algorithm to handle multidimensionality is relatively simple, especially with fixed quadrature because the recursions can be defined…

The Motivational Value Systems Questionnaire (MVSQ): Psychometric Analysis Using a Forced Choice Thurstonian IRT Model

PubMed Central

Merk, Josef; Schlotz, Wolff; Falter, Thomas

2017-01-01

This study presents a new measure of value systems, the Motivational Value Systems Questionnaire (MVSQ), which is based on a theory of value systems by psychologist Clare W. Graves. The purpose of the instrument is to help people identify their personal hierarchies of value systems and thus become more aware of what motivates and demotivates them in work-related contexts. The MVSQ is a forced-choice (FC) measure, making it quicker to complete and more difficult to intentionally distort, but also more difficult to assess its psychometric properties due to ipsativity of FC data compared to rating scales. To overcome limitations of ipsative data, a Thurstonian IRT (TIRT) model was fitted to the questionnaire data, based on a broad sample of N = 1,217 professionals and students. Comparison of normative (IRT) scale scores and ipsative scores suggested that MVSQ IRT scores are largely freed from restrictions due to ipsativity and thus allow interindividual comparison of scale scores. Empirical reliability was estimated using a sample-based simulation approach which showed acceptable and good estimates and, on average, slightly higher test-retest reliabilities. Further, validation studies provided evidence on both construct validity and criterion-related validity. Scale score correlations and associations of scores with both age and gender were largely in line with theoretically- and empirically-based expectations, and results of a multitrait-multimethod analysis supports convergent and discriminant construct validity. Criterion validity was assessed by examining the relation of value system preferences to departmental affiliation which revealed significant relations in line with prior hypothesizing. These findings demonstrate the good psychometric properties of the MVSQ and support its application in the assessment of value systems in work-related contexts. PMID:28979228

The Motivational Value Systems Questionnaire (MVSQ): Psychometric Analysis Using a Forced Choice Thurstonian IRT Model.

PubMed

Merk, Josef; Schlotz, Wolff; Falter, Thomas

2017-01-01

This study presents a new measure of value systems, the Motivational Value Systems Questionnaire (MVSQ), which is based on a theory of value systems by psychologist Clare W. Graves. The purpose of the instrument is to help people identify their personal hierarchies of value systems and thus become more aware of what motivates and demotivates them in work-related contexts. The MVSQ is a forced-choice (FC) measure, making it quicker to complete and more difficult to intentionally distort, but also more difficult to assess its psychometric properties due to ipsativity of FC data compared to rating scales. To overcome limitations of ipsative data, a Thurstonian IRT (TIRT) model was fitted to the questionnaire data, based on a broad sample of N = 1,217 professionals and students. Comparison of normative (IRT) scale scores and ipsative scores suggested that MVSQ IRT scores are largely freed from restrictions due to ipsativity and thus allow interindividual comparison of scale scores. Empirical reliability was estimated using a sample-based simulation approach which showed acceptable and good estimates and, on average, slightly higher test-retest reliabilities. Further, validation studies provided evidence on both construct validity and criterion-related validity. Scale score correlations and associations of scores with both age and gender were largely in line with theoretically- and empirically-based expectations, and results of a multitrait-multimethod analysis supports convergent and discriminant construct validity. Criterion validity was assessed by examining the relation of value system preferences to departmental affiliation which revealed significant relations in line with prior hypothesizing. These findings demonstrate the good psychometric properties of the MVSQ and support its application in the assessment of value systems in work-related contexts.

Better assessment of physical function: item improvement is neglected but essential

PubMed Central

2009-01-01

Introduction Physical function is a key component of patient-reported outcome (PRO) assessment in rheumatology. Modern psychometric methods, such as Item Response Theory (IRT) and Computerized Adaptive Testing, can materially improve measurement precision at the item level. We present the qualitative and quantitative item-evaluation process for developing the Patient Reported Outcomes Measurement Information System (PROMIS) Physical Function item bank. Methods The process was stepwise: we searched extensively to identify extant Physical Function items and then classified and selectively reduced the item pool. We evaluated retained items for content, clarity, relevance and comprehension, reading level, and translation ease by experts and patient surveys, focus groups, and cognitive interviews. We then assessed items by using classic test theory and IRT, used confirmatory factor analyses to estimate item parameters, and graded response modeling for parameter estimation. We retained the 20 Legacy (original) Health Assessment Questionnaire Disability Index (HAQ-DI) and the 10 SF-36's PF-10 items for comparison. Subjects were from rheumatoid arthritis, osteoarthritis, and healthy aging cohorts (n = 1,100) and a national Internet sample of 21,133 subjects. Results We identified 1,860 items. After qualitative and quantitative evaluation, 124 newly developed PROMIS items composed the PROMIS item bank, which included revised Legacy items with good fit that met IRT model assumptions. Results showed that the clearest and best-understood items were simple, in the present tense, and straightforward. Basic tasks (like dressing) were more relevant and important versus complex ones (like dancing). Revised HAQ-DI and PF-10 items with five response options had higher item-information content than did comparable original Legacy items with fewer response options. IRT analyses showed that the Physical Function domain satisfied general criteria for unidimensionality with one-, two-, three-, and four-factor models having comparable model fits. Correlations between factors in the test data sets were > 0.90. Conclusions Item improvement must underlie attempts to improve outcome assessment. The clear, personally important and relevant, ability-framed items in the PROMIS Physical Function item bank perform well in PRO assessment. They will benefit from further study and application in a wider variety of rheumatic diseases in diverse clinical groups, including those at the extremes of physical functioning, and in different administration modes. PMID:20015354

Better assessment of physical function: item improvement is neglected but essential.

PubMed

Bruce, Bonnie; Fries, James F; Ambrosini, Debbie; Lingala, Bharathi; Gandek, Barbara; Rose, Matthias; Ware, John E

2009-01-01

Physical function is a key component of patient-reported outcome (PRO) assessment in rheumatology. Modern psychometric methods, such as Item Response Theory (IRT) and Computerized Adaptive Testing, can materially improve measurement precision at the item level. We present the qualitative and quantitative item-evaluation process for developing the Patient Reported Outcomes Measurement Information System (PROMIS) Physical Function item bank. The process was stepwise: we searched extensively to identify extant Physical Function items and then classified and selectively reduced the item pool. We evaluated retained items for content, clarity, relevance and comprehension, reading level, and translation ease by experts and patient surveys, focus groups, and cognitive interviews. We then assessed items by using classic test theory and IRT, used confirmatory factor analyses to estimate item parameters, and graded response modeling for parameter estimation. We retained the 20 Legacy (original) Health Assessment Questionnaire Disability Index (HAQ-DI) and the 10 SF-36's PF-10 items for comparison. Subjects were from rheumatoid arthritis, osteoarthritis, and healthy aging cohorts (n = 1,100) and a national Internet sample of 21,133 subjects. We identified 1,860 items. After qualitative and quantitative evaluation, 124 newly developed PROMIS items composed the PROMIS item bank, which included revised Legacy items with good fit that met IRT model assumptions. Results showed that the clearest and best-understood items were simple, in the present tense, and straightforward. Basic tasks (like dressing) were more relevant and important versus complex ones (like dancing). Revised HAQ-DI and PF-10 items with five response options had higher item-information content than did comparable original Legacy items with fewer response options. IRT analyses showed that the Physical Function domain satisfied general criteria for unidimensionality with one-, two-, three-, and four-factor models having comparable model fits. Correlations between factors in the test data sets were > 0.90. Item improvement must underlie attempts to improve outcome assessment. The clear, personally important and relevant, ability-framed items in the PROMIS Physical Function item bank perform well in PRO assessment. They will benefit from further study and application in a wider variety of rheumatic diseases in diverse clinical groups, including those at the extremes of physical functioning, and in different administration modes.

Psychometric properties for the Balanced Inventory of Desirable Responding: dichotomous versus polytomous conventional and IRT scoring.

PubMed

Vispoel, Walter P; Kim, Han Yi

2014-09-01

[Correction Notice: An Erratum for this article was reported in Vol 26(3) of Psychological Assessment (see record 2014-16017-001). The mean, standard deviation and alpha coefficient originally reported in Table 1 should be 74.317, 10.214 and .802, respectively. The validity coefficients in the last column of Table 4 are affected as well. Correcting this error did not change the substantive interpretations of the results, but did increase the mean, standard deviation, alpha coefficient, and validity coefficients reported for the Honesty subscale in the text and in Tables 1 and 4. The corrected versions of Tables 1 and Table 4 are shown in the erratum.] Item response theory (IRT) models were applied to dichotomous and polytomous scoring of the Self-Deceptive Enhancement and Impression Management subscales of the Balanced Inventory of Desirable Responding (Paulhus, 1991, 1999). Two dichotomous scoring methods reflecting exaggerated endorsement and exaggerated denial of socially desirable behaviors were examined. The 1- and 2-parameter logistic models (1PLM, 2PLM, respectively) were applied to dichotomous responses, and the partial credit model (PCM) and graded response model (GRM) were applied to polytomous responses. For both subscales, the 2PLM fit dichotomous responses better than did the 1PLM, and the GRM fit polytomous responses better than did the PCM. Polytomous GRM and raw scores for both subscales yielded higher test-retest and convergent validity coefficients than did PCM, 1PLM, 2PLM, and dichotomous raw scores. Information plots showed that the GRM provided consistently high measurement precision that was superior to that of all other IRT models over the full range of both construct continuums. Dichotomous scores reflecting exaggerated endorsement of socially desirable behaviors provided noticeably weak precision at low levels of the construct continuums, calling into question the use of such scores for detecting instances of "faking bad." Dichotomous models reflecting exaggerated denial of the same behaviors yielded much better precision at low levels of the constructs, but it was still less precision than that of the GRM. These results support polytomous over dichotomous scoring in general, alternative dichotomous scoring for detecting faking bad, and extension of GRM scoring to situations in which IRT offers additional practical advantages over classical test theory (adaptive testing, equating, linking, scaling, detecting differential item functioning, and so forth). PsycINFO Database Record (c) 2014 APA, all rights reserved.

Caffeine use disorder: An item-response theory analysis of proposed DSM-5 criteria.

PubMed

Ágoston, Csilla; Urbán, Róbert; Richman, Mara J; Demetrovics, Zsolt

2018-06-01

Caffeine is a common psychoactive substance with a documented addictive potential. Caffeine withdrawal has been included in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), but caffeine use disorder (CUD) is considered to be a condition for further study. The aim of the current study is (1) to test the psychometric properties of the Caffeine Use Disorder Questionnaire (CUDQ) by using a confirmatory factor analysis and an item response theory (IRT) approach, (2) to compare IRT models with varying numbers of parameters and models with or without caffeine consumption criteria, and (3) to examine if the total daily caffeine consumption and the use of different caffeinated products can predict the magnitude of CUD symptomatology. A cross-sectional study was conducted on an adult sample (N = 2259). Participants answered several questions regarding their caffeine consumption habits and completed the CUDQ, which incorporates the nine proposed criteria of the DSM-5 as well as one additional item regarding the suffering caused by the symptoms. Factor analyses demonstrated the unidimensionality of the CUDQ. The suffering criterion had the highest discriminative value at a higher degree of latent trait. The criterion of failure to fulfill obligations and social/interpersonal problems discriminate only at the higher value of CUD latent factor, while endorsement the consumption of more caffeine or longer than intended and craving criteria were discriminative at a lower level of CUD. Total daily caffeine intake was related to a higher level of CUD. Daily coffee, energy drink, and cola intake as dummy variables were associated with the presence of more CUD symptoms, while daily tea consumption as a dummy variable was related to less CUD symptoms. Regular smoking was associated with more CUD symptoms, which was explained by a larger caffeine consumption. The IRT approach helped to determine which CUD symptoms indicate more severity and have a greater discriminative value. The level of CUD is influenced by the type and quantity of caffeine consumption. Copyright © 2018 Elsevier Ltd. All rights reserved.

Development and validation of PediaTrac™: A web-based tool to track developing infants.

PubMed

Lajiness-O'Neill, Renée; Brooks, Judith; Lukomski, Angela; Schilling, Stephen; Huth-Bocks, Alissa; Warschausky, Seth; Flores, Ana-Mercedes; Swick, Casey; Nyman, Tristin; Andersen, Tiffany; Morris, Natalie; Schmitt, Thomas A; Bell-Smith, Jennifer; Moir, Barbara; Hodges, Elise K; Lyddy, James E

2018-02-01

PediaTrac™, a 363-item web-based tool to track infant development, administered in modules of ∼40-items per sampling period, newborn (NB), 2--, 4--, 6--, 9-- and 12--months was validated. Caregivers answered demographic, medical, and environmental questions, and questions covering the sensorimotor, feeding/eating, sleep, speech/language, cognition, social-emotional, and attachment domains. Expert Panel Reviews and Cognitive Interviews (CI) were conducted to validate the item bank. Classical Test Theory (CTT) and Item Response Theory (IRT) methods were employed to examine the dimensionality and psychometric properties of PediaTrac with pooled longitudinal and cross-sectional cohorts (N = 132). Intraclass correlation coefficients (ICC) for the Expert Panel Review revealed moderate agreement at 6 -months and good reliability at other sampling periods. ICC estimates for CI revealed moderate reliability regarding clarity of the items at NB and 4 months, good reliability at 2--, 9-- and 12--months and excellent reliability at 6 -months. CTT revealed good coefficient alpha estimates (α ≥ 0.77 for five of the six ages) for the Social-Emotional/Communication, Attachment (α ≥ 0.89 for all ages), and Sensorimotor (α ≥ 0.75 at 6-months) domains, revealing the need for better targeting of sensorimotor items. IRT modeling revealed good reliability (r = 0.85-0.95) for three distinct domains (Feeding/Eating, Social-Emotional/Communication and Attachment) and four subdomains (Feeding Breast/Formula, Feeding Solid Food, Social-Emotional Information Processing, Communication/Cognition). Convergent and discriminant construct validity were demonstrated between our IRT-modeled domains and constructs derived from existing developmental, behavioral and caregiver measures. Our Attachment domain was significantly correlated with existing measures at the NB and 2-month periods, while the Social-Emotional/Communication domain was highly correlated with similar constructs at the 6-, 9- and 12-month periods. PediaTrac has potential for producing novel and effective estimates of infant development via the Sensorimotor, Feeding/Eating, Social-Emotional/Communication and Attachment domains. Copyright © 2018 Elsevier Inc. All rights reserved.

Forecasting the Movement of Educational Administrators Through Vacancy Flows

ERIC Educational Resources Information Center

Brown, Daniel J.

1976-01-01

Discusses the problem of forecasting manpower flows in administrative hierarchies of educational organizations, reviews groups of manpower models, discusses characteristics of administrative hierarchies and the vacancy model as it relates to those characteristics, and carries out validation and projective tests of the model. (Author/IRT)

Heat transfer measurements from a NACA 0012 airfoil in flight and in the NASA Lewis icing research tunnel. M.S. Thesis Final Report

NASA Technical Reports Server (NTRS)

Poinsatte, Philip E.

1990-01-01

Local heat transfer coefficients from a smooth and roughened NACA 0012 airfoil were measured using a steady state heat flux method. Heat transfer measurements on the specially constructed 0.533 meter chord airfoil were made both in flight on the NASA Lewis Twin Otter Research Aircraft and in the NASA Lewis Icing Research Tunnel (IRT). Roughness was obtained by the attachment of small, 2 mm diameter, hemispheres of uniform size to the airfoil surface in four distinct patterns. The flight data was taken for the smooth and roughened airfoil at various Reynolds numbers based on chord in the range of 1.24x10(exp 6) to 2.50x10(exp 6) and at various angles of attack up to 4 degrees. During these flight tests the free stream velocity turbulence intensity was found to be very low (less than 0.1 percent). The wind tunnel data was taken in the Reynolds number range of 1.20x10(exp 6) to 4.52x10(exp 6) and at angles of attack from -4 degrees to +8 degrees. The turbulence intensity in the IRT was 0.5 to 0.7 percent with the cloud making spray off. Results for both the flight and tunnel tests are presented as Frossling number based on chord versus position on the airfoil surface for various roughnesses and angle of attack. A table of power law curve fits of Nusselt number as a function of Reynolds number is also provided. The higher level of turbulence in the IRT versus flight had little effect on heat transfer for the lower Reynolds numbers but caused a moderate increase in heat transfer at the higher Reynolds numbers. Turning on the cloud making spray air in the IRT did not alter the heat transfer. Roughness generally increased the heat transfer by locally disturbing the boundary layer flow. Finally, the present data was not only compared with previous airfoil data where applicable, but also with leading edge cylinder and flat plate heat transfer values which are often used to estimate airfoil heat transfer in computer codes.

An item response curves analysis of the Force Concept Inventory

NASA Astrophysics Data System (ADS)

Morris, Gary A.; Harshman, Nathan; Branum-Martin, Lee; Mazur, Eric; Mzoughi, Taha; Baker, Stephen D.

2012-09-01

Several years ago, we introduced the idea of item response curves (IRC), a simplistic form of item response theory (IRT), to the physics education research community as a way to examine item performance on diagnostic instruments such as the Force Concept Inventory (FCI). We noted that a full-blown analysis using IRT would be a next logical step, which several authors have since taken. In this paper, we show that our simple approach not only yields similar conclusions in the analysis of the performance of items on the FCI to the more sophisticated and complex IRT analyses but also permits additional insights by characterizing both the correct and incorrect answer choices. Our IRC approach can be applied to a variety of multiple-choice assessments but, as applied to a carefully designed instrument such as the FCI, allows us to probe student understanding as a function of ability level through an examination of each answer choice. We imagine that physics teachers could use IRC analysis to identify prominent misconceptions and tailor their instruction to combat those misconceptions, fulfilling the FCI authors' original intentions for its use. Furthermore, the IRC analysis can assist test designers to improve their assessments by identifying nonfunctioning distractors that can be replaced with distractors attractive to students at various ability levels.

The Montgomery Äsberg and the Hamilton Ratings of Depression

PubMed Central

Carmody, Thomas; Rush, A. John; Bernstein, Ira; Warden, Diane; Brannan, Stephen; Burnham, Daniel; Woo, Ada; Trivedi, Madhukar

2007-01-01

The 17-item Hamilton Rating Scale for Depression (HRSD17) and the Montgomery Äsberg Depression Rating Scale (MADRS) are two widely used clinicianrated symptom scales. A 6-item version of the HRSD (HRSD6) was created by Bech to address the psychometric limitations of the HRSD17. The psychometric properties of these measures were compared using classical test theory (CTT) and item response theory (IRT) methods. IRT methods were used to equate total scores on any two scales. Data from two distinctly different outpatient studies of nonpsychotic major depression: a 12-month study of highly treatment-resistant patients (n=233) and an 8-week acute phase drug treatment trial (n=985) were used for robustness of results. MADRS and HRSD6 items generally contributed more to the measurement of depression than HRSD17 items as shown by higher item-total correlations and higher IRT slope parameters. The MADRS and HRSD6 were unifactorial while the HRSD17 contained 2 factors. The MADRS showed about twice the precision in estimating depression as either the HRSD17 or HRSD6 for average severity of depression. An HRSD17 of 7 corresponded to an 8 or 9 on the MADRS and 4 on the HRSD6. The MADRS would be superior to the HRSD17 in the conduct of clinical trials. PMID:16769204

Perfluorochemical (PFC) Exposure in Children: Associations with Impaired Response Inhibition

PubMed Central

Gump, Brooks B.; Wu, Qian; Dumas, Amy K.; Kannan, Kurunthachalam

2011-01-01

Background Perfluorinated chemicals (PFCs) have been used widely in consumer products since the 1950s and are currently found at detectable levels in the blood of humans and animals across the globe. In stark contrast to this widespread exposure to PFCs, there is relatively little research on potential adverse health effects of exposure to these chemicals. Objectives We performed this cross-sectional study to determine if specific blood PFC levels are associated with impaired response inhibition in children. Methods Blood levels of 11 PFCs were measured in children (N = 83) and 6 PFCs: perfluorooctane sulfonate (PFOS), perfluorohexane sulfate (PFHxS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorooctanesulfonamide (PFOSA), and perfluorodecanoic acid (PFDA) – were found at detectable levels in most children (87.5% or greater had detectable levels). These levels were analyzed in relation to the differential reinforcement of low rates of responding (DRL) task. This task rewards delays between responses (i.e., longer inter-response times; IRTs) and therefore constitutes a measure of response inhibition. Results Higher levels of blood PFOS, PFNA, PFDA, PFHxS, and PFOSA were associated with significantly shorter IRTs during the DRL task. The magnitude of these associations was such that IRTs during the task decreased by 29–34% for every 1 SD increase in the corresponding blood PFC. Conclusions This study suggests an association between PFC exposure and children’s impulsivity. Although intriguing, there is a need for further investigation and replication with a larger sample of children. PMID:21682250

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

Huml, O.

The objective of this work was to determine the neutron flux density distribution in various places of the training reactor VR-1 Sparrow. This experiment was performed on the new core design C1, composed of the new low-enriched uranium fuel cells IRT-4M (19.7 %). This fuel replaced the old high-enriched uranium fuel IRT-3M (36 %) within the framework of the RERTR Program in September 2005. The measurement used the neutron activation analysis method with gold wires. The principle of this method consists in neutron capture in a nucleus of the material forming the activation detector. This capture can change the nucleusmore » in a radioisotope, whose activity can be measured. The absorption cross-section values were evaluated by MCNP computer code. The gold wires were irradiated in seven different positions in the core C1. All irradiations were performed at reactor power level 1E8 (1 kW{sub therm}). The activity of segments of irradiated wires was measured by special automatic device called 'Drat' (Wire in English). (author)« less

Instability resistance training across the exercise continuum.

PubMed

Behm, David G; Colado, Juan C; Colado, Juan C

2013-11-01

Instability resistance training (IRT; unstable surfaces and devices to strengthen the core or trunk muscles) is popular in fitness training facilities. To examine contradictory IRT recommendations for health enthusiasts and rehabilitation. A literature search was performed using MEDLINE, SPORT Discus, ScienceDirect, Web of Science, and Google Scholar databases from 1990 to 2012. Databases were searched using key terms, including "balance," "stability," "instability," "resistance training," "core," "trunk," and "functional performance." Additionally, relevant articles were extracted from reference lists. To be included, research questions addressed the effect of balance or IRT on performance, healthy and active participants, and physiologic or performance outcome measures and had to be published in English in a peer-reviewed journal. There is a dichotomy of opinions on the effectiveness and application of instability devices and conditions for health and performance training. Balance training without resistance has been shown to improve not only balance but functional performance as well. IRT studies document similar training adaptations as stable resistance training programs with recreationally active individuals. Similar progressions with lower resistance may improve balance and stability, increase core activation, and improve motor control. IRT is highly recommended for youth, elderly, recreationally active individuals, and highly trained enthusiasts.

Assessing First- and Second-Order Equity for the Common-Item Nonequivalent Groups Design Using Multidimensional IRT

ERIC Educational Resources Information Center

Andrews, Benjamin James

2011-01-01

The equity properties can be used to assess the quality of an equating. The degree to which expected scores conditional on ability are similar between test forms is referred to as first-order equity. Second-order equity is the degree to which conditional standard errors of measurement are similar between test forms after equating. The purpose of…

The Langer-Improved Wald Test for DIF Testing with Multiple Groups: Evaluation and Comparison to Two-Group IRT

ERIC Educational Resources Information Center

Woods, Carol M.; Cai, Li; Wang, Mian

2013-01-01

Differential item functioning (DIF) occurs when the probability of responding in a particular category to an item differs for members of different groups who are matched on the construct being measured. The identification of DIF is important for valid measurement. This research evaluates an improved version of Lord's chi [superscript 2]…

IRT Analysis of General Outcome Measures in Grades 1-8. Technical Report # 0916

ERIC Educational Resources Information Center

Alonzo, Julie; Anderson, Daniel; Tindal, Gerald

2009-01-01

We present scaling outcomes for mathematics assessments used in the fall to screen students at risk of failing to learn the knowledge and skills described in the National Council of Teachers of Mathematics (NCTM) Focal Point Standards. At each grade level, the assessment consisted of a 48-item test with three 16-item sub-test sets aligned to the…

Item Selection for the Development of Parallel Forms from an IRT-Based Seed Test Using a Sampling and Classification Approach

ERIC Educational Resources Information Center

Chen, Pei-Hua; Chang, Hua-Hua; Wu, Haiyan

2012-01-01

Two sampling-and-classification-based procedures were developed for automated test assembly: the Cell Only and the Cell and Cube methods. A simulation study based on a 540-item bank was conducted to compare the performance of the procedures with the performance of a mixed-integer programming (MIP) method for assembling multiple parallel test…

Evaluation of Linking Methods for Placing Three-Parameter Logistic Item Parameter Estimates onto a One-Parameter Scale

ERIC Educational Resources Information Center

Karkee, Thakur B.; Wright, Karen R.

2004-01-01

Different item response theory (IRT) models may be employed for item calibration. Change of testing vendors, for example, may result in the adoption of a different model than that previously used with a testing program. To provide scale continuity and preserve cut score integrity, item parameter estimates from the new model must be linked to the…

Handbook of Polytomous Item Response Theory Models

ERIC Educational Resources Information Center

Nering, Michael L., Ed.; Ostini, Remo, Ed.

2010-01-01

This comprehensive "Handbook" focuses on the most used polytomous item response theory (IRT) models. These models help us understand the interaction between examinees and test questions where the questions have various response categories. The book reviews all of the major models and includes discussions about how and where the models…

A Comparison of Four Methods of IRT Subscoring

ERIC Educational Resources Information Center

de la Torre, Jimmy; Song, Hao; Hong, Yuan

2011-01-01

Lack of sufficient reliability is the primary impediment for generating and reporting subtest scores. Several current methods of subscore estimation do so either by incorporating the correlational structure among the subtest abilities or by using the examinee's performance on the overall test. This article conducted a systematic comparison of four…

The Discriminating Power of Items that Measure More than One Dimension.

ERIC Educational Resources Information Center

Reckase, Mark D.

The work presented in this paper defined conceptually the concepts of multidimensional discrimination and information, derived mathematical expressions for the concepts for a particular multidimensional item response theory (IRT) model, and applied the concepts to actual test data. Multidimensional discrimination was defined as a function of the…

Educational Malpractice and Minimal Competency Testing: Is There a Legal Remedy at Last?

ERIC Educational Resources Information Center

Pabian, Jay M.

1979-01-01

Examines the ineffectiveness of common law action in negligence suits and the effectiveness of state legislation to eliminate educational malpractice and functional illiteracy. Suggests alternative ways to prove educational malpractice. Available from New England Law Review, 126 Newbury St., Boston, MA 02116. (IRT)

Does computerizing paper-and-pencil job attitude scales make a difference? New IRT analyses offer insight.

PubMed

Donovan, M A; Drasgow, F; Probst, T M

2000-04-01

The measurement equivalence of 2 scales of the Job Descriptive Index (JDI; P. C. Smith, L. M. Kendall, & C. L. Hulin, 1969), the Supervisor Satisfaction scale and the Coworker Satisfaction scale, was examined across computerized and paper-and-pencil administrations. In this study, employees in 2 organizations (N = 1,777) were administered paper-and-pencil versions of the scales, and employees in a third organization (N = 509) were administered a computerized version. A newly developed item response theory (IRT) technique for examining differential test functioning (N. S. Raju, W. J. van der Linden, & P. F. Fleer, 1995) was used to examine measurement equivalence across media. Results support the measurement equivalence of the JDI Supervisor and Coworker scales across administration media. The implications of these findings for both practitioners and organizational researchers are discussed.

The therapeutic factor inventory-8: Using item response theory to create a brief scale for continuous process monitoring for group psychotherapy.

PubMed

Tasca, Giorgio A; Cabrera, Christine; Kristjansson, Elizabeth; MacNair-Semands, Rebecca; Joyce, Anthony S; Ogrodniczuk, John S

2016-01-01

We tested a very brief version of the 23-item Therapeutic Factors Inventory-Short Form (TFI-S), and describe the use of Item Response Theory (IRT) for the purpose of developing short and reliable scales for group psychotherapy. Group therapy patients (N = 578) completed the TFI-S on one occasion, and their data were used for the IRT analysis. Of those, 304 completed the TFI-S and other measures on more than one occasion to assess sensitivity to change, concurrent, and predictive validity of the brief version. Results suggest that the new TFI-8 is a brief, reliable, and valid measure of a higher-order group therapeutic factor. The TFI-8 may be used for continuous process measurement and feedback to improve the functioning of therapy groups.

Intensive remote monitoring versus conventional care in type 1 diabetes: A randomized controlled trial.

PubMed

Gandrud, Laura; Altan, Aylin; Buzinec, Paul; Hemphill, Jesse; Chatterton, Jayne; Kelley, Tina; Vojta, Deneen

2018-02-21

While frequent contact with diabetes care providers may improve glycemic control among patients with type 1 diabetes (T1D), in-person visits are labor-intensive and costly. This study was conducted to assess the impact of an intensive remote therapy (IRT) intervention for pediatric patients with T1D. Pediatric patients with T1D were randomized to IRT or conventional care (CC) for 6 months. Both cohorts continued routine quarterly clinic visits and uploaded device data; for the IRT cohort, data were reviewed and patients were contacted if regimen adjustments were indicated. Glycated hemoglobin (HbA1c) change from baseline was assessed at 6 and 9 months. Diabetes-related quality of life (QoL), healthcare services utilization, and hypoglycemic events were also tracked. Among 117 enrollees (60 IRT, 57 CC), mean (SD) 6-month %HbA1c change for IRT vs CC was -0.34 (0.85) (-3.7 mmol/mol) vs -0.05 (0.74) (-0.5 mmol/mol) overall (P = .071); -0.15 (0.67) (1.6 mmol/mol) vs -0.02 (0.66) (0.2 mmol/mol) for ages 8 to 12 (P = .541); and -0.50 (0.95) (-5.5 mmol/mol) vs -0.06 (0.80) (-0.7 mmol/mol) for ages 13 to 17 (P = .056). Diabetes-related QoL increased by 6.5 and 1.3 points for IRT and CC, respectively (P = .062). Three months after intervention cessation, %HbA1c changed minimally among treated children aged 8 to 12 but increased by 0.22 (0.89) (2.4 mmol/mol) among those aged 13 to 17. IRT substantially affected diabetes metrics and improved QoL among pediatric patients with T1D. Adolescents experienced a stronger treatment effect, but had difficulty in sustaining improved control after intervention cessation. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Item Response Theory. Research Report. ETS RR-13-28. ETS R&D Scientific and Policy Contributions Series. ETS SPC-13-05

ERIC Educational Resources Information Center

Carlson, James E.; von Davier, Matthias

2013-01-01

Few would doubt that ETS researchers have contributed more to the general topic of item response theory (IRT) than individuals from any other institution. In this report, we briefly review most of those contributions, dividing them into sections by decades of publication, beginning with early work by Fred Lord and Bert Green in the 1950s and…

Electronic signatures of dimerization in IrTe2

NASA Astrophysics Data System (ADS)

Dai, Jixia; Wu, Weida; Oh, Yoon Seok; Cheong, S.-W.; Yang, J. J.

2014-03-01

Recently, the mysterious phase transition around Tc ~ 260 K in IrTe2 has been intensively studied. A structural supermodulation with q =1/5 was identified below Tc. A variety of microscopic mechanisms have been proposed to account for this transition, including charge-density wave due to Fermi surface nesting, Te p-orbital driven structure instability, anionic depolymerization, ionic dimerization, and so on. However, there has not been an unified picture on the nature of this transition. To address this issue, we have performed low-temperature scanning tunneling microscopy and spectroscopy (STM/STS) experiments on IrTe2 and IrTe2-xSex. Our STM data clearly shows a strong bias dependence in both topography and local density of states (STS) maps. High resolution spectroscopic data further confirms the stripe-like electronic states modulation, which provides insight to the ionic dimerization revealed by X-ray diffraction.

Investigating Robustness of Item Response Theory Proficiency Estimators to Atypical Response Behaviors under Two-Stage Multistage Testing. ETS GRE® Board Research Report. ETS GRE®-16-03. ETS Research Report No. RR-16-22

ERIC Educational Resources Information Center

Kim, Sooyeon; Moses, Tim

2016-01-01

The purpose of this study is to evaluate the extent to which item response theory (IRT) proficiency estimation methods are robust to the presence of aberrant responses under the "GRE"® General Test multistage adaptive testing (MST) design. To that end, a wide range of atypical response behaviors affecting as much as 10% of the test items…

Pancreatic cellular injury after cardiac surgery with cardiopulmonary bypass: frequency, time course and risk factors.

PubMed

Nys, Monique; Venneman, Ingrid; Deby-Dupont, Ginette; Preiser, Jean-Charles; Vanbelle, Sophie; Albert, Adelin; Camus, Gérard; Damas, Pierre; Larbuisson, Robert; Lamy, Maurice

2007-05-01

Although often clinically silent, pancreatic cellular injury (PCI) is relatively frequent after cardiac surgery with cardiopulmonary bypass; and its etiology and time course are largely unknown. We defined PCI as the simultaneous presence of abnormal values of pancreatic isoamylase and immunoreactive trypsin (IRT). The frequency and time evolution of PCI were assessed in this condition using assays for specific exocrine pancreatic enzymes. Correlations with inflammatory markers were searched for preoperative risk factors. One hundred ninety-three patients submitted to cardiac surgery were enrolled prospectively. Blood IRT, amylase, pancreatic isoamylase, lipase, and markers of inflammation (alpha1-protease inhibitor, alpha2-macroglobulin, myeloperoxidase) were measured preoperatively and postoperatively until day 8. The postoperative increase in plasma levels of pancreatic enzymes and urinary IRT was biphasic in all patients: early after surgery and later (from day 4 to 8 after surgery). One hundred thirty-three patients (69%) experienced PCI, with mean IRT, isoamylase, and alpha1-protease inhibitor values higher for each sample than that in patients without PCI. By multiple regression analysis, we found preoperative values of plasma IRT >or=40 ng/mL, amylase >or=42 IU/mL, and pancreatic isoamylase >or=20 IU/L associated with a higher incidence of postsurgery PCI (P < 0.005). In the PCI patients, a significant correlation was found between the 4 pancreatic enzymes and urinary IRT, total calcium, myeloperoxidase, alpha1-protease inhibitor, and alpha2-macroglobulin. These data support a high prevalence of postoperative PCI after cardiac surgery with cardiopulmonary bypass, typically biphasic and clinically silent, especially when pancreatic enzymes were elevated preoperatively.

Differences of Cd uptake and expression of OAS and IRT genes in two varieties of ryegrasses.

PubMed

Chi, Sunlin; Qin, Yuli; Xu, Weihong; Chai, Yourong; Feng, Deyu; Li, Yanhua; Li, Tao; Yang, Mei; He, Zhangmi

2018-06-16

Pot experiment was conducted to study the difference of cadmium uptake and OAS and IRT genes' expression between the two ryegrass varieties under cadmium stress. The results showed that with the increase of cadmium levels, the dry weights of roots of the two ryegrass varieties, and the dry weights of shoots and plants of Abbott first increased and then decreased. When exposed to 75 mg kg -1 Cd, the dry weights of shoot and plant of Abbott reached the maximum, which increased by 11.13 and 10.67% compared with the control. At 75 mg kg -1 Cd, cadmium concentrations in shoot of the two ryegrass varieties were higher than the critical value of Cd hyperaccumulator (100 mg kg -1 ), 111.19 mg kg -1 (Bond), and 133.69 mg kg -1 (Abbott), respectively. The OAS gene expression in the leaves of the two ryegrass varieties showed a unimodal curve, which was up to the highest at the cadmium level of 150 mg kg -1 , but fell back at high cadmium levels of 300 and 600 mg kg -1 . The OAS gene expression in Bond and Abbott roots showed a bimodal curve. The OAS gene expression in Bond root and Abbott stem mainly showed a unimodal curve. The expression of IRT genes family in the leaves of ryegrass varieties was basically in line with the characteristics of unimodal curve, which was up to the highest at cadmium level of 75 or 150 mg kg -1 , respectively. The IRT expression in the ryegrass stems showed characteristics of bimodal and unimodal curves, while that in the roots was mainly unimodal. The expression of OAS and IRT genes was higher in Bond than that in Abbott due to genotype difference between the two varieties. The expression of OAS and IRT was greater in leaves than that in roots and stems. Ryegrass tolerance to cadmium can be increased by increasing the expression of OAS and IRT genes in roots and stems, and transfer of cadmium from roots and stems to the leaves can be enhanced by increasing expression OAS and IRT in leaves.

Ice-Accretion Test Results for Three Large-Scale Swept-Wing Models in the NASA Icing Research Tunnel

NASA Technical Reports Server (NTRS)

Broeren, Andy P.; Potapczuk, Mark G.; Lee, Sam; Malone, Adam M.; Paul, Benard P., Jr.; Woodard, Brian S.

2016-01-01

Icing simulation tools and computational fluid dynamics codes are reaching levels of maturity such that they are being proposed by manufacturers for use in certification of aircraft for flight in icing conditions with increasingly less reliance on natural-icing flight testing and icing-wind-tunnel testing. Sufficient high-quality data to evaluate the performance of these tools is not currently available. The objective of this work was to generate a database of ice-accretion geometry that can be used for development and validation of icing simulation tools as well as for aerodynamic testing. Three large-scale swept wing models were built and tested at the NASA Glenn Icing Research Tunnel (IRT). The models represented the Inboard (20% semispan), Midspan (64% semispan) and Outboard stations (83% semispan) of a wing based upon a 65% scale version of the Common Research Model (CRM). The IRT models utilized a hybrid design that maintained the full-scale leading-edge geometry with a truncated afterbody and flap. The models were instrumented with surface pressure taps in order to acquire sufficient aerodynamic data to verify the hybrid model design capability to simulate the full-scale wing section. A series of ice-accretion tests were conducted over a range of total temperatures from -23.8 deg C to -1.4 deg C with all other conditions held constant. The results showed the changing ice-accretion morphology from rime ice at the colder temperatures to highly 3-D scallop ice in the range of -11.2 deg C to -6.3 deg C. Warmer temperatures generated highly 3-D ice accretion with glaze ice characteristics. The results indicated that the general scallop ice morphology was similar for all three models. Icing results were documented for limited parametric variations in angle of attack, drop size and cloud liquid-water content (LWC). The effect of velocity on ice accretion was documented for the Midspan and Outboard models for a limited number of test cases. The data suggest that there are morphological characteristics of glaze and scallop ice accretion on these swept-wing models that are dependent upon the velocity. This work has resulted in a large database of ice-accretion geometry on large-scale, swept-wing models.

Ice-Accretion Test Results for Three Large-Scale Swept-Wing Models in the NASA Icing Research Tunnel

NASA Technical Reports Server (NTRS)

Broeren, Andy P.; Potapczuk, Mark G.; Lee, Sam; Malone, Adam M.; Paul, Bernard P., Jr.; Woodard, Brian S.

2016-01-01

Icing simulation tools and computational fluid dynamics codes are reaching levels of maturity such that they are being proposed by manufacturers for use in certification of aircraft for flight in icing conditions with increasingly less reliance on natural-icing flight testing and icing-wind-tunnel testing. Sufficient high-quality data to evaluate the performance of these tools is not currently available. The objective of this work was to generate a database of ice-accretion geometry that can be used for development and validation of icing simulation tools as well as for aerodynamic testing. Three large-scale swept wing models were built and tested at the NASA Glenn Icing Research Tunnel (IRT). The models represented the Inboard (20 percent semispan), Midspan (64 percent semispan) and Outboard stations (83 percent semispan) of a wing based upon a 65 percent scale version of the Common Research Model (CRM). The IRT models utilized a hybrid design that maintained the full-scale leading-edge geometry with a truncated afterbody and flap. The models were instrumented with surface pressure taps in order to acquire sufficient aerodynamic data to verify the hybrid model design capability to simulate the full-scale wing section. A series of ice-accretion tests were conducted over a range of total temperatures from -23.8 to -1.4 C with all other conditions held constant. The results showed the changing ice-accretion morphology from rime ice at the colder temperatures to highly 3-D scallop ice in the range of -11.2 to -6.3 C. Warmer temperatures generated highly 3-D ice accretion with glaze ice characteristics. The results indicated that the general scallop ice morphology was similar for all three models. Icing results were documented for limited parametric variations in angle of attack, drop size and cloud liquid-water content (LWC). The effect of velocity on ice accretion was documented for the Midspan and Outboard models for a limited number of test cases. The data suggest that there are morphological characteristics of glaze and scallop ice accretion on these swept-wing models that are dependent upon the velocity. This work has resulted in a large database of ice-accretion geometry on large-scale, swept-wing models.

IRT Item Parameter Scaling for Developing New Item Pools

ERIC Educational Resources Information Center

Kang, Hyeon-Ah; Lu, Ying; Chang, Hua-Hua

2017-01-01

Increasing use of item pools in large-scale educational assessments calls for an appropriate scaling procedure to achieve a common metric among field-tested items. The present study examines scaling procedures for developing a new item pool under a spiraled block linking design. The three scaling procedures are considered: (a) concurrent…

Designing P-Optimal Item Pools in Computerized Adaptive Tests with Polytomous Items

ERIC Educational Resources Information Center

Zhou, Xuechun

2012-01-01

Current CAT applications consist of predominantly dichotomous items, and CATs with polytomously scored items are limited. To ascertain the best approach to polytomous CAT, a significant amount of research has been conducted on item selection, ability estimation, and impact of termination rules based on polytomous IRT models. Few studies…

Item Response Theory Equating Using Bayesian Informative Priors.

ERIC Educational Resources Information Center

de la Torre, Jimmy; Patz, Richard J.

This paper seeks to extend the application of Markov chain Monte Carlo (MCMC) methods in item response theory (IRT) to include the estimation of equating relationships along with the estimation of test item parameters. A method is proposed that incorporates estimation of the equating relationship in the item calibration phase. Item parameters from…

The Asymptotic Distribution of Ability Estimates: Beyond Dichotomous Items and Unidimensional IRT Models

ERIC Educational Resources Information Center

Sinharay, Sandip

2015-01-01

The maximum likelihood estimate (MLE) of the ability parameter of an item response theory model with known item parameters was proved to be asymptotically normally distributed under a set of regularity conditions for tests involving dichotomous items and a unidimensional ability parameter (Klauer, 1990; Lord, 1983). This article first considers…

Comparison of LEWICE 1.6 and LEWICE/NS with IRT experimental data from modern air foil tests

DOT National Transportation Integrated Search

1998-01-01

A research project is underway at NASA Lewis to produce a computer code which can accurately predict ice growth under any meteorological conditions for any aircraft surface. The most recent release of this code is LEWICE 1.6. This code is modular in ...

Simultaneous Estimation of Overall and Domain Abilities: A Higher-Order IRT Model Approach

ERIC Educational Resources Information Center

de la Torre, Jimmy; Song, Hao

2009-01-01

Assessments consisting of different domains (e.g., content areas, objectives) are typically multidimensional in nature but are commonly assumed to be unidimensional for estimation purposes. The different domains of these assessments are further treated as multi-unidimensional tests for the purpose of obtaining diagnostic information. However, when…

Estimating True Student Growth Percentile Distributions Using Latent Regression Multidimensional IRT Models

ERIC Educational Resources Information Center

Lockwood, J. R.; Castellano, Katherine E.

2017-01-01

Student Growth Percentiles (SGPs) increasingly are being used in the United States for inferences about student achievement growth and educator effectiveness. Emerging research has indicated that SGPs estimated from observed test scores have large measurement errors. As such, little is known about "true" SGPs, which are defined in terms…

A Nonparametric Approach to Estimate Classification Accuracy and Consistency

ERIC Educational Resources Information Center

Lathrop, Quinn N.; Cheng, Ying

2014-01-01

When cut scores for classifications occur on the total score scale, popular methods for estimating classification accuracy (CA) and classification consistency (CC) require assumptions about a parametric form of the test scores or about a parametric response model, such as item response theory (IRT). This article develops an approach to estimate CA…

Calibration and Validation of the Dutch-Flemish PROMIS Pain Interference Item Bank in Patients with Chronic Pain

PubMed Central

Crins, Martine H. P.; Roorda, Leo D.; Smits, Niels; de Vet, Henrica C. W.; Westhovens, Rene; Cella, David; Cook, Karon F.; Revicki, Dennis; van Leeuwen, Jaap; Boers, Maarten; Dekker, Joost; Terwee, Caroline B.

2015-01-01

The Dutch-Flemish PROMIS Group translated the adult PROMIS Pain Interference item bank into Dutch-Flemish. The aims of the current study were to calibrate the parameters of these items using an item response theory (IRT) model, to evaluate the cross-cultural validity of the Dutch-Flemish translations compared to the original English items, and to evaluate their reliability and construct validity. The 40 items in the bank were completed by 1085 Dutch chronic pain patients. Before calibrating the items, IRT model assumptions were evaluated using confirmatory factor analysis (CFA). Items were calibrated using the graded response model (GRM), an IRT model appropriate for items with more than two response options. To evaluate cross-cultural validity, differential item functioning (DIF) for language (Dutch vs. English) was examined. Reliability was evaluated based on standard errors and Cronbach’s alpha. To evaluate construct validity correlations with scores on legacy instruments (e.g., the Disabilities of the Arm, Shoulder and Hand Questionnaire) were calculated. Unidimensionality of the Dutch-Flemish PROMIS Pain Interference item bank was supported by CFA tests of model fit (CFI = 0.986, TLI = 0.986). Furthermore, the data fit the GRM and showed good coverage across the pain interference continuum (threshold-parameters range: -3.04 to 3.44). The Dutch-Flemish PROMIS Pain Interference item bank has good cross-cultural validity (only two out of 40 items showing DIF), good reliability (Cronbach’s alpha = 0.98), and good construct validity (Pearson correlations between 0.62 and 0.75). A computer adaptive test (CAT) and Dutch-Flemish PROMIS short forms of the Dutch-Flemish PROMIS Pain Interference item bank can now be developed. PMID:26214178

Cognitive Trajectory Changes Over 20 Years Before Dementia Diagnosis: A Large Cohort Study.

PubMed

Li, Ge; Larson, Eric B; Shofer, Jane B; Crane, Paul K; Gibbons, Laura E; McCormick, Wayne; Bowen, James D; Thompson, Mary Lou

2017-12-01

Longitudinal studies have shown an increase in cognitive decline many years before clinical diagnosis of dementia. We sought to estimate changes, relative to "normal" aging, in the trajectory of scores on a global cognitive function test-the Cognitive Abilities Screening Instrument (CASI). A prospective cohort study. Community-dwelling members of a U.S. health maintenance organization. Individuals aged 65 and older who had no dementia diagnosis at baseline and had at least two visits with valid CASI test score (N = 4,315). Average longitudinal trajectories, including changes in trajectory before clinical diagnosis in those who would be diagnosed with dementia, were estimated for CASI item response theory (IRT) scores. The impact of sex, education level, and APOE genotype on cognitive trajectories was assessed. Increased cognitive decline relative to "normal" aging was evident in CASI IRT at least 10 years before clinical diagnosis. Male gender, lower education, and presence of ≥1 APOE ε4 alleles were associated with lower average IRT scores. In those who would be diagnosed with dementia, a trajectory change point was estimated at an average of 3.1 years (95% confidence interval 3.0-3.2) before clinical diagnosis, after which cognitive decline appeared to accelerate. The change point did not differ by sex, education level, or APOE ε4 genotype. There were subtle differences in trajectory slopes by sex and APOE ε4 genotype, but not by education. Decline in average global cognitive function was evident at least 10 years before clinical diagnosis of dementia. The decline accelerated about 3 years before clinical diagnosis. © 2017, Copyright the Authors Journal compilation © 2017, The American Geriatrics Society.

[Development of patient-reported outcome scale for myasthenia gravis: a psychometric test].

PubMed

Chen, Xin-lin; Liu, Feng-bin; Guo, Li; Liu, Xiao-bin

2010-02-01

To investigate the scientificity of patient-reported outcome (PRO) scale for myasthenia gravis (MG), which was used to evaluate the clinical effects of traditional Chinese and Western medicine treatment on MG patients. Psychometric performance of the MG-PRO scale was also expected to be evaluated in this study. A total of 100 MG patients and 100 healthy people were face-to-face interviewed by well-trained investigators, and the data of MG-PRO scale were collected. The classical theory test (CTT) and item response theory (IRT) methods were used to analyze the psychometric performance such as validity, reliability, person separation index (PSI) and differential item functioning (DIF) in the MG-PRO scale. The results of CTT analysis showed that the split-half reliabilities of the MG-PRO scale and each dimension were greater than 0.7. In the analysis of internal consistency of each dimension, the Cronbach's alpha was greater than 0.8. Each facet had greater correlation with its dimension than the other dimensions. Four principal components were extracted by exploratory factor analysis, which represented all dimensions of the scale, and the cumulative variance was 55.54%. The scores of each of the 8 facets between MG patients and healthy people were different (P<0.01). The results of IRT showed that the PSI of each model was greater than 0.8, and all items did not have uniform DIF and non-uniform DIF. The MG-PRO scale reflects the definition and connotation of quality of life and contains special issues of MG patients as well, and shows good reliability (split-half reliability, Cronbach's alpha), validity (content validity, construct validity, discriminate validity) from the results of CTT, and good psychometric performance from the results of IRT.

Calibration and Validation of the Dutch-Flemish PROMIS Pain Interference Item Bank in Patients with Chronic Pain.

PubMed

Crins, Martine H P; Roorda, Leo D; Smits, Niels; de Vet, Henrica C W; Westhovens, Rene; Cella, David; Cook, Karon F; Revicki, Dennis; van Leeuwen, Jaap; Boers, Maarten; Dekker, Joost; Terwee, Caroline B

2015-01-01

The Dutch-Flemish PROMIS Group translated the adult PROMIS Pain Interference item bank into Dutch-Flemish. The aims of the current study were to calibrate the parameters of these items using an item response theory (IRT) model, to evaluate the cross-cultural validity of the Dutch-Flemish translations compared to the original English items, and to evaluate their reliability and construct validity. The 40 items in the bank were completed by 1085 Dutch chronic pain patients. Before calibrating the items, IRT model assumptions were evaluated using confirmatory factor analysis (CFA). Items were calibrated using the graded response model (GRM), an IRT model appropriate for items with more than two response options. To evaluate cross-cultural validity, differential item functioning (DIF) for language (Dutch vs. English) was examined. Reliability was evaluated based on standard errors and Cronbach's alpha. To evaluate construct validity correlations with scores on legacy instruments (e.g., the Disabilities of the Arm, Shoulder and Hand Questionnaire) were calculated. Unidimensionality of the Dutch-Flemish PROMIS Pain Interference item bank was supported by CFA tests of model fit (CFI = 0.986, TLI = 0.986). Furthermore, the data fit the GRM and showed good coverage across the pain interference continuum (threshold-parameters range: -3.04 to 3.44). The Dutch-Flemish PROMIS Pain Interference item bank has good cross-cultural validity (only two out of 40 items showing DIF), good reliability (Cronbach's alpha = 0.98), and good construct validity (Pearson correlations between 0.62 and 0.75). A computer adaptive test (CAT) and Dutch-Flemish PROMIS short forms of the Dutch-Flemish PROMIS Pain Interference item bank can now be developed.

Ultralow dose dentomaxillofacial CT imaging and iterative reconstruction techniques: variability of Hounsfield units and contrast-to-noise ratio

PubMed Central

Bischel, Alexander; Stratis, Andreas; Kakar, Apoorv; Bosmans, Hilde; Jacobs, Reinhilde; Gassner, Eva-Maria; Puelacher, Wolfgang; Pauwels, Ruben

2016-01-01

Objective: The aim of this study was to evaluate whether application of ultralow dose protocols and iterative reconstruction technology (IRT) influence quantitative Hounsfield units (HUs) and contrast-to-noise ratio (CNR) in dentomaxillofacial CT imaging. Methods: A phantom with inserts of five types of materials was scanned using protocols for (a) a clinical reference for navigated surgery (CT dose index volume 36.58 mGy), (b) low-dose sinus imaging (18.28 mGy) and (c) four ultralow dose imaging (4.14, 2.63, 0.99 and 0.53 mGy). All images were reconstructed using: (i) filtered back projection (FBP); (ii) IRT: adaptive statistical iterative reconstruction-50 (ASIR-50), ASIR-100 and model-based iterative reconstruction (MBIR); and (iii) standard (std) and bone kernel. Mean HU, CNR and average HU error after recalibration were determined. Each combination of protocols was compared using Friedman analysis of variance, followed by Dunn's multiple comparison test. Results: Pearson's sample correlation coefficients were all >0.99. Ultralow dose protocols using FBP showed errors of up to 273 HU. Std kernels had less HU variability than bone kernels. MBIR reduced the error value for the lowest dose protocol to 138 HU and retained the highest relative CNR. ASIR could not demonstrate significant advantages over FBP. Conclusions: Considering a potential dose reduction as low as 1.5% of a std protocol, ultralow dose protocols and IRT should be further tested for clinical dentomaxillofacial CT imaging. Advances in knowledge: HU as a surrogate for bone density may vary significantly in CT ultralow dose imaging. However, use of std kernels and MBIR technology reduce HU error values and may retain the highest CNR. PMID:26859336

High systemic and testicular thermolytic efficiency during heat tolerance test reflects better semen quality in rams of tropical breeds

NASA Astrophysics Data System (ADS)

Kahwage, Priscila Reis; Esteves, Sérgio Novita; Jacinto, Manuel Antônio Chagas; Junior, Waldomiro Barioni; Pezzopane, José Ricardo Macedo; de Andrade Pantoja, Messy Hannear; Bosi, Cristian; Miguel, Maria Carolina Villani; Mahlmeister, Kaue; Garcia, Alexandre Rossetto

2017-10-01

This study aimed to assess the capacity of Morada Nova (MN) and Santa Inês (SIN) rams to maintain body and testicular homeothermy under thermal challenge. For 5 days in the summer, 16 males (SIN = 7 and MN = 9) underwent a heat tolerance test, i.e., period 1—animals maintained in the shade (11 to 12 h); period 2—animals exposed to sunlight (12 to 13 h); and period 3—animals returned to the shade (13 to 14 h). The respiratory rate, heart rate, rectal temperature, and infrared surface temperatures (IRT) of the trunk, back, eyeball, and testicles were assessed in each period. The index of capacity of tolerance to insolation (ICTI), which indicates the animals' level of adaptability, was calculated for each animal. Semen quality and testicular parenchyma integrity were assessed before and after the thermal challenge. Statistical analyses were performed at 5% significance. In period 1, the variables had baseline values for both genotypes. In period 2, the variables involved in thermolysis significantly increased ( P < 0.05), which matches a thermal discomfort situation. In period 3, the variables returned to baseline values and some values were lower than those in period 1. Semen quality and testicular parenchyma integrity suffered no negative effects with the thermal challenge. IRT ocular and IRT testicular were positively correlated ( P < 0.05). It is concluded that MN and SIN rams had efficient thermolytic mechanisms that favor preserving gonadal functionality. The animals were considered resilient to a thermal challenge. In addition, infrared thermography was an efficient tool to verify body and testicular thermoregulation.

Measurement Equivalence in ADL and IADL Difficulty Across International Surveys of Aging: Findings From the HRS, SHARE, and ELSA

PubMed Central

Kasper, Judith D.; Brandt, Jason; Pezzin, Liliana E.

2012-01-01

Objective. To examine the measurement equivalence of items on disability across three international surveys of aging. Method. Data for persons aged 65 and older were drawn from the Health and Retirement Survey (HRS, n = 10,905), English Longitudinal Study of Aging (ELSA, n = 5,437), and Survey of Health, Ageing and Retirement in Europe (SHARE, n = 13,408). Differential item functioning (DIF) was assessed using item response theory (IRT) methods for activities of daily living (ADL) and instrumental activities of daily living (IADL) items. Results. HRS and SHARE exhibited measurement equivalence, but 6 of 11 items in ELSA demonstrated meaningful DIF. At the scale level, this item-level DIF affected scores reflecting greater disability. IRT methods also spread out score distributions and shifted scores higher (toward greater disability). Results for mean disability differences by demographic characteristics, using original and DIF-adjusted scores, were the same overall but differed for some subgroup comparisons involving ELSA. Discussion. Testing and adjusting for DIF is one means of minimizing measurement error in cross-national survey comparisons. IRT methods were used to evaluate potential measurement bias in disability comparisons across three international surveys of aging. The analysis also suggested DIF was mitigated for scales including both ADL and IADL and that summary indexes (counts of limitations) likely underestimate mean disability in these international populations. PMID:22156662

Evaluation of a preliminary physical function item bank supported the expected advantages of the Patient-Reported Outcomes Measurement Information System (PROMIS).

PubMed

Rose, M; Bjorner, J B; Becker, J; Fries, J F; Ware, J E

2008-01-01

The Patient-Reported Outcomes Measurement Information System (PROMIS) was initiated to improve precision, reduce respondent burden, and enhance the comparability of health outcomes measures. We used item response theory (IRT) to construct and evaluate a preliminary item bank for physical function assuming four subdomains. Data from seven samples (N=17,726) using 136 items from nine questionnaires were evaluated. A generalized partial credit model was used to estimate item parameters, which were normed to a mean of 50 (SD=10) in the US population. Item bank properties were evaluated through Computerized Adaptive Test (CAT) simulations. IRT requirements were fulfilled by 70 items covering activities of daily living, lower extremity, and central body functions. The original item context partly affected parameter stability. Items on upper body function, and need for aid or devices did not fit the IRT model. In simulations, a 10-item CAT eliminated floor and decreased ceiling effects, achieving a small standard error (< 2.2) across scores from 20 to 50 (reliability >0.95 for a representative US sample). This precision was not achieved over a similar range by any comparable fixed length item sets. The methods of the PROMIS project are likely to substantially improve measures of physical function and to increase the efficiency of their administration using CAT.

Item response theory analysis of the Lichtenberg Financial Decision Screening Scale.

PubMed

Teresi, Jeanne A; Ocepek-Welikson, Katja; Lichtenberg, Peter A

2017-01-01

The focus of these analyses was to examine the psychometric properties of the Lichtenberg Financial Decision Screening Scale (LFDSS). The purpose of the screen was to evaluate the decisional abilities and vulnerability to exploitation of older adults. Adults aged 60 and over were interviewed by social, legal, financial, or health services professionals who underwent in-person training on the administration and scoring of the scale. Professionals provided a rating of the decision-making abilities of the older adult. The analytic sample included 213 individuals with an average age of 76.9 (SD = 10.1). The majority (57%) were female. Data were analyzed using item response theory (IRT) methodology. The results supported the unidimensionality of the item set. Several IRT models were tested. Ten ordinal and binary items evidenced a slightly higher reliability estimate (0.85) than other versions and better coverage in terms of the range of reliable measurement across the continuum of financial incapacity.

An analysis of the DuPage County Regional Office of Education physics exam

NASA Astrophysics Data System (ADS)

Muehsler, Hans

In 2009, the DuPage County Regional Office of Education (ROE) tasked volunteer physics teachers with creating a basic skills physics exam reflecting what the participants valued and shared in common across curricula. Mechanics, electricity & magnetism (E&M), and wave phenomena emerged as the primary constructs. The resulting exam was intended for first-exposure physics students. The most recently completed version was psychometrically assessed for unidimensionality within the constructs using a robust WLS structural equation model and for reliability. An item analysis using a 3-PL IRT model was performed on the mechanics items and a 2-PL IRT model was performed on the E&M and waves items; a distractor analysis was also performed on all items. Lastly, differential item functioning (DIF) and differential test functioning (DTF) analyses, using the Mantel-Haenszel procedure, were performed using gender, ethnicity, year in school, ELL, physics level, and math level as groupings.

A Longitudinal Item Response Theory Model to Characterize Cognition Over Time in Elderly Subjects

PubMed Central

Bornkamp, Björn; Krahnke, Tillmann; Mielke, Johanna; Monsch, Andreas; Quarg, Peter

2017-01-01

For drug development in neurodegenerative diseases such as Alzheimer's disease, it is important to understand which cognitive domains carry the most information on the earliest signs of cognitive decline, and which subject characteristics are associated with a faster decline. A longitudinal Item Response Theory (IRT) model was developed for the Basel Study on the Elderly, in which the Consortium to Establish a Registry for Alzheimer's Disease – Neuropsychological Assessment Battery (with additions) and the California Verbal Learning Test were measured on 1,750 elderly subjects for up to 13.9 years. The model jointly captured the multifaceted nature of cognition and its longitudinal trajectory. The word list learning and delayed recall tasks carried the most information. Greater age at baseline, fewer years of education, and positive APOEɛ4 carrier status were associated with a faster cognitive decline. Longitudinal IRT modeling is a powerful approach for progressive diseases with multifaceted endpoints. PMID:28643388

A new item response theory model to adjust data allowing examinee choice

PubMed Central

Costa, Marcelo Azevedo; Braga Oliveira, Rivert Paulo

2018-01-01

In a typical questionnaire testing situation, examinees are not allowed to choose which items they answer because of a technical issue in obtaining satisfactory statistical estimates of examinee ability and item difficulty. This paper introduces a new item response theory (IRT) model that incorporates information from a novel representation of questionnaire data using network analysis. Three scenarios in which examinees select a subset of items were simulated. In the first scenario, the assumptions required to apply the standard Rasch model are met, thus establishing a reference for parameter accuracy. The second and third scenarios include five increasing levels of violating those assumptions. The results show substantial improvements over the standard model in item parameter recovery. Furthermore, the accuracy was closer to the reference in almost every evaluated scenario. To the best of our knowledge, this is the first proposal to obtain satisfactory IRT statistical estimates in the last two scenarios. PMID:29389996

Item response theory and factor analysis as a mean to characterize occurrence of response shift in a longitudinal quality of life study in breast cancer patients

PubMed Central

2014-01-01

Background The occurrence of response shift (RS) in longitudinal health-related quality of life (HRQoL) studies, reflecting patient adaptation to disease, has already been demonstrated. Several methods have been developed to detect the three different types of response shift (RS), i.e. recalibration RS, 2) reprioritization RS, and 3) reconceptualization RS. We investigated two complementary methods that characterize the occurrence of RS: factor analysis, comprising Principal Component Analysis (PCA) and Multiple Correspondence Analysis (MCA), and a method of Item Response Theory (IRT). Methods Breast cancer patients (n = 381) completed the EORTC QLQ-C30 and EORTC QLQ-BR23 questionnaires at baseline, immediately following surgery, and three and six months after surgery, according to the “then-test/post-test” design. Recalibration was explored using MCA and a model of IRT, called the Linear Logistic Model with Relaxed Assumptions (LLRA) using the then-test method. Principal Component Analysis (PCA) was used to explore reconceptualization and reprioritization. Results MCA highlighted the main profiles of recalibration: patients with high HRQoL level report a slightly worse HRQoL level retrospectively and vice versa. The LLRA model indicated a downward or upward recalibration for each dimension. At six months, the recalibration effect was statistically significant for 11/22 dimensions of the QLQ-C30 and BR23 according to the LLRA model (p ≤ 0.001). Regarding the QLQ-C30, PCA indicated a reprioritization of symptom scales and reconceptualization via an increased correlation between functional scales. Conclusions Our findings demonstrate the usefulness of these analyses in characterizing the occurrence of RS. MCA and IRT model had convergent results with then-test method to characterize recalibration component of RS. PCA is an indirect method in investigating the reprioritization and reconceptualization components of RS. PMID:24606836

Sci—Thur AM: YIS - 03: irtGPUMCD: a new GPU-calculated dosimetry code for {sup 177}Lu-octreotate radionuclide therapy of neuroendocrine tumors

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

Montégiani, Jean-François; Gaudin, Émilie; Després, Philippe

2014-08-15

In peptide receptor radionuclide therapy (PRRT), huge inter-patient variability in absorbed radiation doses per administered activity mandates the utilization of individualized dosimetry to evaluate therapeutic efficacy and toxicity. We created a reliable GPU-calculated dosimetry code (irtGPUMCD) and assessed {sup 177}Lu-octreotate renal dosimetry in eight patients (4 cycles of approximately 7.4 GBq). irtGPUMCD was derived from a brachytherapy dosimetry code (bGPUMCD), which was adapted to {sup 177}Lu PRRT dosimetry. Serial quantitative single-photon emission computed tomography (SPECT) images were obtained from three SPECT/CT acquisitions performed at 4, 24 and 72 hours after {sup 177}Lu-octreotate administration, and registered with non-rigid deformation of CTmore » volumes, to obtain {sup 177}Lu-octreotate 4D quantitative biodistribution. Local energy deposition from the β disintegrations was assumed. Using Monte Carlo gamma photon transportation, irtGPUMCD computed dose rate at each time point. Average kidney absorbed dose was obtained from 1-cm{sup 3} VOI dose rate samples on each cortex, subjected to a biexponential curve fit. Integration of the latter time-dose rate curve yielded the renal absorbed dose. The mean renal dose per administered activity was 0.48 ± 0.13 Gy/GBq (range: 0.30–0.71 Gy/GBq). Comparison to another PRRT dosimetry code (VRAK: Voxelized Registration and Kinetics) showed fair accordance with irtGPUMCD (11.4 ± 6.8 %, range: 3.3–26.2%). These results suggest the possibility to use the irtGPUMCD code in order to personalize administered activity in PRRT. This could allow improving clinical outcomes by maximizing per-cycle tumor doses, without exceeding the tolerable renal dose.« less

Monitoring intrahepatic cholestasis of pregnancy using the fetal myocardial performance index: a cohort study.

PubMed

Henry, A; Welsh, A W

2015-11-01

To investigate use of the fetal myocardial performance index (MPI) in assessing intrahepatic cholestasis of pregnancy (ICP). This was a cohort study including cross-sectional and longitudinal data from 31 women with ICP recruited from June 2012 to March 2014. Fetal left, right and delta MPI (LMPI, RMPI and DMPI), and routine measures of fetal growth and wellbeing, were obtained at each ultrasound examination. Results were evaluated with respect to gestational age (GA)-adjusted reference intervals, level of maternal serum bile acid (SBA) and fetal outcome. Lower SBA (≥ 7.5 and < 40 μmol/L) and high SBA (≥ 40 μmol/L) subgroups of cases were defined for the analysis. A total of 51 ultrasound examinations were performed in 33 fetuses. The mean LMPI, and means of its isovolumetric relaxation time (IRT) and isovolumetric contraction time (ICT) components were significantly higher in all subgroups of cases of ICP relative to the normal reference mean. Considering only the first examination in each case of ICP, IRT was significantly more prolonged in the high SBA group (n = 10) in comparison to the lower SBA group (n = 23) (52.7 ± 8.0 ms vs 47.3 ± 4.8 ms, P = 0.02), and both IRT (r = 0.538, P = 0.001) and LMPI (r = 0.367, P = 0.036) were significantly correlated with SBA concentration. The proportion of high SBA cases with LMPI, RMPI or DMPI > 2 SD above the GA-adjusted reference mean was not significantly greater than for the lower SBA group. On analysis of all data from those cases with more than one examination, no significant correlation was found between SBA concentration and any of the MPI variables. LMPI values increase above the population GA-adjusted mean in cases of ICP, particularly amongst women with higher SBA. A significant correlation between IRT and LMPI at initial examination and increasing SBA concentration was found. A future multicenter prospective study may clarify the prognostic utility of MPI in ICP. Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.

Molecular Imaging and Therapy of Prostate Cancer

DTIC Science & Technology

2015-10-01

arsenic-based, IGF1R-targeted radiopharmaceuticals can allow for PET imaging, IRT, and monitoring the therapeutic response of PCa. Specific Aims: Aim 1: To...models with PET imaging. Aim 3: To monitor the efficacy of 76As-based IRT of PCa with multimodality imaging.

Model Selection Methods for Mixture Dichotomous IRT Models

ERIC Educational Resources Information Center

Li, Feiming; Cohen, Allan S.; Kim, Seock-Ho; Cho, Sun-Joo

2009-01-01

This study examines model selection indices for use with dichotomous mixture item response theory (IRT) models. Five indices are considered: Akaike's information coefficient (AIC), Bayesian information coefficient (BIC), deviance information coefficient (DIC), pseudo-Bayes factor (PsBF), and posterior predictive model checks (PPMC). The five…

A Zero- and K-Inflated Mixture Model for Health Questionnaire Data

PubMed Central

Finkelman, Matthew D.; Green, Jennifer Greif; Gruber, Michael J.; Zaslavsky, Alan M.

2011-01-01

In psychiatric assessment, Item Response Theory (IRT) is a popular tool to formalize the relation between the severity of a disorder and associated responses to questionnaire items. Practitioners of IRT sometimes make the assumption of normally distributed severities within a population; while convenient, this assumption is often violated when measuring psychiatric disorders. Specifically, there may be a sizable group of respondents whose answers place them at an extreme of the latent trait spectrum. In this article, a zero- and K-inflated mixture model is developed to account for the presence of such respondents. The model is fitted using an expectation-maximization (E-M) algorithm to estimate the percentage of the population at each end of the continuum, concurrently analyzing the remaining “graded component” via IRT. A method to perform factor analysis for only the graded component is introduced. In assessments of oppositional defiant disorder and conduct disorder, the zero- and K-inflated model exhibited better fit than the standard IRT model. PMID:21365673

How States Can Reduce the Dropout Rate for Undocumented Immigrant Youth: The Effects of In-State Resident Tuition Policies

PubMed Central

Potochnick, Stephanie

2016-01-01

As of December 2011, 13 states have adopted an in-state resident tuition (IRT) policy that provides in-state tuition to undocumented immigrants and several other states are considering similar legislation. While previous research focuses on how IRT policies affect college entry and attainment, this study examines the effect these policies have on high school dropout behavior. Using the Current Population Survey (CPS) and difference-in-difference models, this paper examines whether IRT policies reduce the likelihood of dropping out of high school for Mexican foreign-born non-citizens (FBNC), a proxy for undocumented youth. The policy is estimated to cause an eight percentage point reduction in the proportion that drops out of high school. The paper develops an integrated framework that combines human capital theory with segmented assimilation theory to provide insight into how IRT policies influence student motivation and educational attainment at the high school level. PMID:24576624

Ground and surface temperature variability for remote sensing of soil moisture in a heterogeneous landscape

USGS Publications Warehouse

Giraldo, M.A.; Bosch, D.; Madden, M.; Usery, L.; Finn, M.

2009-01-01

At the Little River Watershed (LRW) heterogeneous landscape near Tifton Georgia US an in situ network of stations operated by the US Department of Agriculture-Agriculture Research Service-Southeast Watershed Research Lab (USDA-ARS-SEWRL) was established in 2003 for the long term study of climatic and soil biophysical processes. To develop an accurate interpolation of the in situ readings that can be used to produce distributed representations of soil moisture (SM) and energy balances at the landscape scale for remote sensing studies, we studied (1) the temporal and spatial variations of ground temperature (GT) and infra red temperature (IRT) within 30 by 30 m plots around selected network stations; (2) the relationship between the readings from the eight 30 by 30 m plots and the point reading of the network stations for the variables SM, GT and IRT; and (3) the spatial and temporal variation of GT and IRT within agriculture landuses: grass, orchard, peanuts, cotton and bare soil in the surrounding landscape. The results showed high correlations between the station readings and the adjacent 30 by 30 m plot average value for SM; high seasonal independent variation in the GT and IRT behavior among the eight 30 by 30 m plots; and site specific, in-field homogeneity in each 30 by 30 m plot. We found statistical differences in the GT and IRT between the different landuses as well as high correlations between GT and IRT regardless of the landuse. Greater standard deviations for IRT than for GT (in the range of 2-4) were found within the 30 by 30 m, suggesting that when a single point reading for this variable is selected for the validation of either remote sensing data or water-energy models, errors may occur. The results confirmed that in this landscape homogeneous 30 by 30 m plots can be used as landscape spatial units for soil moisture and ground temperature studies. Under this landscape conditions small plots can account for local expressions of environmental processes, decreasing the errors and uncertainties in remote sensing estimates caused by landscape heterogeneity.

Inhibitor-resistant TEM- and OXA-1-producing Escherichia coli isolates resistant to amoxicillin-clavulanate are more clonal and possess lower virulence gene content than susceptible clinical isolates.

PubMed

Oteo, Jesús; González-López, Juan José; Ortega, Adriana; Quintero-Zárate, J Natalia; Bou, Germán; Cercenado, Emilia; Conejo, María Carmen; Martínez-Martínez, Luis; Navarro, Ferran; Oliver, Antonio; Bartolomé, Rosa M; Campos, José

2014-07-01

In a previous prospective multicenter study in Spain, we found that OXA-1 and inhibitor-resistant TEM (IRT) β-lactamases constitute the most common plasmid-borne mechanisms of genuine amoxicillin-clavulanate (AMC) resistance in Escherichia coli. In the present study, we investigated the population structure and virulence traits of clinical AMC-resistant E. coli strains expressing OXA-1 or IRT and compared these traits to those in a control group of clinical AMC-susceptible E. coli isolates. All OXA-1-producing (n = 67) and IRT-producing (n = 45) isolates were matched by geographical and temporal origin to the AMC-susceptible control set (n = 56). We performed multilocus sequence typing and phylogenetic group characterization for each isolate and then studied the isolates for the presence of 49 virulence factors (VFs) by PCR and sequencing. The most prevalent clone detected was distinct for each group: group C isolates of sequence type (ST) 88 (C/ST88) were the most common in OXA-1 producers, B2/ST131 isolates were the most common in IRT producers, and B2/ST73 isolates were the most common in AMC-susceptible isolates. The median numbers of isolates per ST were 3.72 in OXA-1 producers, 2.04 in IRT producers, and 1.69 in AMC-susceptible isolates; the proportions of STs represented by one unique isolate in each group were 19.4%, 31.1%, and 48.2%, respectively. The sum of all VFs detected, calculated as a virulence score, was significantly higher in AMC-susceptible isolates than OXA-1 and IRT producers (means, 12.5 versus 8.3 and 8.2, respectively). Our findings suggest that IRT- and OXA-1-producing E. coli isolates resistant to AMC have a different and less diverse population structure than AMC-susceptible clinical E. coli isolates. The AMC-susceptible population also contains more VFs than AMC-resistant isolates. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Examining the Impact of Drifted Polytomous Anchor Items on Test Characteristic Curve (TCC) Linking and IRT True Score Equating. Research Report. ETS RR-12-09

ERIC Educational Resources Information Center

Li, Yanmei

2012-01-01

In a common-item (anchor) equating design, the common items should be evaluated for item parameter drift. Drifted items are often removed. For a test that contains mostly dichotomous items and only a small number of polytomous items, removing some drifted polytomous anchor items may result in anchor sets that no longer resemble mini-versions of…

Thermal performance evaluation of the infrared telescope dewar subsystem

NASA Technical Reports Server (NTRS)

Urban, E. W.

1986-01-01

Thermal performance evaluations (TPE) were conducted with the superfluid helium dewar of the Infrared Telescope (IRT) experiment from November 1981 to August 1982. Test included measuring key operating parameters, simulating operations with an attached instrument cryostat and validating servicing, operating and safety procedures. Test activities and results are summarized. All objectives are satisfied except for those involving transfer of low pressure liquid helium (LHe) from a supply dewar into the dewar subsystem.

Tier One Performance Screen Initial Operational Test and Evaluation: 2012 Interim Report

DTIC Science & Technology

2013-12-01

are known to predict outcomes in work settings. Because the TAPAS uses item response theory (IRT) methods to construct and score items, it can be...Qualification Test (AFQT), to select new Soldiers. Although the AFQT is useful for selecting new Soldiers, other personal attributes are important to...to be and will continue to serve as a useful metric for selecting new Soldiers, other personal attributes, in particular non-cognitive attributes

An Item Response Theory (IRT) analysis of the Short Inventory of Problems-Alcohol and Drugs (SIP-AD) among non-treatment seeking men-who-have-sex-with-men: evidence for a shortened 10-item SIP-AD.

PubMed

Hagman, Brett T; Kuerbis, Alexis N; Morgenstern, Jon; Bux, Donald A; Parsons, Jeffrey T; Heidinger, Bram E

2009-11-01

The Short Inventory of Problems-Alcohol and Drugs (SIP-AD) is a 15-item measure that assesses concurrently negative consequences associated with alcohol and illicit drug use. Current psychometric evaluation has been limited to classical test theory (CTT) statistics, and it has not been validated among non-treatment seeking men-who-have-sex-with-men (MSM). Methods from Item Response Theory (IRT) can improve upon CTT by providing an in-depth analysis of how each item performs across the underlying latent trait that it is purported to measure. The present study examined the psychometric properties of the SIP-AD using methods from both IRT and CTT among a non-treatment seeking MSM sample (N=469). Participants were recruited from the New York City area and were asked to participate in a series of studies examining club drug use. Results indicated that five items on the SIP-AD demonstrated poor item misfit or significant differential item functioning (DIF) across race/ethnicity and HIV status. These five items were dropped and two-parameter IRT analyses were conducted on the remaining 10 items, which indicated a restricted range of item location parameters (-.15 to -.99) plotted at the lower end of the latent negative consequences severity continuum, and reasonably high discrimination parameters (1.30 to 2.22). Additional CTT statistics were compared between the original 15-item SIP-AD and the refined 10-item SIP-AD and suggest that the differences were negligible with the refined 10-item SIP-AD indicating a high degree of reliability and validity. Findings suggest the SIP-AD can be shortened to 10 items and appears to be a non-biased reliable and valid measure among non-treatment seeking MSM.

Estimating the Nominal Response Model under Nonnormal Conditions

ERIC Educational Resources Information Center

Preston, Kathleen Suzanne Johnson; Reise, Steven Paul

2014-01-01

The nominal response model (NRM), a much understudied polytomous item response theory (IRT) model, provides researchers the unique opportunity to evaluate within-item category distinctions. Polytomous IRT models, such as the NRM, are frequently applied to psychological assessments representing constructs that are unlikely to be normally…

An Instructional Module on Mokken Scale Analysis

ERIC Educational Resources Information Center

Wind, Stefanie A.

2017-01-01

Mokken scale analysis (MSA) is a probabilistic-nonparametric approach to item response theory (IRT) that can be used to evaluate fundamental measurement properties with less strict assumptions than parametric IRT models. This instructional module provides an introduction to MSA as a probabilistic-nonparametric framework in which to explore…

Comparing Three Estimation Methods for the Three-Parameter Logistic IRT Model

ERIC Educational Resources Information Center

Lamsal, Sunil

2015-01-01

Different estimation procedures have been developed for the unidimensional three-parameter item response theory (IRT) model. These techniques include the marginal maximum likelihood estimation, the fully Bayesian estimation using Markov chain Monte Carlo simulation techniques, and the Metropolis-Hastings Robbin-Monro estimation. With each…

A novel method for expediting the development of patient-reported outcome measures and an evaluation across several populations

PubMed Central

Garrard, Lili; Price, Larry R.; Bott, Marjorie J.; Gajewski, Byron J.

2016-01-01

Item response theory (IRT) models provide an appropriate alternative to the classical ordinal confirmatory factor analysis (CFA) during the development of patient-reported outcome measures (PROMs). Current literature has identified the assessment of IRT model fit as both challenging and underdeveloped (Sinharay & Johnson, 2003; Sinharay, Johnson, & Stern, 2006). This study evaluates the performance of Ordinal Bayesian Instrument Development (OBID), a Bayesian IRT model with a probit link function approach, through applications in two breast cancer-related instrument development studies. The primary focus is to investigate an appropriate method for comparing Bayesian IRT models in PROMs development. An exact Bayesian leave-one-out cross-validation (LOO-CV) approach (Vehtari & Lampinen, 2002) is implemented to assess prior selection for the item discrimination parameter in the IRT model and subject content experts’ bias (in a statistical sense and not to be confused with psychometric bias as in differential item functioning) toward the estimation of item-to-domain correlations. Results support the utilization of content subject experts’ information in establishing evidence for construct validity when sample size is small. However, the incorporation of subject experts’ content information in the OBID approach can be sensitive to the level of expertise of the recruited experts. More stringent efforts need to be invested in the appropriate selection of subject experts to efficiently use the OBID approach and reduce potential bias during PROMs development. PMID:27667878

A novel method for expediting the development of patient-reported outcome measures and an evaluation across several populations.

PubMed

Garrard, Lili; Price, Larry R; Bott, Marjorie J; Gajewski, Byron J

2016-10-01

Item response theory (IRT) models provide an appropriate alternative to the classical ordinal confirmatory factor analysis (CFA) during the development of patient-reported outcome measures (PROMs). Current literature has identified the assessment of IRT model fit as both challenging and underdeveloped (Sinharay & Johnson, 2003; Sinharay, Johnson, & Stern, 2006). This study evaluates the performance of Ordinal Bayesian Instrument Development (OBID), a Bayesian IRT model with a probit link function approach, through applications in two breast cancer-related instrument development studies. The primary focus is to investigate an appropriate method for comparing Bayesian IRT models in PROMs development. An exact Bayesian leave-one-out cross-validation (LOO-CV) approach (Vehtari & Lampinen, 2002) is implemented to assess prior selection for the item discrimination parameter in the IRT model and subject content experts' bias (in a statistical sense and not to be confused with psychometric bias as in differential item functioning) toward the estimation of item-to-domain correlations. Results support the utilization of content subject experts' information in establishing evidence for construct validity when sample size is small. However, the incorporation of subject experts' content information in the OBID approach can be sensitive to the level of expertise of the recruited experts. More stringent efforts need to be invested in the appropriate selection of subject experts to efficiently use the OBID approach and reduce potential bias during PROMs development.

Recent use of medical infrared thermography in skin neoplasms.

PubMed

Magalhaes, C; Vardasca, R; Mendes, J

2018-03-25

Infrared thermal imaging captures the infrared radiation emitted by the skin surface. The thermograms contain valuable information, since the temperature distribution can be used to characterize physiological anomalies. Thus, the use of infrared thermal imaging (IRT) has been studied as a possible medical tool to aid in the diagnosis of skin oncological lesions. The aim of this review is to assess the current state of the applications of IRT in skin neoplasm identification and characterization. A literature survey was conducted using the reference bibliographic databases: Scopus, PubMed and ISI Web of Science. Keywords (thermography, infrared imaging, thermal imaging and skin cancer) were combined and its presence was verified at the title and abstract of the article or as a main topic. Only articles published after 2013 were considered during this search. In total, 55 articles were encountered, resulting in 14 publications for revision after applying the exclusion criteria. It was denoted that IRT have been used to characterize and distinguish between malignant and benign neoplasms and different skin cancer types. IRT has also been successfully applied in the treatment evaluation of these types of lesions. Trends and future challenges have been established to improve the application of IRT in this field, disclosing that dynamic thermography is a promising tool for early identification of oncological skin conditions. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Large and Small Droplet Impingement Data on Airfoils and Two Simulated Ice Shapes

NASA Technical Reports Server (NTRS)

Papadakis, Michael; Wong, See-Cheuk; Rachman, Arief; Hung, Kuohsing E.; Vu, Giao T.; Bidwell, Colin S.

2007-01-01

Water droplet impingement data were obtained at the NASA Glenn Icing Research Tunnel (IRT) for four wings and one wing with two simulated ice shapes. The wings tested include three 36-in. chord wings (MS(1)-317, GLC-305, and a NACA 652-415) and a 57-in. chord Twin Otter horizontal tail section. The simulated ice shapes were 22.5- and 45-min glaze ice shapes for the Twin Otter horizontal tail section generated using the LEWICE 2.2 ice accretion program. The impingement experiments were performed with spray clouds having median volumetric diameters of 11, 21, 79, 137, and 168 mm. Comparisons to the experimental data were generated which showed good agreement for the clean wings and ice shapes at lower drop sizes. For larger drop sizes LEWICE 2.2 over predicted the collection efficiencies due to droplet splashing effects which were not modeled in the program. Also for the more complex glaze ice shapes interpolation errors resulted in the over prediction of collection efficiencies in cove and shadow regions of ice shapes.

Parent Ratings of ADHD Symptoms: Generalized Partial Credit Model Analysis of Differential Item Functioning across Gender

ERIC Educational Resources Information Center

Gomez, Rapson

2012-01-01

Objective: Generalized partial credit model, which is based on item response theory (IRT), was used to test differential item functioning (DIF) for the "Diagnostic and Statistical Manual of Mental Disorders" (4th ed.), inattention (IA), and hyperactivity/impulsivity (HI) symptoms across boys and girls. Method: To accomplish this, parents completed…

Item Analysis and Differential Item Functioning of a Brief Conduct Problem Screen

ERIC Educational Resources Information Center

Wu, Johnny; King, Kevin M.; Witkiewitz, Katie; Racz, Sarah Jensen; McMahon, Robert J.

2012-01-01

Research has shown that boys display higher levels of childhood conduct problems than girls, and Black children display higher levels than White children, but few studies have tested for scalar equivalence of conduct problems across gender and race. The authors conducted a 2-parameter item response theory (IRT) model to examine item…

Instructional Strategies for Vocabulary Development in the Context of a Prescriptive Model

DTIC Science & Technology

1978-12-01

sycophant, type: NOT A SYCOPHANT. A second-string football player apple-polishing the coaches in order to get a starting position on the team J V Figure...irt in *-* w Q. ft ES3 c" o .--^- . ^—• - -2. Tables 2 and 3 shew the mean performance on severai criterion tests of Mie instructiorial

Bayesian Analysis of Multidimensional Item Response Theory Models: A Discussion and Illustration of Three Response Style Models

ERIC Educational Resources Information Center

Leventhal, Brian C.; Stone, Clement A.

2018-01-01

Interest in Bayesian analysis of item response theory (IRT) models has grown tremendously due to the appeal of the paradigm among psychometricians, advantages of these methods when analyzing complex models, and availability of general-purpose software. Possible models include models which reflect multidimensionality due to designed test structure,…

A Mixture Rasch Model with a Covariate: A Simulation Study via Bayesian Markov Chain Monte Carlo Estimation

ERIC Educational Resources Information Center

Dai, Yunyun

2013-01-01

Mixtures of item response theory (IRT) models have been proposed as a technique to explore response patterns in test data related to cognitive strategies, instructional sensitivity, and differential item functioning (DIF). Estimation proves challenging due to difficulties in identification and questions of effect size needed to recover underlying…

Two Prophecy Formulas for Assessing the Reliability of Item Response Theory-Based Ability Estimates

ERIC Educational Resources Information Center

Raju, Nambury S.; Oshima, T.C.

2005-01-01

Two new prophecy formulas for estimating item response theory (IRT)-based reliability of a shortened or lengthened test are proposed. Some of the relationships between the two formulas, one of which is identical to the well-known Spearman-Brown prophecy formula, are examined and illustrated. The major assumptions underlying these formulas are…

The Impact of Item Position Change on Item Parameters and Common Equating Results under the 3PL Model

ERIC Educational Resources Information Center

Meyers, Jason L.; Murphy, Stephen; Goodman, Joshua; Turhan, Ahmet

2012-01-01

Operational testing programs employing item response theory (IRT) applications benefit from of the property of item parameter invariance whereby item parameter estimates obtained from one sample can be applied to other samples (when the underlying assumptions are satisfied). In theory, this feature allows for applications such as computer-adaptive…

An Evaluation of a New Method of IRT Scaling

ERIC Educational Resources Information Center

Ragland, Shelley

2010-01-01

In order to be able to fairly compare scores derived from different forms of the same test within the Item Response Theory framework, all individual item parameters must be on the same scale. A new approach, the RPA method, which is based on transformations of predicted score distributions was evaluated here and was shown to produce results…

IRT Models for Ability-Based Guessing

ERIC Educational Resources Information Center

Martin, Ernesto San; del Pino, Guido; De Boeck, Paul

2006-01-01

An ability-based guessing model is formulated and applied to several data sets regarding educational tests in language and in mathematics. The formulation of the model is such that the probability of a correct guess does not only depend on the item but also on the ability of the individual, weighted with a general discrimination parameter. By so…

Modeling Skipped and Not-Reached Items Using IRTrees

ERIC Educational Resources Information Center

Debeer, Dries; Janssen, Rianne; De Boeck, Paul

2017-01-01

When dealing with missing responses, two types of omissions can be discerned: items can be skipped or not reached by the test taker. When the occurrence of these omissions is related to the proficiency process the missingness is nonignorable. The purpose of this article is to present a tree-based IRT framework for modeling responses and omissions…

A Comparative Study of Test Data Dimensionality Assessment Procedures Under Nonparametric IRT Models

ERIC Educational Resources Information Center

van Abswoude, Alexandra A. H.; van der Ark, L. Andries; Sijtsma, Klaas

2004-01-01

In this article, an overview of nonparametric item response theory methods for determining the dimensionality of item response data is provided. Four methods were considered: MSP, DETECT, HCA/CCPROX, and DIMTEST. First, the methods were compared theoretically. Second, a simulation study was done to compare the effectiveness of MSP, DETECT, and…

Additional Study of Water Droplet Median Volume Diameter (MVD) Effects on Ice Shapes

NASA Technical Reports Server (NTRS)

Tsao, Jen-Ching; Anderson, David N.

2005-01-01

This paper reports the result of an experimental study in the NASA Glenn Icing Research Tunnel (IRT) to evaluate how well the MVD-independent effect identified previously might apply to SLD conditions in rime icing situations. Models were NACA 0012 wing sections with chords of 53.3 and 91.4 cm. Tests were conducted with a nominal airspeed of 77 m/s (150 kt) and a number of MVD's ranging from 15 to 100 m with LWC of 0.5 to 1 g/cu m. In the present study, ice shapes recorded from past studies and recent results at SLD and Appendix-C conditions are reviewed to show that droplet diameter is not important to rime ice shape for MVD of 30 microns or larger, but for less than 30 m drop sizes a rime ice shape transition from convex to wedge to spearhead type ice shape is observed.

Evaluating Equating Accuracy and Assumptions for Groups that Differ in Performance

ERIC Educational Resources Information Center

Powers, Sonya; Kolen, Michael J.

2014-01-01

Accurate equating results are essential when comparing examinee scores across exam forms. Previous research indicates that equating results may not be accurate when group differences are large. This study compared the equating results of frequency estimation, chained equipercentile, item response theory (IRT) true-score, and IRT observed-score…

Estimating a Noncompensatory IRT Model Using Metropolis within Gibbs Sampling

ERIC Educational Resources Information Center

Babcock, Ben

2011-01-01

Relatively little research has been conducted with the noncompensatory class of multidimensional item response theory (MIRT) models. A Monte Carlo simulation study was conducted exploring the estimation of a two-parameter noncompensatory item response theory (IRT) model. The estimation method used was a Metropolis-Hastings within Gibbs algorithm…

Practical Guide to Conducting an Item Response Theory Analysis

ERIC Educational Resources Information Center

Toland, Michael D.

2014-01-01

Item response theory (IRT) is a psychometric technique used in the development, evaluation, improvement, and scoring of multi-item scales. This pedagogical article provides the necessary information needed to understand how to conduct, interpret, and report results from two commonly used ordered polytomous IRT models (Samejima's graded…

IRT Item Parameter Recovery with Marginal Maximum Likelihood Estimation Using Loglinear Smoothing Models

ERIC Educational Resources Information Center

Casabianca, Jodi M.; Lewis, Charles

2015-01-01

Loglinear smoothing (LLS) estimates the latent trait distribution while making fewer assumptions about its form and maintaining parsimony, thus leading to more precise item response theory (IRT) item parameter estimates than standard marginal maximum likelihood (MML). This article provides the expectation-maximization algorithm for MML estimation…

Stochastic Ordering Using the Latent Trait and the Sum Score in Polytomous IRT Models.

ERIC Educational Resources Information Center

Hemker, Bas T.; Sijtsma, Klaas; Molenaar, Ivo W.; Junker, Brian W.

1997-01-01

Stochastic ordering properties are investigated for a broad class of item response theory (IRT) models for which the monotone likelihood ratio does not hold. A taxonomy is given for nonparametric and parametric models for polytomous models based on the hierarchical relationship between the models. (SLD)

Modelling Mathematics Problem Solving Item Responses Using a Multidimensional IRT Model

ERIC Educational Resources Information Center

Wu, Margaret; Adams, Raymond

2006-01-01

This research examined students' responses to mathematics problem-solving tasks and applied a general multidimensional IRT model at the response category level. In doing so, cognitive processes were identified and modelled through item response modelling to extract more information than would be provided using conventional practices in scoring…

Model Selection Indices for Polytomous Items

ERIC Educational Resources Information Center

Kang, Taehoon; Cohen, Allan S.; Sung, Hyun-Jung

2009-01-01

This study examines the utility of four indices for use in model selection with nested and nonnested polytomous item response theory (IRT) models: a cross-validation index and three information-based indices. Four commonly used polytomous IRT models are considered: the graded response model, the generalized partial credit model, the partial credit…

Assessing Equating Results on Different Equating Criteria

ERIC Educational Resources Information Center

Tong, Ye; Kolen, Michael

2005-01-01

The performance of three equating methods--the presmoothed equipercentile method, the item response theory (IRT) true score method, and the IRT observed score method--were examined based on three equating criteria: the same distributions property, the first-order equity property, and the second-order equity property. The magnitude of the…

On the Bayesian Nonparametric Generalization of IRT-Type Models

ERIC Educational Resources Information Center

San Martin, Ernesto; Jara, Alejandro; Rolin, Jean-Marie; Mouchart, Michel

2011-01-01

We study the identification and consistency of Bayesian semiparametric IRT-type models, where the uncertainty on the abilities' distribution is modeled using a prior distribution on the space of probability measures. We show that for the semiparametric Rasch Poisson counts model, simple restrictions ensure the identification of a general…

IRTs of the ABCs: Children's Letter Name Acquisition

ERIC Educational Resources Information Center

Phillips, Beth M.; Piasta, Shayne B.; Anthony, Jason L.; Lonigan, Christopher J.; Francis, David J.

2012-01-01

We examined the developmental sequence of letter name knowledge acquisition by children from 2 to five years of age. Data from 2 samples representing diverse regions, ethnicity, and socioeconomic backgrounds (ns=1074 and 500) were analyzed using item response theory (IRT) and differential item functioning techniques. Results from factor analyses…

Assessment of a Technique for Estimating Total Column Water Vapor Using Measurements of the Infrared Sky Temperature

NASA Technical Reports Server (NTRS)

Merceret, Francis J.; Huddleston, Lisa L.

2014-01-01

A method for estimating the integrated precipitable water (IPW) content of the atmosphere using measurements of indicated infrared zenith sky temperature was validated over east-central Florida. The method uses inexpensive, commercial off the shelf, hand-held infrared thermometers (IRT). Two such IRTs were obtained from a commercial vendor, calibrated against several laboratory reference sources at KSC, and used to make IR zenith sky temperature measurements in the vicinity of KSC and Cape Canaveral Air Force Station (CCAFS). The calibration and comparison data showed that these inexpensive IRTs provided reliable, stable IR temperature measurements that were well correlated with the NOAA IPW observations.

Goodness of Model-Data Fit and Invariant Measurement

ERIC Educational Resources Information Center

Engelhard, George, Jr.; Perkins, Aminah

2013-01-01

In this commentary, Englehard and Perkins remark that Maydeu-Olivares has presented a framework for evaluating the goodness of model-data fit for item response theory (IRT) models and correctly points out that overall goodness-of-fit evaluations of IRT models and data are not generally explored within most applications in educational and…

Optimal Item Selection with Credentialing Examinations.

ERIC Educational Resources Information Center

Hambleton, Ronald K.; And Others

The study compared two promising item response theory (IRT) item-selection methods, optimal and content-optimal, with two non-IRT item selection methods, random and classical, for use in fixed-length certification exams. The four methods were used to construct 20-item exams from a pool of approximately 250 items taken from a 1985 certification…

The Effect of Year-to-Year Rater Variation on IRT Linking

ERIC Educational Resources Information Center

Yen, Shu Jing; Ochieng, Charles; Michaels, Hillary; Friedman, Greg

2005-01-01

Year-to-year rater variation may result in constructed response (CR) parameter changes, making CR items inappropriate to use in anchor sets for linking or equating. This study demonstrates how rater severity affected the writing and reading scores. Rater adjustments were made to statewide results using an item response theory (IRT) methodology…

Obstacles to Developing Digital Literacy on the Internet in Middle School Science Instruction

ERIC Educational Resources Information Center

Colwell, Jamie; Hunt-Barron, Sarah; Reinking, David

2013-01-01

Obstacles, and instructional responses to them, that emerged in two middle school science classes during a formative experiment investigating Internet Reciprocal Teaching (IRT), an instructional intervention aimed at increasing digital literacy on the Internet, are reported in this manuscript. Analysis of qualitative data revealed that IRT enabled…

Preequating with Empirical Item Characteristic Curves: An Observed-Score Preequating Method

ERIC Educational Resources Information Center

Zu, Jiyun; Puhan, Gautam

2014-01-01

Preequating is in demand because it reduces score reporting time. In this article, we evaluated an observed-score preequating method: the empirical item characteristic curve (EICC) method, which makes preequating without item response theory (IRT) possible. EICC preequating results were compared with a criterion equating and with IRT true-score…

Extended Mixed-Efects Item Response Models with the MH-RM Algorithm

ERIC Educational Resources Information Center

Chalmers, R. Philip

2015-01-01

A mixed-effects item response theory (IRT) model is presented as a logical extension of the generalized linear mixed-effects modeling approach to formulating explanatory IRT models. Fixed and random coefficients in the extended model are estimated using a Metropolis-Hastings Robbins-Monro (MH-RM) stochastic imputation algorithm to accommodate for…

Distinguishing Continuous and Discrete Approaches to Multilevel Mixture IRT Models: A Model Comparison Perspective

ERIC Educational Resources Information Center

Zhu, Xiaoshu

2013-01-01

The current study introduced a general modeling framework, multilevel mixture IRT (MMIRT) which detects and describes characteristics of population heterogeneity, while accommodating the hierarchical data structure. In addition to introducing both continuous and discrete approaches to MMIRT, the main focus of the current study was to distinguish…

New Method of Calibrating IRT Models.

ERIC Educational Resources Information Center

Jiang, Hai; Tang, K. Linda

This discussion of new methods for calibrating item response theory (IRT) models looks into new optimization procedures, such as the Genetic Algorithm (GA) to improve on the use of the Newton-Raphson procedure. The advantages of using a global optimization procedure like GA is that this kind of procedure is not easily affected by local optima and…

Applying Kaplan-Meier to Item Response Data

ERIC Educational Resources Information Center

McNeish, Daniel

2018-01-01

Some IRT models can be equivalently modeled in alternative frameworks such as logistic regression. Logistic regression can also model time-to-event data, which concerns the probability of an event occurring over time. Using the relation between time-to-event models and logistic regression and the relation between logistic regression and IRT, this…

Five Methods for Estimating Angoff Cut Scores with IRT

ERIC Educational Resources Information Center

Wyse, Adam E.

2017-01-01

This article illustrates five different methods for estimating Angoff cut scores using item response theory (IRT) models. These include maximum likelihood (ML), expected a priori (EAP), modal a priori (MAP), and weighted maximum likelihood (WML) estimators, as well as the most commonly used approach based on translating ratings through the test…

Bayesian Estimation of the Logistic Positive Exponent IRT Model

ERIC Educational Resources Information Center

Bolfarine, Heleno; Bazan, Jorge Luis

2010-01-01

A Bayesian inference approach using Markov Chain Monte Carlo (MCMC) is developed for the logistic positive exponent (LPE) model proposed by Samejima and for a new skewed Logistic Item Response Theory (IRT) model, named Reflection LPE model. Both models lead to asymmetric item characteristic curves (ICC) and can be appropriate because a symmetric…

Unidimensional and Multidimensional Models for Item Response Theory.

ERIC Educational Resources Information Center

McDonald, Roderick P.

This paper provides an up-to-date review of the relationship between item response theory (IRT) and (nonlinear) common factor theory and draws out of this relationship some implications for current and future research in IRT. Nonlinear common factor analysis yields a natural embodiment of the weak principle of local independence in appropriate…

Random Item IRT Models

ERIC Educational Resources Information Center

De Boeck, Paul

2008-01-01

It is common practice in IRT to consider items as fixed and persons as random. Both, continuous and categorical person parameters are most often random variables, whereas for items only continuous parameters are used and they are commonly of the fixed type, although exceptions occur. It is shown in the present article that random item parameters…

Finite Mixture Multilevel Multidimensional Ordinal IRT Models for Large Scale Cross-Cultural Research

ERIC Educational Resources Information Center

de Jong, Martijn G.; Steenkamp, Jan-Benedict E. M.

2010-01-01

We present a class of finite mixture multilevel multidimensional ordinal IRT models for large scale cross-cultural research. Our model is proposed for confirmatory research settings. Our prior for item parameters is a mixture distribution to accommodate situations where different groups of countries have different measurement operations, while…

The Information Function for the One-Parameter Logistic Model: Is it Reliability?

ERIC Educational Resources Information Center

Doran, Harold C.

2005-01-01

The information function is an important statistic in item response theory (IRT) applications. Although the information function is often described as the IRT version of reliability, it differs from the classical notion of reliability from a critical perspective: replication. This article first explores the information function for the…

Risky Business: Understanding Student Intellectual Risk Taking in Management Education

ERIC Educational Resources Information Center

Dachner, Alison M.; Miguel, Rosanna F.; Patena, Rachel A.

2017-01-01

The demands of today's ever-changing work environment often require that employees engage in intellectual risk taking (IRT) by being resourceful, trying new things, and asking questions even at the risk of making a mistake or feeling inadequate. This research seeks to identify variables that increase student IRT. Controlling for individual…

Distance Education Infrastructure for Rural Areas Using Java as a Development Tool.

ERIC Educational Resources Information Center

Ndinga, S. S.; Clayton, P.

New information technology is rapidly becoming part of the localized education process, while offering the tools and the infrastructure for the establishment of a distance education process. At Rhodes University (South Africa), an Interactive Remote Tutorial System (IRTS) was built to support distance education. IRTS will be used as an…

IRT-ZIP Modeling for Multivariate Zero-Inflated Count Data

ERIC Educational Resources Information Center

Wang, Lijuan

2010-01-01

This study introduces an item response theory-zero-inflated Poisson (IRT-ZIP) model to investigate psychometric properties of multiple items and predict individuals' latent trait scores for multivariate zero-inflated count data. In the model, two link functions are used to capture two processes of the zero-inflated count data. Item parameters are…

The Infrared-Optical Telescope (IRT) of the Exist Observatory

NASA Technical Reports Server (NTRS)

Kutyrev, Alexander; Bloom, Joshua; Gehrels, Neil; Golisano, Craig; Gong, Quan; Grindlay, Jonathan; Moseley, Samuel; Woodgate, Bruce

2010-01-01

The IRT is a 1.1m visible and infrared passively cooled telescope, which can locate, identify and obtain spectra of GRB afterglows at redshifts up to z 20. It will also acquire optical-IR, imaging and spectroscopy of AGN and transients discovered by the EXIST (The Energetic X-ray Imaging Survey Telescope). The IRT imaging and spectroscopic capabilities cover a broad spectral range from 0.32.2m in four bands. The identical fields of view in the four instrument bands are each split in three subfields: imaging, objective prism slitless for the field and objective prism single object slit low resolution spectroscopy, and high resolution long slit on single object. This allows the instrument, to do simultaneous broadband photometry or spectroscopy of the same object over the full spectral range, thus greatly improving the efficiency of the observatory and its detection limits. A prompt follow up (within three minutes) of the transient discovered by the EXIST makes IRT a unique tool for detection and study of these events, which is particularly valuable at wavelengths unavailable to the ground based observatories.

Personality Polygenes, Positive Affect, and Life Satisfaction

PubMed Central

Weiss, Alexander; Baselmans, Bart M. L.; Hofer, Edith; Yang, Jingyun; Okbay, Aysu; Lind, Penelope A.; Miller, Mike B.; Nolte, Ilja M.; Zhao, Wei; Hagenaars, Saskia P.; Hottenga, Jouke-Jan; Matteson, Lindsay K.; Snieder, Harold; Faul, Jessica D.; Hartman, Catharina A.; Boyle, Patricia A.; Tiemeier, Henning; Mosing, Miriam A.; Pattie, Alison; Davies, Gail; Liewald, David C.; Schmidt, Reinhold; De Jager, Philip L.; Heath, Andrew C.; Jokela, Markus; Starr, John M.; Oldehinkel, Albertine J.; Johannesson, Magnus; Cesarini, David; Hofman, Albert; Harris, Sarah E.; Smith, Jennifer A.; Keltikangas-Järvinen, Liisa; Pulkki-Råback, Laura; Schmidt, Helena; Smith, Jacqui; Iacono, William G.; McGue, Matt; Bennett, David A.; Pedersen, Nancy L.; Magnusson, Patrik K. E.; Deary, Ian J.; Martin, Nicholas G.; Boomsma, Dorret I.; Bartels, Meike; Luciano, Michelle

2016-01-01

Approximately half of the variation in wellbeing measures overlaps with variation in personality traits. Studies of non-human primate pedigrees and human twins suggest that this is due to common genetic influences. We tested whether personality polygenic scores for the NEO Five-Factor Inventory (NEO-FFI) domains and for item response theory (IRT) derived extraversion and neuroticism scores predict variance in wellbeing measures. Polygenic scores were based on published genome-wide association (GWA) results in over 17,000 individuals for the NEO-FFI and in over 63,000 for the IRT extraversion and neuroticism traits. The NEO-FFI polygenic scores were used to predict life satisfaction in 7 cohorts, positive affect in 12 cohorts, and general wellbeing in 1 cohort (maximal N = 46,508). Meta-analysis of these results showed no significant association between NEO-FFI personality polygenic scores and the wellbeing measures. IRT extraversion and neuroticism polygenic scores were used to predict life satisfaction and positive affect in almost 37,000 individuals from UK Biobank. Significant positive associations (effect sizes <0.05%) were observed between the extraversion polygenic score and wellbeing measures, and a negative association was observed between the polygenic neuroticism score and life satisfaction. Furthermore, using GWA data, genetic correlations of −0.49 and −0.55 were estimated between neuroticism with life satisfaction and positive affect, respectively. The moderate genetic correlation between neuroticism and wellbeing is in line with twin research showing that genetic influences on wellbeing are also shared with other independent personality domains. PMID:27546527

Induction of Nickel Accumulation in Response to Zinc Deficiency in Arabidopsis thaliana

PubMed Central

Nishida, Sho; Kato, Aki; Tsuzuki, Chisato; Yoshida, Junko; Mizuno, Takafumi

2015-01-01

Excessive accumulation of nickel (Ni) can be toxic to plants. In Arabidopsis thaliana, the Fe2+ transporter, iron (Fe)-regulated transporter1 (IRT1), mediates Fe uptake and also implicates in Ni2+ uptake at roots; however, the underlying mechanism of Ni2+ uptake and accumulation remains unelucidated. In the present study, we found that zinc (Zn) deficient conditions resulted in increased accumulation of Ni in plants, particularly in roots, in A. thaliana. In order to elucidate the underlying mechanisms of Ni uptake correlating zinc condition, we traced 63Ni isotope in response to Zn and found that (i) Zn deficiency induces short-term Ni2+ absorption and (ii) Zn2+ inhibits Ni2+ uptake, suggesting competitive uptake between Ni and Zn. Furthermore, the Zrt/Irt-like protein 3 (ZIP3)-defective mutant with an elevated Zn-deficient response exhibited higher Ni accumulation than the wild type, further supporting that the response to Zn deficiency induces Ni accumulation. Previously, expression profile study demonstrated that IRT1 expression is not inducible by Zn deficiency. In the present study, we found increased Ni accumulation in IRT1-null mutant under Zn deficiency in agar culture. These suggest that Zn deficiency induces Ni accumulation in an IRT1-independen manner. The present study revealed that Ni accumulation is inducible in response to Zn deficiency, which may be attributable to a Zn uptake transporter induced by Zn deficiency. PMID:25923075

Effect of the stimulus frequency and pulse number of repetitive transcranial magnetic stimulation on the inter-reversal time of perceptual reversal on the right superior parietal lobule

NASA Astrophysics Data System (ADS)

Nojima, Kazuhisa; Ge, Sheng; Katayama, Yoshinori; Ueno, Shoogo; Iramina, Keiji

2010-05-01

The aim of this study is to investigate the effect of the stimulus frequency and pulses number of repetitive transcranial magnetic stimulation (rTMS) on the inter-reversal time (IRT) of perceptual reversal on the right superior parietal lobule (SPL). The spinning wheel illusion was used as the ambiguous figures stimulation in this study. To investigate the rTMS effect over the right SPL during perceptual reversal, 0.25 Hz 60 pulse, 1 Hz 60 pulse, 0.5 Hz 120 pulse, 1 Hz 120 pulse, and 1 Hz 240 pulse biphasic rTMS at 90% of resting motor threshold was applied over the right SPL and the right posterior temporal lobe (PTL), respectively. As a control, a no TMS was also conducted. It was found that rTMS on 0.25 Hz 60 pulse and 1 Hz 60 pulse applied over the right SPL caused shorter IRT. In contrast, it was found that rTMS on 1 Hz 240-pulse applied over the right SPL caused longer IRT. On the other hand, there is no significant difference between IRTs when the rTMS on 0.5 Hz 120 pulse and 1 Hz 120 pulse were applied over the right SPL. Therefore, the applying of rTMS over the right SPL suggests that the IRT of perceptual reversal is effected by the rTMS conditions such as the stimulus frequency and the number of pulses.

Partially Observed Mixtures of IRT Models: An Extension of the Generalized Partial-Credit Model

ERIC Educational Resources Information Center

Von Davier, Matthias; Yamamoto, Kentaro

2004-01-01

The generalized partial-credit model (GPCM) is used frequently in educational testing and in large-scale assessments for analyzing polytomous data. Special cases of the generalized partial-credit model are the partial-credit model--or Rasch model for ordinal data--and the two parameter logistic (2PL) model. This article extends the GPCM to the…

The Impact of Multidirectional Item Parameter Drift on IRT Scaling Coefficients and Proficiency Estimates

ERIC Educational Resources Information Center

Han, Kyung T.; Wells, Craig S.; Sireci, Stephen G.

2012-01-01

Item parameter drift (IPD) occurs when item parameter values change from their original value over time. IPD may pose a serious threat to the fairness and validity of test score interpretations, especially when the goal of the assessment is to measure growth or improvement. In this study, we examined the effect of multidirectional IPD (i.e., some…

A New Statistic for Evaluating Item Response Theory Models for Ordinal Data. CRESST Report 839

ERIC Educational Resources Information Center

Cai, Li; Monroe, Scott

2014-01-01

We propose a new limited-information goodness of fit test statistic C[subscript 2] for ordinal IRT models. The construction of the new statistic lies formally between the M[subscript 2] statistic of Maydeu-Olivares and Joe (2006), which utilizes first and second order marginal probabilities, and the M*[subscript 2] statistic of Cai and Hansen…

Computer-adaptive test to measure community reintegration of Veterans.

PubMed

Resnik, Linda; Tian, Feng; Ni, Pengsheng; Jette, Alan

2012-01-01

The Community Reintegration of Injured Service Members (CRIS) measure consists of three scales measuring extent of, perceived limitations in, and satisfaction with community reintegration. Length of the CRIS may be a barrier to its widespread use. Using item response theory (IRT) and computer-adaptive test (CAT) methodologies, this study developed and evaluated a briefer community reintegration measure called the CRIS-CAT. Large item banks for each CRIS scale were constructed. A convenience sample of 517 Veterans responded to all items. Exploratory and confirmatory factor analyses (CFAs) were used to identify the dimensionality within each domain, and IRT methods were used to calibrate items. Accuracy and precision of CATs of different lengths were compared with the full-item bank, and data were examined for differential item functioning (DIF). CFAs supported unidimensionality of scales. Acceptable item fit statistics were found for final models. Accuracy of 10-, 15-, 20-, and variable-item CATs for all three scales was 0.88 or above. CAT precision increased with number of items administered and decreased at the upper ranges of each scale. Three items exhibited moderate DIF by sex. The CRIS-CAT demonstrated promising measurement properties and is recommended for use in community reintegration assessment.

Testing measurement invariance of the patient-reported outcomes measurement information system pain behaviors score between the US general population sample and a sample of individuals with chronic pain.

PubMed

Chung, Hyewon; Kim, Jiseon; Cook, Karon F; Askew, Robert L; Revicki, Dennis A; Amtmann, Dagmar

2014-02-01

In order to test the difference between group means, the construct measured must have the same meaning for all groups under investigation. This study examined the measurement invariance of responses to the patient-reported outcomes measurement information system (PROMIS) pain behavior (PB) item bank in two samples: the PROMIS calibration sample (Wave 1, N = 426) and a sample recruited from the American Chronic Pain Association (ACPA, N = 750). The ACPA data were collected to increase the number of participants with higher levels of pain. Multi-group confirmatory factor analysis (MG-CFA) and two item response theory (IRT)-based differential item functioning (DIF) approaches were employed to evaluate the existence of measurement invariance. MG-CFA results supported metric invariance of the PROMIS-PB, indicating unstandardized factor loadings with equal across samples. DIF analyses revealed that impact of 6 DIF items was negligible. Based on the results of both MG-CFA and IRT-based DIF approaches, we recommend retaining the original parameter estimates obtained from the combined samples based on the results of MG-CFA.

40,000 memories in young teenagers: Psychometric properties of the Autobiographical Memory Test in a UK cohort study

PubMed Central

Heron, Jon; Crane, Catherine; Gunnell, David; Lewis, Glyn; Evans, Jonathan; Williams, J. Mark G.

2012-01-01

Although the Autobiographical Memory Test (AMT) is widely used its psychometric properties have rarely been investigated. This paper utilises data gathered from a 10-item written version of the AMT, completed by 5792 adolescents participating in the Avon Longitudinal Study of Parents and Children, to examine the psychometric properties of the measure. The results show that the scale derived from responses to the AMT operates well over a wide range of scores, consistent with the aim of deriving a continuous measure of over-general memory. There was strong evidence of group differences in terms of gender, low negative mood, and IQ, and these were in agreement when comparing an item response theory (IRT) approach with that based on a sum score. One advantage of the IRT model is the ability to assess and consequently allow for differential item functioning. This additional analysis showed evidence of response bias for both gender and mood, resulting in attenuation in the mean differences in AMT across these groups. Implications of the findings for the use of the AMT measure in different samples are discussed. PMID:22348421

An Assessment of the SEA Multi-Element Sensor for Liquid Water Content Calibration of the NASA GRC Icing Research Tunnel

NASA Technical Reports Server (NTRS)

Steen, Laura E.; Ide, Robert F.; Van Zante, Judith F.

2015-01-01

The NASA Glenn Icing Research tunnel has been using an Icing Blade technique to measure cloud liquid water content (LWC) since 1980. The IRT conducted tests with SEA Multi-Element sensors from 2009 to 2011 to assess their performance in measuring LWC. These tests revealed that the Multi-Element sensors showed some significant advantages over the Icing Blade, particularly at higher water contents, higher impingement rates, and large drop sizes. Results of these and other tests are presented here.

Experimental Investigation of Ice Accretion Effects on a Swept Wing

NASA Technical Reports Server (NTRS)

Wong, S. C.; Vargas, M.; Papadakis, M.; Yeong, H. W.; Potapczuk, M.

2005-01-01

An experimental investigation was conducted to study the effects of 2-, 5-, 10-, and 22.5-min ice accretions on the aerodynamic performance of a swept finite wing. The ice shapes tested included castings of ice accretions obtained from icing tests at the NASA Glenn Icing Research Tunnel (IRT) and simulated ice shapes obtained with the LEWICE 2.0 ice accretion code. The conditions used for the icing tests were selected to provide five glaze ice shapes with complete and incomplete scallop features and a small rime ice shape. The LEWICE ice shapes were defined for the same conditions as those used in the icing tests. All aerodynamic performance tests were conducted in the 7- x 10-ft Low-Speed Wind Tunnel Facility at Wichita State University. Six component force and moment measurements, aileron hinge moments, and surface pressures were obtained for a Reynolds number of 1.8 million based on mean aerodynamic chord and aileron deflections in the range of -15o to 20o. Tests were performed with the clean wing, six IRT ice shape castings, seven smooth LEWICE ice shapes, and seven rough LEWICE ice shapes. Roughness for the LEWICE ice shapes was simulated with 36-size grit. The experiments conducted showed that the glaze ice castings reduced the maximum lift coefficient of the clean wing by 11.5% to 93.6%, while the 5-min rime ice casting increased maximum lift by 3.4%. Minimum iced wing drag was 133% to 3533% greater with respect to the clean case. The drag of the iced wing near the clean wing stall angle of attack was 17% to 104% higher than that of the clean case. In general, the aileron remained effective in changing the lift of the clean and iced wings for all angles of attack and aileron deflections tested. Aileron hinge moments for the iced wing cases remained within the maximum and minimum limits defined by the clean wing hinge moments. Tests conducted with the LEWICE ice shapes showed that in general the trends in aerodynamic performance degradation of the wing with the simulated ice shapes were similar to those obtained with the IRT ice shape castings. However, in most cases, the ice castings resulted in greater aerodynamic performance losses than those obtained with the LEWICE ice shapes. For the majority of the LEWICE ice shapes, the addition of 36-size grit roughness to the smooth ice shapes increased aerodynamic performance losses.

Item Response Theory Analyses of the Cambridge Face Memory Test (CFMT)

PubMed Central

Cho, Sun-Joo; Wilmer, Jeremy; Herzmann, Grit; McGugin, Rankin; Fiset, Daniel; Van Gulick, Ana E.; Ryan, Katie; Gauthier, Isabel

2014-01-01

We evaluated the psychometric properties of the Cambridge face memory test (CFMT; Duchaine & Nakayama, 2006). First, we assessed the dimensionality of the test with a bi-factor exploratory factor analysis (EFA). This EFA analysis revealed a general factor and three specific factors clustered by targets of CFMT. However, the three specific factors appeared to be minor factors that can be ignored. Second, we fit a unidimensional item response model. This item response model showed that the CFMT items could discriminate individuals at different ability levels and covered a wide range of the ability continuum. We found the CFMT to be particularly precise for a wide range of ability levels. Third, we implemented item response theory (IRT) differential item functioning (DIF) analyses for each gender group and two age groups (Age ≤ 20 versus Age > 21). This DIF analysis suggested little evidence of consequential differential functioning on the CFMT for these groups, supporting the use of the test to compare older to younger, or male to female, individuals. Fourth, we tested for a gender difference on the latent facial recognition ability with an explanatory item response model. We found a significant but small gender difference on the latent ability for face recognition, which was higher for women than men by 0.184, at age mean 23.2, controlling for linear and quadratic age effects. Finally, we discuss the practical considerations of the use of total scores versus IRT scale scores in applications of the CFMT. PMID:25642930

Proceedings of the Special Meeting on the Physics of Detectors Held at U.S. Naval Training Device Center, Orlando, Florida, on 15 March 1972

DTIC Science & Technology

1972-08-01

manufacture. The bias is well within the power rating of the device. -le havo also seer. similar noise in lead- sulphide detectors. The noiie shown xeseibles...University Syracuse, New York ABSTRACT (Unclassified) The recombination cross section for mercury -doped germanium has been measured between 4-40 K, irt...in the mercury -doped samples was accounted for by quantitatively determining the density of these centers from carrier concentration and mobility

Reaction Rate Data. Number 63. Resume of FY 78 DNA-Sponsored Chemistry/Physics Reaction Rate Research Programs.

DTIC Science & Technology

1977-12-01

related progress p reports concerning the DNA-sponsored effo rt s described herein. - ~~~ Submission of other pertinent informat ion of a related nature...Work Unit 06). 5 5. Atmospheric Chemical Sensitivity and Modeling Invesriga nons—M. Scheibe, MRC (Work Unit 09). 5 6. Low Energy Cross Sections for...Debris Metal Ions—R. Neynaber, D. Vroom . and l.A. Rutherford, IRT, Inc. (Work Unit 12). 5 7. E and F Region Rate Coefficients for Excited Positive

The nutrition for sport knowledge questionnaire (NSKQ): development and validation using classical test theory and Rasch analysis.

PubMed

Trakman, Gina Louise; Forsyth, Adrienne; Hoye, Russell; Belski, Regina

2017-01-01

Appropriate dietary intake can have a significant influence on athletic performance. There is a growing consensus on sports nutrition and professionals working with athletes often provide dietary education. However, due to the limitations of existing sports nutrition knowledge questionnaires, previous reports of athletes' nutrition knowledge may be inaccurate. An updated questionnaire has been developed based on a recent review of sports nutrition guidelines. The tool has been validated using a robust methodology that incorporates relevant techniques from classical test theory (CTT) and Item response theory (IRT), namely, Rasch analysis. The final questionnaire has 89 questions and six sub-sections (weight management, macronutrients, micronutrients, sports nutrition, supplements, and alcohol). The content and face validity of the tool have been confirmed based on feedback from expert sports dietitians and university sports students, respectively. The internal reliability of the questionnaire as a whole is high (KR = 0.88), and most sub-sections achieved an acceptable internal reliability. Construct validity has been confirmed, with an independent T-test revealing a significant ( p  < 0.001) difference in knowledge scores of nutrition (64 ± 16%) and non-nutrition students (51 ± 19%). Test-retest reliability has been assured, with a strong correlation ( r  = 0.92, p  < 0.001) between individuals' scores on two attempts of the test, 10 days to 2 weeks apart. Three of the sub-sections fit the Rasch Unidimensional Model. The final version of the questionnaire represents a significant improvement over previous tools. Each nutrition sub-section is unidimensional, and therefore researchers and practitioners can use these individually, as required. Use of the questionnaire will allow researchers to draw conclusions about the effectiveness of nutrition education programs, and differences in knowledge across athletes of varying ages, genders, and athletic calibres.

Analysis and Prediction of Ice Shedding for a Full-Scale Heated Tail Rotor

NASA Technical Reports Server (NTRS)

Kreeger, Richard E.; Work, Andrew; Douglass, Rebekah; Gazella, Matthew; Koster, Zakery; Turk, Jodi

2016-01-01

When helicopters are to fly in icing conditions, it is necessary to consider the possibility of ice shed from the rotor blades. In 2013, a series of tests were conducted on a heated tail rotor at NASA Glenn's Icing Research Tunnel (IRT). The tests produced several shed events that were captured on camera. Three of these shed events were captured at a sufficiently high frame rate to obtain multiple images of the shed ice in flight that had a sufficiently long section of shed ice for analysis. Analysis of these shed events is presented and compared to an analytical Shedding Trajectory Model (STM). The STM is developed and assumes that the ice breaks off instantly as it reaches the end of the blade, while frictional and viscous forces are used as parameters to fit the STM. The trajectory of each shed is compared to that predicted by the STM, where the STM provides information of the shed group of ice as a whole. The limitations of the model's underlying assumptions are discussed in comparison to experimental shed events.

Application of golay complementary coded excitation schemes for non-destructive testing of sandwich structures

NASA Astrophysics Data System (ADS)

Arora, Vanita; Mulaveesala, Ravibabu

2017-06-01

In recent years, InfraRed Thermography (IRT) has become a widely accepted non-destructive testing technique to evaluate the structural integrity of composite sandwich structures due to its full-field, remote, fast and in-service inspection capabilities. This paper presents a novel infrared thermographic approach named as Golay complementary coded thermal wave imaging is presented to detect disbonds in a sandwich structure having face sheets from Glass/Carbon Fibre Reinforced (GFR/CFR) laminates and core of the wooden block.

Item Response Data Analysis Using Stata Item Response Theory Package

ERIC Educational Resources Information Center

Yang, Ji Seung; Zheng, Xiaying

2018-01-01

The purpose of this article is to introduce and review the capability and performance of the Stata item response theory (IRT) package that is available from Stata v.14, 2015. Using a simulated data set and a publicly available item response data set extracted from Programme of International Student Assessment, we review the IRT package from…

A Note on the Equivalence between Observed and Expected Information Functions with Polytomous IRT Models

ERIC Educational Resources Information Center

Magis, David

2015-01-01

The purpose of this note is to study the equivalence of observed and expected (Fisher) information functions with polytomous item response theory (IRT) models. It is established that observed and expected information functions are equivalent for the class of divide-by-total models (including partial credit, generalized partial credit, rating…

Pretest-Posttest-Posttest Multilevel IRT Modeling of Competence Growth of Students in Higher Education in Germany

ERIC Educational Resources Information Center

Schmidt, Susanne; Zlatkin-Troitschanskaia, Olga; Fox, Jean-Paul

2016-01-01

Longitudinal research in higher education faces several challenges. Appropriate methods of analyzing competence growth of students are needed to deal with those challenges and thereby obtain valid results. In this article, a pretest-posttest-posttest multivariate multilevel IRT model for repeated measures is introduced which is designed to address…

Detecting DIF in Polytomous Items Using MACS, IRT and Ordinal Logistic Regression

ERIC Educational Resources Information Center

Elosua, Paula; Wells, Craig

2013-01-01

The purpose of the present study was to compare the Type I error rate and power of two model-based procedures, the mean and covariance structure model (MACS) and the item response theory (IRT), and an observed-score based procedure, ordinal logistic regression, for detecting differential item functioning (DIF) in polytomous items. A simulation…

Ramsay-Curve Item Response Theory for the Three-Parameter Logistic Item Response Model

ERIC Educational Resources Information Center

Woods, Carol M.

2008-01-01

In Ramsay-curve item response theory (RC-IRT), the latent variable distribution is estimated simultaneously with the item parameters of a unidimensional item response model using marginal maximum likelihood estimation. This study evaluates RC-IRT for the three-parameter logistic (3PL) model with comparisons to the normal model and to the empirical…

Case Study – Idling Reduction Technologies for Emergency Service Vehicles

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

Laughlin, Michael; Owens, Russell J.

2016-01-01

This case study explores the use of idle reduction technologies (IRTs) on emergency service vehicles in police, fire, and ambulance applications. Various commercially available IRT systems and approaches can decrease, or ultimately eliminate, engine idling. Fleets will thus save money on fuel, and will also decrease their criteria pollutant emissions, greenhouse gas emissions, and noise.

Measuring Constructs in Family Science: How Can Item Response Theory Improve Precision and Validity?

ERIC Educational Resources Information Center

Gordon, Rachel A.

2015-01-01

This article provides family scientists with an understanding of contemporary measurement perspectives and the ways in which item response theory (IRT) can be used to develop measures with desired evidence of precision and validity for research uses. The article offers a nontechnical introduction to some key features of IRT, including its…

Hybrid Model of IRT and Latent Class Models.

ERIC Educational Resources Information Center

Yamamoto, Kentaro

This study developed a hybrid of item response theory (IRT) models and latent class models, which combined the strengths of each type of model. The primary motivation for developing the new model is to describe characteristics of examinees' knowledge at the time of the examination. Hence, the application of the model lies mainly in so-called…

Translation Fidelity of Psychological Scales: An Item Response Theory Analysis of an Individualism-Collectivism Scale.

ERIC Educational Resources Information Center

Bontempo, Robert

1993-01-01

Describes a method for assessing the quality of translations based on item response theory (IRT). Results from the IRT technique with French and Chinese versions of a scale measuring individualism-collectivism for samples of 250 U.S., 357 French, and 290 Chinese undergraduates show how several biased items are detected. (SLD)

A Systematic Comparison between Classical Optimal Scaling and the Two-Parameter IRT Model

ERIC Educational Resources Information Center

Warrens, Matthijs J.; de Gruijter, Dato N. M.; Heiser, Willem J.

2007-01-01

In this article, the relationship between two alternative methods for the analysis of multivariate categorical data is systematically explored. It is shown that the person score of the first dimension of classical optimal scaling correlates strongly with the latent variable for the two-parameter item response theory (IRT) model. Next, under the…

ResidPlots-2: Computer Software for IRT Graphical Residual Analyses

ERIC Educational Resources Information Center

Liang, Tie; Han, Kyung T.; Hambleton, Ronald K.

2009-01-01

This article discusses the ResidPlots-2, a computer software that provides a powerful tool for IRT graphical residual analyses. ResidPlots-2 consists of two components: a component for computing residual statistics and another component for communicating with users and for plotting the residual graphs. The features of the ResidPlots-2 software are…

An Extension of Least Squares Estimation of IRT Linking Coefficients for the Graded Response Model

ERIC Educational Resources Information Center

Kim, Seonghoon

2010-01-01

The three types (generalized, unweighted, and weighted) of least squares methods, proposed by Ogasawara, for estimating item response theory (IRT) linking coefficients under dichotomous models are extended to the graded response model. A simulation study was conducted to confirm the accuracy of the extended formulas, and a real data study was…

Using SAS PROC MCMC for Item Response Theory Models

PubMed Central

Samonte, Kelli

2014-01-01

Interest in using Bayesian methods for estimating item response theory models has grown at a remarkable rate in recent years. This attentiveness to Bayesian estimation has also inspired a growth in available software such as WinBUGS, R packages, BMIRT, MPLUS, and SAS PROC MCMC. This article intends to provide an accessible overview of Bayesian methods in the context of item response theory to serve as a useful guide for practitioners in estimating and interpreting item response theory (IRT) models. Included is a description of the estimation procedure used by SAS PROC MCMC. Syntax is provided for estimation of both dichotomous and polytomous IRT models, as well as a discussion on how to extend the syntax to accommodate more complex IRT models. PMID:29795834

Structure and Measurement of Depression in Youth: Applying Item Response Theory to Clinical Data

PubMed Central

Cole, David A.; Cai, Li; Martin, Nina C.; Findling, Robert L; Youngstrom, Eric A.; Garber, Judy; Curry, John F.; Hyde, Janet S.; Essex, Marilyn J.; Compas, Bruce E.; Goodyer, Ian M.; Rohde, Paul; Stark, Kevin D.; Slattery, Marcia J.; Forehand, Rex

2013-01-01

Goals of the paper were to use item response theory (IRT) to assess the relation of depressive symptoms to the underlying dimension of depression and to demonstrate how IRT-based measurement strategies can yield more reliable data about depression severity than conventional symptom counts. Participants were 3403 clinic and nonclinic children and adolescents from 12 contributing samples, all of whom received the Kiddie Schedule of Affective Disorders and Schizophrenia for school-aged children. Results revealed that some symptoms reflected higher levels of depression and were more discriminating than others. Results further demonstrated that utilization of IRT-based information about symptom severity and discriminability in the measurement of depression severity can reduce measurement error and increase measurement fidelity. PMID:21534696

IRTs of the ABCs: Children's Letter Name Acquisition

PubMed Central

Piasta, Shayne B.; Anthony, Jason L.; Lonigan, Christopher J.; Francis, David J.

2015-01-01

We examined the developmental sequence of letter name knowledge acquisition by children from 2 to five years of age. Data from 2 samples representing diverse regions, ethnicity, and socioeconomic backgrounds (ns = 1074 & 500) were analyzed using item response theory (IRT) and differential item functioning techniques. Results from factor analyses indicated that letter name knowledge represented a unidimensional skill; IRT results yielded significant differences between letters in both difficulty and discrimination. Results also indicated an approximate developmental sequence in letter name learning for the simplest and most challenging to learn letters -- but with no clear sequence between these extremes. Findings also suggested that children were most likely to first learn their first initial. We discuss implications for assessment and instruction. PMID:22710016