Differential item functioning (DIF) indicates the violation of the invariance assumption for instance in models based on item response theory (IRT). For item-wise DIF analysis using IRT, a common metric for the item parameters of the groups that are to be compared (e.g. for the reference and the focal group) is necessary. In the Rasch model, therefore, the same linear restriction is imposed in ...

BACKGROUND The Family Satisfaction with End-of-Life Care is an internationally used measure of satisfaction with cancer care. However, the Family Satisfaction with End-of-Life Care has not been studied for equivalence of item endorsement across different socio-demographic groups using differential item functioning. AIMS The aims of this secondary data analysis were (1) to examine potential di...

In this study, whether item position effects lead to DIF in the condition where different test booklets are used was investigated. To do methods of Lord’s chi-square and Raju’s unsigned area with 3PL model under without purification were used. When performance compared, it revealed that generally, method identified more items than did area. The differentiation respect resulted a higher number d...

This paper provides an introduction to two commonly used item response theory (IRT) models (the two-parameter logistic model and the graded response model). Throughout the paper, the Need for Cognition Scale (NCS) is used to help illustrate different features of the IRT model. After introducing the IRT models, I explore the assumptions these models make as well as ways to assess the extent to w...

The Wisconsin Schizotypy Scales are widely used for assessing schizotypy in nonclinical and clinical samples. However, they were developed using classical test theory (CTT) and have not had their psychometric properties examined with more sophisticated measurement models. The present study employed item response theory (IRT) as well as traditional CTT to examine psychometric properties of four ...

The authors present a didactic illustration of how item response theory (IRT) can be used to separate measurement bias from true group differences on homogeneous and heterogeneous scales. Several bias detection methods are illustrated with 12 unidimensional Minnesota Multiphasic Personality Inventory (MMPI) factor scales (Waller, 1999) and the 13 multidimensional MMPI validity and clinical scal...

BACKGROUND Modern psychometric methods based on item response theory (IRT) can be used to develop adaptive measures of health-related quality of life (HRQL). Adaptive assessment requires an item bank for each domain of HRQL. The purpose of this study was to develop item banks for five domains of HRQL relevant to arthritis. METHODS About 1,400 items were drawn from published questionnaires or ...

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 indicated that letter name knowledge represente...

There are two currently popular statistical frameworks for addressing measurement problems namely Classical Test Theory (CTT) and Item Response Theory (IRT). This study is aimed empirically to examine the similarities and differences in the parameters estimated using these two frameworks. For this purpose, firstly the model assumptions and the goodness of fit analyses were checked for IRT. The ...

The Psychopathy Checklist--Revised (PCL-R) is an important measure in both applied and research settings. Evidence for its validity is mostly derived from male Caucasian participants. PCL-R ratings of 359 Caucasian and 356 African American participants were compared using confirmatory factor analysis (CFA) and item response theory (IRT) analyses. Previous research has indicated that 13 items of...