Identifying items with differential item functioning (DIF) in an assessment is a crucial step for achieving equitable measurement. One critical issue that has not been fully addressed with existing studies is how DIF items can be detected when data are multilevel. In the present study, we introduced a Lord's Wald X[superscript 2] test-based…

We conducted an extensive Monte Carlo study of factor-rotation local solutions (LS) in multidimensional, two-parameter logistic (M2PL) item response models. In this study, we simulated more than 19,200 data sets that were drawn from 96 model conditions and performed more than 7.6 million rotations to examine the influence of (a) slope parameter…

A procedure for item analysis using distance clustering is described. Items are grouped according to the predominant factors measured, regardless of what they are. The procedure provides an efficient method of treating unanswered items. (Author/RC)

An algorithm for item analysis in which item discrimination indices have been defined for the distractors as well as the correct answer is presented. Also, the concept of convergent and discriminant validity is applied to items instead of tests, and is discussed as an aid to item analysis. (Author/JKS)