Performance of the logistic regression (LR) procedure was compared to that of the Mantel Haenszel (MH) procedure in the detection of uniform and nonuniform differential item functioning on a simulation examining distributional properties of the LR and MH test statistics and the relative power of the two procedures. (SLD)

Equal percentile (EP) and partial credit (PC) equatings for raw scores from performance-based assessments with free-response items are compared through the use of data from the Maryland School Performance Assessment Program. Results suggest that EP and PC methods do not give equivalent results when distributions are markedly skewed. (SLD)

A mathematical model is proposed to describe how group differences in distributions of abilities, which are distinct from the target ability, influence the probability of a correct item response. In the multidimensional approach, differential item functioning is considered a function of the educational histories of the examinees. (SLD)