The purpose of this ITEMS module is to provide an introduction to differential item functioning (DIF) analysis using mixture item response models. The mixture item response models for DIF analysis involve comparing item profiles across latent groups, instead of manifest groups. First, an overview of DIF analysis based on latent groups, called…

Discusses extending research into differential item functioning (DIF) to performance assessment and considers some of the best options available at this time. The most effective strategy for assessing DIF is to use a combination of several methods, preferably one from each of the observed score nonparametric, latent score nonparametric, and…

This article examines how psychometric models based on certain assumptions have come to be used counterproductively by many practitioners in ways that limit the kinds of conclusions that can be made. The general problem of the context's influence on performance is discussed, and some implications are drawn. (SLD)