This article illustrates the use of an explanatory item response modeling (EIRM) approach in the context of measuring group differences in science achievement. The distinction between item response models and EIRMs, recently elaborated by De Boeck and Wilson (2004), is presented within the statistical framework of generalized linear mixed models.…

For over 50 years, the overwhelming weight of evidence has been that subjects are able to make use of partial information when responding to multiple-choice items. The subject chooses the alternative which has given rise to the lowest mismatch, except that if this minimum mismatch is larger than some threshold, the question is left unanswered.…

The purpose of this study was to compare empirical and subjective procedures for identifying science test items which discriminate against males or females in a fifth grade population (n=926). Techniques such as the Mantel-Haenszel procedure enable test developers to use both a priori and ex post facto procedures to identify specific items that…