DETECTION OF DIFFERENTIAL ITEM FUNCTIONING IN MULTIPLE GROUPS

Detection of differential item functioning (DIF) is most often done be tween two groups of examinees under item response theory. It is someti mes important, however, to determine whether DIF is present in more th an two groups. In this article we present a method for detection of DI F in multiple groups. The method is closely related to Lord's chi-squa re for comparing vectors of item parameters estimated in two groups. A n example using real data is provided.