This study investigated the effects of linking potentially multidimensional test forms using the fixed item parameter calibration. Forms had equal or unequal total test difficulty with and without confounding difficulty. The mean square errors and bias of estimated item and ability parameters were compared across the various confounding tests. The…

Research shows that test method can exert a significant impact on test takers' performance and thereby contaminate test scores. We argue that common test method can exert the same effect as common stimuli and violate the conditional independence assumption of item response theory models because, in general, subsets of items which have a shared…

When a test is adapted from a source language (SL) into a target language (TL), the two forms are usually not psychometrically equivalent. If linking between test forms is necessary, those items that have had their psychometric characteristics altered by the translation (differential item functioning [DIF] items) should be eliminated from the…