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…

An English placement test (PT) is an essential component of any foundation program. It helps place students into their suitable language proficiency level so that they do not spend time learning materials below or above their levels. It also helps teachers to prepare teaching materials to students of similar levels (Brown, 2004; Illinois, 2012).…