Comparing language tests and test preparation materials holds important implications for the latter's validity and reliability. However, not enough studies compare such materials across a wide range of indices. Therefore, this study investigated the text complexity of IELTS academic reading tests (IRT) and IELTS reading practice tests (IRPrT).…

This study explores the extent to which topic and background knowledge of topic affect spoken performance in a high-stakes speaking test. It is argued that evidence of a substantial influence may introduce construct-irrelevant variance and undermine test fairness. Data were collected from 81 non-native speakers of English who performed on 10…

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…