The two studies reported on in this paper examine the features of words that distinguish students' performances on vocabulary assessments as a means of understanding what contributes to the ease or difficulty of vocabulary knowledge. The two studies differ in the type of assessment, the types of words that were studied, and the grade levels and…

In this article, preProgress in Reading Literacy Study (prePIRLS) 2011 data is used to compare the performance of different language of instruction groupings (English, Afrikaans and African languages) in primary schools on the more complex, higher-order reading comprehension items tested in a large-scale international test. PrePIRLS 2011…

Differential item functioning (DIF) assessment is key in score validation. When DIF is present scores may not accurately reflect the construct of interest for some groups of examinees, leading to incorrect conclusions from the scores. Given rising immigration, and the increased reliance of educational policymakers on cross-national assessments…