Identifying the causes of DIF in translated verbal items

Translated tests are being used increasingly for assessing the knowledge and skills of individuals who speak different languages. There is little research exploring why translated items sometimes function differently across languages. If the sources of differential item functioning (DIF) across languages could be predicted, it could have important implications on test development, scoring and equating. This study focuses on two questions: "Is DIF related to item type?", "What are the causes of DIF?" The data were taken from the Israeli Psychometric Entrance Test in Hebrew (source) and Russian (translated). The results indicated that 34% of the items functioned differentially across languages. The analogy items were the most problematic with 65% showing DIF: mostly in favor of the Russian-speaking examinees. The sentence completion items were also a problem (45% DIF). The main reasons for DIF were changes in word difficulty, changes in item format, differences in cultural relevance, and changes in content.