Examining sources of gender DIF in Mathematics knowledge of future teachers using cross-classified IRT models

Abstract

Research on differential item functioning (DIF) has focused traditionally on the detection of effects. However, recent studies have investigated potential sources of DIF, in an attempt to determine how or why it may occur. This study examines variability in item difficulty in math performance that is accounted for by gender, referred to as gender DIF, and the extent to which gender DIF is explained by both person predictors (opportunity to learn [OTL]) and item characteristics (item format). Cross-classified multilevel IRT models are used to examine the relationships among item difficulty, gender, OTL, and item format. Data come from the U.S. cohort of an international study of future math teachers, the Teacher Education and Development Study in Mathematics.