Exploring crossing differential item functioning by gender in mathematics assessment

The purpose of this article is to explore crossing differential item functioning (DIF) in a test drawn from a national examination of mathematics for 11-year-old pupils in England. An empirical dataset was analyzed to explore DIF by gender in a mathematics assessment. A two-step process involving the logistic regression (LR) procedure for detecting uniform and nonuniform DIF was applied to identify crossing DIF. The results showed 36 uniform and 19 nonuniform statistically significant gender DIF items. Out of the 19 nonuniform DIF items, 10 items were crossing DIF. We explained nonuniform DIF using the crossing point in item characteristic curves and the LR-DIF coding scheme. This study showed that crossing DIF exists in empirical data and the findings from this study provide a potentially valuable contribution in understanding such items.