Comparison of DIF Detection Methods

Differential item functioning (DIF) has been one of the important considerations in measurement practices over the last three decades. Various statistical methods have been developed to detect DIF, and as a result, many simulation studies have been conducted to evaluate the performance of two or three methods under different test situations. To have an overall picture on how they compare for tests with dichotomous items with and without DIF, this study carries out a comprehensive comparison of these methods by evaluating their type I error and power rates controlling for sample sizes, test lengths, DIF sizes, and DIF proportions. Results of the study provide a set of guidelines for researchers and practitioners on the use of each DIF detection method in different test situations where uniform or nonuniform DIF is present.