This study examined how much improvement was attainable with respect to accuracy of differential item functioning (DIF) measures and DIF detection rates in the Mantel-Haenszel procedure when employing focal and reference groups with notably unbalanced sample sizes where the focal group has a fixed small sample which does not satisfy the minimum…

Douglas, Roussos, and Stout introduced the concept of differential bundle functioning (DBF) for identifying the underlying causes of differential item functioning (DIF). In this study, reference group was simulated to have higher mean ability than the focal group on a nuisance dimension, resulting in DIF for each of the multidimensional items…

Performances of the Mantel Haenszel odds-ratio estimator and chi-square significance test were investigated using simulated data for 500 reference group and 500 focal group examinees. Results demonstrate the importance of using both the odds-ratio and significance tests in interpreting the presence or absence of differential item functioning. (SLD)