A Comparison between Some Generalized Mantel-Haenszel Statistics for Detecting DIF in Data Simulated under the Graded Response Model.

The main objective of this study was to establish the relative efficacy of the generalized Mantel-Haenszel test (GMH) and the Mantel test for detecting large numbers of differential item functioning (DIF) patterns. To this end this study considered a topic not dealt with in the literature to date: the possible differential effect of type of scores assigned to item-response categories on the power and Type I error rate of the Mantel test. For this purpose, a simulation study with data generated under the graded response model was carried out. The results showed that (a) the scoring system used to compute the Mantel test influences its power for detecting DIF and (b) for conditions comparable to those simulated, the GMH may be the best option, given that it is capable of detecting more complex patterns of association than the Mantel test, that is, more types of DIF.