Detection of Differential Item Functioning

Abstract

This study analyzes Differential Item Functioning (DIF) with three combined decision rules and compares the results with the variation of the Mantel-Haenszel procedure (vaMH) proposed by Mazor, Clauser, and Hambleton (1994). One decision rule combines the Mantel-Haenszel procedure (MH) with the Breslow-Day test of trend in odds ratio heterogeneity (BDT), having performed the Bonferroni adjustment, as Randall Penfield proposed. The second uses both MH and BDT without the Bonferroni adjustment. The third combines MH with the Breslow-Day test for homogeneity of the odds ratio without the Bonferroni adjustment. The three decision rules yielded satisfactory results, showed similar power, and none of them detected DIF erroneously. The second rule proved to be the most powerful in the presence of nonuniform DIF. Only in the presence of uniform DIF with the smallest difference of difficulty parameters, was there evidence of vaMH’s superiority.