Prevalence of Gender DIF in Mixed Format High School Exit Examinations.

The primary purpose of this study was to identify potential sources of gender differential item bias (DIF) in a high school exit examination composed of both selected-response and constructed-response items in the content areas of English, social studies, mathematics, and biology. A secondary purpose was to determine the agreement between the polytomous differential item functioning (DIF) detection methods, the Generalized Mantel-Haenszel (GMH) approach and Poly-Simultaneous Item Bias (Poly-SIB), and their counterparts, the Mantel-Haenszel procedure (MH) and SIB. Data were from four different Alberta Education Diploma Examinations for June and January 1998. The numbers of students that completed each form ranged from 2,328 to 3,386. Results indicate that both GMH and Poly-SIB were comparable to their dichotomous counterparts, MH and SIB, although there were slight differences between MH and GMH. Results about gender DIF support some hypotheses and not others. Males did not outperform females on geometry and mathematical problem solving items. Although more than 50 mathematics items were analyzed, only 8 dichotomous items were flagged. None of the gridded response items were flagged for DIF, and references to stereotypical male or female activities were not identified as DIF items or did not consistently favor one group or the other. While the majority of the dichotomous items favored males, all of the polytomous items favored females. These findings suggest that there may be an item-by-format interaction where females perform better on constructed response items even in measures of quantitative ability. The paper discusses some areas for future research. (Contains 10 tables, 1 figure, and 34 references.) (SLD)