DETECTION OF GENDER-RELATED DIFFERENTIAL ITEM FUNCTIONING IN A MATHEMATICS PERFORMANCE ASSESSMENT

This study used three different differential item functioning (DIF) de tection procedures to examine the extent to which items in a mathemati cs performance assessment functioned differently for matched gender gr oups. In addition to examining the appropriateness of individual items in terms of DIF with respect to gender, an attempt was made to identi fy factors (e.g., content, cognitive processes, differences in ability distributions, etc.) that may be related to DIF. The QUASAR (Quantita tive Understanding: Amplifying Student Achievement and Reasoning) Cogn itive Assessment Instrument (QCAI) is designed to measure students' ma thematical thinking and reasoning skills and consists of open-ended it ems that require students to show their solution processes and provide explanations for their answers. In this study, 33 polytomously scored items, which were distributed within four test forms, were evaluated with respect to gender-related DIF. The data source was sixth- and sev enth-grade student responses to each of the four test forms administra ted in the spring of 1992 at all six school sites participating in the QUASAR project. The sample consisted of 1,782 students with approxima tely equal numbers of female and male students. The results indicated that DIF may not be serious for 31 of the 33 items (94%) in the QCAI. For the two items that were detected as functioning differently for ma le and female students, several plausible factors for DIF were discuss ed. The results from the secondary analyses, which removed the mutual influence of the two items, indicated that DIF in one item, PPP1, whic h favored female students rather than their matched male students, was of particular concern. These secondary analyses suggest that the dete ction of DIF in the other item in the original analysis may have been due to the influence of Item PPP1 because they were both in the same t est form.