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A New Index of Differential Subgroup Performance: Application to the GRE Aptitude Test GRE GREB

Stricker, Lawrence J.
Publication Year:
Report Number:
ETS Research Report
Document Type:
Page Count:
Subject/Key Words:
Graduate Record Examinations Board, Aptitude Tests, Graduate Record Examinations (GRE), Item Analysis, Racial Differences, Sex Differences, Test Bias


The items on the GRE® Aptitude Test were analyzed for race (Black and White) and sex differences in their functioning, using three procedures for identifying items that perform differently: item partial correlations with subgroup membership (race or sex), controlling for total score; comparisons of item characteristic curves for subgroups; and plots of item difficulties for subgroups. All of these methods assume that the test is unidimensional and the total score (or the typical item) is relatively free of differential functioning and rely on internal analyses of the test to identify deviant items. Appreciable proportions of the items in each section of the test were identified as performing differentially for each race and sex by the partial correlation and ICC indexes, but only small proportions were identified by the item difficulty index. Although many items were identified by the two indexes, these measures were generally very small in magnitude, indicating that they detected a minimal degree of differential functioning.

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