The homogeneity assumption in differential prediction analysis: Does it really matter?

In simulation studies, the F test for differences in regression slopes has tended to distort nominal Type I and II error rates when the 2 subgroup err or variances exceeded a 1.50:1 ratio. This study examines the frequency and extent that this ratio is violated within data sets relevant to applied ps ychology. The General Aptitude Test Battery (GATB) validity study database contained ability data and overall job performance ratings. The Project A m ilitary database contained both ability and personality data, along with jo b performance factor scores and an overall job performance rating. Results suggest that subgroup (White-Black, male-female) error variances are often homogeneous enough to support F test results from past empirical work. Enou gh heterogeneity was found, however, to urge applied psychologists investig ating differential prediction to explore their data and consider the possib ility of alternative statistical tests.