Further Meta-Analytic Procedures for Assessing Cognitive Gender Differences

Abstract

We describe procedures for (a) assessing the heterogeneity of a set of effect sixes derived from a meta-analysis, (b) testing for trends by means of contrasts among the effect sizes obtained, and (c) evaluating the practical importance of the average effect size obtained. On the basis of applying these procedures to data presented in Hyde (1981) on cognitive gender differences, we conclude the following: (a) that for all four areas of cognitive skill investigated, effect sizes for gender differences differed significantly across studies (at least at p < .001); (b) that studies of gender differences conducted more recently show a substantial gain in cognitive performance by females relative to males (unweighted mean r across four cognitive areas = .40); (c) that studies of gender differences show male versus female effect sizes of practical importance equivalent to outcome rates of 60% versus 40%.