Sex differences in variability in the national norms of the Differential Aptitude Tests, Preliminary Scholastic Aptitude Test/Scholastic Aptitude Test, Wechsler Adult Intelligence Scales, and California Achievement Tests were examined. Compared to females, males were consistently more variable in quantitative reasoning, spatial visualization,…

The author's previous article was intended to demonstrate that research on intellective sex differences (SDs) was incomplete because of a general preoccupation with SDs in means. SDs in central tendency and SDs in variability must be considered together to comprehend differences between male and female distributions in abilities. (SLD)

Sex differences in variability of performance on cognitive tests were previously examined by calculating the ratios of males' variances to females' variances. Reasons why variance ratios were summarized by medians are discussed. (SLD)

The second approach used by L. V. Hedges and L. Friedman (1993) in their reanalysis of Feingold's earlier results is conceptually equivalent and yields results consistent with the original interpretation. The first method yields results that are discrepant. Analyses of variations in tail effect sizes are planned. (SLD)