Meta-Analysis of American Race Differences in Intelligence

Abstract

We present a meta-analysis of 139 U.S. studies (1918–2017; N = 400,000) examining racial differences in intelligence averages and distributions. Studies were included if they used representative U.S. samples, IQ tests with at least 3 subtests, reported White reference groups, and provided sufficient statistics to compute Cohen’s d. Studies were excluded if samples were unrepresentative (e.g., elites, college-only, selective cities), duplicated, lacked general ability differences, lacked within-group SDs, lacked a White comparison group, or relied on scholastic achievement tests. Random- and mixed-effects meta-analytic models were used to estimate racial means. With the White mean set to 100, averages were 82 (Black), 89 (Hispanic/American Indian), 105 (Asian), and 109 (Jewish). Evidence indicates small study effects inflated Black mean IQs. Variances and distributions were similar across races, and there is strong evidence against convergence in intelligence between Blacks and Whites in cohorts born after 1960.