Variation in the Heritability of Educational Attainment: An International Meta-Analysis

To assess heterogeneity in the influence of genetic variation on educational attainment across environmental contexts, we present a meta-analysis of heritability estimates in fifteen samples and thirty-four subgroups differing by nationality, sex, and birth cohort. We find that heritability, shared environment, and unshared environment each explain a substantial percentage of the variance in attainment across all countries, with between-sample heterogeneity in all three variance components. Although we observe only meager differences in the total family effect by cohort or sex, we observe large cohort and sex differences in the composition of the family effect, consistent with a history of higher heritability of educational attainment for males and for individuals born in the latter half of the twentieth century. Heritability also varies significantly by nation, with the direction of variation specific by sample. We find a markedly larger impact of shared environment on attainment than has been found for other social outcomes, with the percent of variation in attainment attributable to shared environment exceeding the percent attributable to heritability in one-third of the studies in our sample. Our findings demonstrate the heritability of educational attainment to be environmentally contingent, affirm the widespread and enduring role of shared environment in determining ultimate socioeconomic attainment, and emphasize the importance of considering behavioral genetics techniques in models of social mobility.