Adjusting published twin-study ACE estimates for assortative mating raises mean heritability by about 17 points and lowers shared environmental estimates by about 16 points¶

Claim · All claims
Evidence · 1 study · associational r2 · q2
Currency · newest study 2023 · not yet checked against its sources · not reviewed by a person

Subclaims¶

q2 i? Re-analysis of 13 subgroups from the Branigan et al. meta-analysis that published parental or spousal correlations, using Martin's adjustment, shifted grand mean estimates from A = 38%, C = 39% to A = 55%, C = 23%. → Wolfram 2023

Evidence¶

Wolfram 2023¶

Wolfram, T. & Morris, D. (2023). Conventional twin studies overestimate the environmental differences between families relevant to educational attainment. npj Science of Learning 8, 24. https://doi.org/10.1038/s41539-023-00173-y

q2 · i? · associational · r2

Secondary re-analysis of a subsample of the Branigan et al. (2013) meta-analysis, applying Falconer's formulas and Martin's assortative-mating correction, then replicating the fixed-effects meta-analysis. The authors report "mean A estimates were 17 points higher and mean C estimates were 16 points lower".

"After adjusting for assortative mating, mean A estimates were 17 points higher and mean C estimates were 16 points lower."

Discussion¶

Related Claims¶

• The best-fitting NTFD model estimates heritability of educational attainment at 51% and total shared environmental influence at 26%, disaggregated into twin-specific (16%) and sibling-shared (10%) components — related
• Twin-specific shared environments account for a substantial portion of CTD shared-environment estimates for educational attainment and cannot be interpreted as between-family environmental differences — related
• A Classical Twin Design model of educational attainment in the TwinLife sample estimates shared environmental influence at 43% and additive genetic influence at 34% — related
• Under phenotypic assortment NTFD models, parental education shows no environmental effect on offspring educational attainment once genetic influences are accounted for — related
• Educational achievement is highly heritable, and the common environmental variance is attributable to SES effects — related
• Genetic and environmental variance components of educational achievement decrease with increasing parental SES — related