How Large Are the Effects from Changes in Family Environment? A Study of Korean American Adoptees

1,690 adoptees + 1,196 biological children across 1,114 families

Korean-American adoptees assigned to families quasi-randomly through the Holt agency queue.

Quasi-random assignment of children to adoptive families — a rare natural experiment separating nurture from genetic transmission.

Roughly three-quarters of ordinary parent-to-child transmission of educational attainment is NOT causal rearing. Family environment does move attainment (+7pp) — a real effect — but far less than the raw parent-child correlation implies. Behaviours like drinking and smoking transmit environmentally MORE strongly than attainment does.

Assignment to higher- vs lower-education adoptive families, benchmarked against biological-child transmission in the same families.

Quasi-random assignment removes the usual selection; the adoptee/biological contrast IS the estimate of nurture versus heredity.

Consistent with the broader adoption literature.