Family & Intergenerational

Within-family sibling analyses and mother–child cognitive transmission from CNLSY.

Intergenerational Transmission

Mother → Child gproxy Transmission

Standardized regression coefficient (β) for mother's gproxy predicting child's gproxy

Model N pairs βmother_g βparent_ed p R²
Bivariate 115 0.448 — < 0.001 0.232
SES-controlled 114 0.402 — < 0.001 0.230

Mother–child gproxy correlation is 0.45. Adding parental education reduces the coefficient by only 10% (0.448 → 0.402), indicating the transmission is largely independent of measured SES.

Sibling Fixed Effects

Education: Between vs Within Family (NLSY79)

Years of education per SD of gproxy

Earnings: Between vs Within Family (NLSY79)

Annual earnings ($) per SD of gproxy

Education: Between vs Within Family (NLSY97)

Years of education per SD of gproxy

Household Income: Between vs Within Family (NLSY97)

Household income ($) per SD of gproxy

Cohort Outcome N families N individuals βbetween βwithin pwithin R²within
NLSY79 Education (years) — — 1.63 2.10 < 0.001 —
NLSY79 Earnings ($) — — 8,524 8,734 < 0.001 —
NLSY97 Education (years) — — 1.83 1.42 < 0.001 —
NLSY97 Household income ($) — — 16,830 6,427 < 0.01 —

Within-family estimates — which control for all shared family factors — remain significant for education and earnings in NLSY79, confirming that cognitive differences predict outcomes even among siblings.

Sex-Specific Outcome Returns

Education Return by Sex

Years of education per SD of gproxy, by sex and cohort

Wage Return by Sex (NLSY79)

Annual earnings ($) per SD of gproxy, by sex

Cohort Outcome βmale βfemale p (difference)
NLSY79 Education (years) 1.66 1.78 0.024
NLSY97 Education (years) 1.80 2.30 < 0.001
NLSY79 Wages ($) 7,241 6,072 0.002

Females show stronger g → education associations in both cohorts. Males show stronger g → earnings returns in NLSY79.