Sibling Position and Achievement

Past studies linking schooling and career attainment to sibling position (family size, birth order, spacing) are vulnerable to suspicions about omitted variables: being based on cross-sections of individuals from different families, they may have attributed to sibling position an influence belonging to unobserved parental attributes. This study retests the link between sibling position and achievement, using a cross-section of intrafamily sibling differences. The alleged link is confirmed. Further, its pattern is very consistent with the view that sibling position matters because of its straightforward effects on family time and commodity inputs into children.