Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
Birth order effects are found in empirical work but lack solid theoretical foundations in economics. Our new modeling approach to children provides this. Each child’s needs change as it grows, and births are sequential. Each child has the same genetic makeup and parents do not favor one child over the other. Parental childcare time lowers the caregiver’s current and future wages; this opportunity cost varies across time. Benefits also vary and when parental childcare is a public input, coresident children allow economies of scope in childcare. Birth order effects emerge from the changing benefits and costs. (JEL D13, D91, J13)