Sandra
E. Black, Paul J. Devereux (UCLA) and Kjell G. Salvanes
ABSTRACT
Lower birth weight babies have worse
outcomes, both short-run in terms of one year mortality
rates and longer run in terms of educational attainment and
earnings. However, recent research has called into question
whether birth weight itself is important or whether it
simply reflects other hard-to-measure characteristics. By
applying within twin techniques using an unusually rich
dataset from Norway, we examine the effects of birth weight
on both short-run and long-run outcomes for the same
cohorts. We find that birth weight does matter; despite
short-run twin fixed effects estimates that are much smaller
than OLS estimates, the effects on longer-run outcomes such
as adult height, IQ, earnings, and education are significant
and similar in magnitude to OLS estimates.
