A pound of flesh: The use of birthweight as a measure of human capital endowment in economics research

Birthweight is increasingly being used by economists and other social scientists to measure health endowment at birth. Research in this tradition has evolved from regression analysis to twin difference models to natural experiment approaches that use such events as natural disasters to capture the effects of fetal nutrition and stress on this measure of neonatal health. Furthermore, causal inference approaches have been used to show that birthweight affects health, cognitive and noncognitive development, and educational achievement and attainment, as well as adult wages. An important recent line of literature investigates the heterogeneous impact of birthweight within and between families, examining such moderating factors as family resources, parental investment, and even genotype. This chapter discusses various methods (and their limitations) to incorporating birthweight into economic models as an outcome predictor or moderator.