The Tradeoff between Family Size and Child Health in the United States
Posted: 28 Jun 2007
A great deal of work has been devoted to examining the relationship between family size (i.e., number of siblings) and child outcomes such as educational attainment and intellectual development. However, comparatively few published studies have investigated the relationship between family size and child health, none of which treated family size as endogenous.
Using data from the first two waves of the National Longitudinal Study of Adolescent Health, this research examines the relationship between family size and child health in the United States, and explores the mechanisms through which family size might affect child health. Throughout the analysis we pay special attention to the fact that parents choose the number of children they wish to have, and that this choice is potentially correlated with (from the standpoint of the researcher) unobservable confounders. Following work by Angrist, Lavy and Schlosser (2005), we restrict our sample to first- and second-borns, and use twin births and the sex composition of the first two children to identify exogenous variation in family size.
Ordinary least squares results suggest that family size is negatively related to many of our health indicators. In contrast, when family size is treated as an endogenous variable, its estimated effects often shrink in absolute magnitude and become statistically insignificant. This pattern of results is inconsistent with the predictions of the quantity-quality model first proposed by Becker(1960).
Angrist, Joshua D., Victor Lavy, and Analia Schlosser. 2005. "New Evidence on the Causal Link between the Quantity and Quality of Children." NBER Working Paper No. 11835.
Becker, Gary S. 1960. "An Economic Analysis of Fertility." In Demographic and Economic Change in Developed Countries (Princeton NJ: Princeton University Press), pp. 209-240.
Keywords: Adolescent Health, Family Size, Birth Order
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