Effects of Federal Nutrition Program on Birth Outcomes

摘要

Using a nationally representative sample of the birth cohort of the Early Childhood Longitudinal Study, we examine the impact on birth outcomes of the largest federal nutrition program in the United States: Special Supplemental Nutrition Program for Women, Infants, and Children (WIC). By identifying a set of strong and valid instrumental variables for WIC participation, we are able to address the fundamental problem in the literature—selection bias. Similar to recent studies, we find that WIC does not affect average birth weight and average gestational week after correcting for selection bias using the instrumental variable method. However, WIC participation has significantly reduced the probability of very premature birth and (very) low birth weight after controlling selection bias by bivariate probit models. Our results indicate that rather than affecting the average outcomes, WIC is more effective for births that are at high risk. The potential benefits of WIC program can be realized by increasing its focus on more disadvantaged mothers.