Can targeted transfers improve birth outcomes? Evidence from the introduction of the WIC program

The goal of federal food and nutrition programs in the United States is to improve the nutritional well-being and health of low income families. A large body of literature evaluates the extent to which the Supplemental Program for Women Infants and Children (WIC) has accomplished this goal, but most studies have been based on research designs that compare program participants to non-participants. If selection into these programs is non-random then such comparisons will lead to biased estimates of the program's true effects. In this study we use the rollout of the WIC program across counties to estimate the impact of the program on infant health. We find that the implementation of WIC led to an increase in average birth weight and a decrease in the fraction of births that are classified as low birth weight. We find no evidence that these estimates are driven by changes in fertility or selection into live births. Our preferred estimates suggest that WIC initiation raised average birth weight by 2 g, or by 7 g among infants born to mothers with low education levels. These translate into estimated birth weight increases among participating mothers of approximately 18 to 29g. Estimated treatments on the treated impacts among infants born to participating mothers with low education are of similar magnitude. (C) 2010 Elsevier B.V. All rights reserved.