Marginal changes, marginal impacts: The limits of changes to WIC and their ability to influence breastfeeding rates

Abstract

We use restricted South Carolina natality data to investigate whether the 2009 revisions to the Special Supplemental Nutrition Program for Women, Infants and Children (WIC) food packages had a positive effect on breastfeeding initiation rates, a stated goal of the revisions. Usingadifference-in-difference methodologythat controls for separate trends in breastfeeding initiation rates between mothers who participate in WIC while pregnant with those who do not participate while pregnant, we estimate that the revisions had no statistically significant impacts on breastfeeding initiation. Although theseresults arenot consistent with much prior work, we also present estimates suggesting that these inconsistencies relative to the literature are the result of controlling for group specific trends and are not a unique artifact of our study setting or methodology.Our results suggest that the decision to breastfeed is relatively unresponsive with respect to marginal changes to existing programs, and that careful consideration of the appropriate empirical approach is paramount when evaluating program changes and drawing policy conclusions from research.