Distinguished Professor and Tyson Endowed Chair in food Policy Economics, University of Arkansas

This paper examines the effect of a very important government food assistance program in the US, the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC), on the quality of household food purchases using the US National Household Food Acquisition and Purchase Survey (FoodAPS). Purchase quality was measured using a healthy purchasing index (HPI). Findings using propensity score matching procedures indicate that WIC foods explain the improvement in quality of food purchases, not self-selection of more nutrition-conscious households into the program. Households participating in WIC have a higher HPI in comparison to eligible non-participating households. Importantly, this difference is driven entirely by WIC participating households who redeemed WIC foods during the interview week. There was no significant difference between WIC-participants who did not redeem WIC foods and eligible non-participants. The paper also examines whether geographic barriers limit WIC participation. Locations of WIC clinics were added to the already detailed FoodAPS information on food store locations. There is no evidence in this sample that access to clinics is adversely affecting participation nor is there evidence that HPI depends on supermarket access. Finally, a supervised machine learning process supports our main conclusion that WIC-provided foods are the driver of increased HPI, not self-selection of healthier households into the program.