Access to the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) at the State and Substate Levels: Meaning and Measurement

This study estimates eligibility and access rates for the U.S. Department of Agriculture’s (USDA) Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) using micro-level WIC administrative data linked with American Community Survey (ACS) data. This study is one result of a long-term research collaboration among USDA’s Economic Research Service; the U.S. Department of Commerce, Bureau of the Census; USDA’s Food and Nutrition Service (FNS); and participating State WIC agencies. By analyzing WIC participation at the State and substate levels, the report provides insights into program reach and demographic differences. The findings confirm that the Census Bureau estimates meet high statistical reliability standards, providing valuable data for program officials, managers, and other stakeholders to enhance program outreach and effectiveness. A key focus of the report is the comparison between Census Bureau and USDA, FNS estimates, which differ in methodology and measurement scope. Using data from the Arizona Department of Health Services for a case study, the analysis finds that Census Bureau estimates of WIC access rates for infants and children vary widely across Arizona counties, ranging from about 13.3 percent to 79.0 percent. The relatively low access rates of some counties reflect how a large proportion of their WIC clients may access the program through an Indian Tribal Organization, in which case their participation is not recorded in data of the Arizona Department of Health Services.