(OR27-05-26) Impacts of California’s WIC Modernization Efforts on Participant Enrollment and Benefit Redemption: A Staggered Difference-in-Differences Design

Objectives: The Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) in California has among the highest participation rates (62.6%) of eligible individuals in the country (2018). However, there remains potential to improve the program’s reach. This study aimed to determine the impacts of California’s WIC statewide rollout of electronic benefit transfer (EBT) cards, the California WIC app, and WIC WISE (allowing for electronic benefit loading) on participant enrollment and benefit redemption prior to COVID-19.

Methods: This study used a quasi-experimental difference-in-differences design with publicly available longitudinal administrative data from California Health and Human Services on county by month outcomes. The rollout was administratively determined and occurred in staggered waves of counties from June 2019 to March 2020. Data for this study spanned 56 counties observed monthly from Jan. 2010 to Feb. 2020. Primary outcomes included changes in log-transformed county enrollment and county redemption dollars per family. The Callaway and Sant’Anna method was used to account for the staggered rollout design. As a sensitivity analysis, two placebo outcomes were tested: county unemployment rates and the number of Supplemental Nutrition Assistance Program (SNAP) households.

Results: A total of 98.2% of county-month observations had complete enrollment data, and 93.6% had complete redemption data. Significant increases in WIC enrollment were observed at 5mo (6.2%, [95% CI: 0.1%,12.7%]), 6mo (6.0%, [3.4%,8.8%]), and 7mo (10.4%, [8.1%,12.8%]) after rollout, but not from 1-4mo after rollout. No significant changes were observed with county redemption-per-family. The rollout had minimal correlation with changes in unemployment rate (-0.6%, [-1.1%, -0.1%]) and no correlation with changes in the number of SNAP households..

Conclusions: These findings suggest California’s WIC modernization efforts likely contributed to increased county enrollment in the months following implementation, though changes in redemption were not observed. Technological improvements within the WIC program may help retain existing participants and attract enrollees.

Funding Sources: Schwall Fellowship, Lurie Graduate Award, Big Bang Theory Fellowship