Defining and Applying Age-Specific Retention Measures Among Infants and Children in the WIC Program

Purpose Assessing continued participation in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) is challenging due to the lack of standardized retention measures. We propose child-level retention and engagement metrics and demonstrate their application in evaluating associations between a specific WIC policy change—the increase in the cash-value benefit (CVB)—and retention . Design Longitudinal observational study. Setting Administrative data (March 2019–December 2023) from a tribal WIC state agency. Sample 5,794 WIC participants enrolled as infants (0–11 months). Measures Three measures were constructed: (1) age-specific retention (2) a summary retention ratio, capturing participation over the entire eligibility period, and (3) an engagement measure based on household benefit redemption during certification periods. Analysis Cross-tabulations and t-tests were used to analyze retention and engagement. Logistic regression models estimated the odds of retention following the CVB policy change. Results Retention ranged from 63–72% across age groups. Retained participants redeemed benefits more frequently than non-retained participants during their prior certification period. Among children with full follow-up, 34% completed all eligible certifications. After CVB increase, retention from infancy to age one was four percentage points higher ( P = .026). Conclusion The proposed measures provide a practical framework for monitoring WIC retention and engagement and for examining changes over time, including in relation to policy changes.