Investigating Treatment Effects of Participating Jointly in SNAP and WIC when the Treatment Is Validated Only for SNAP

Abstract

The U.S. Department of Agriculture operates several food assistance programs aimed at alleviating food insecurity. We study whether participation in both participation in both SNAP and WIC alleviates food insecurity compared with participation in SNAP alone. We bound underlying causal effects by applying nonparametric treatment effect methods that allow for endogenous selection and underreported program participation when validation data are available for one program (treatment) but not the other. We estimate average treatment effects using data from the National Household Food Acquisition and Purchase Survey (FoodAPS). FoodAPS includes administrative data to validate SNAP participation. Information on local food prices allows us to construct a food expenditure‐based monotone instrumental variable that does not require a typical instrumental variable exclusion restriction. Under relatively weak monotonicity assumptions, we identify that the impact of participating in both programs relative to SNAP alone is strictly positive, suggesting that the programs are nonredundant. This evidence can support improved design and targeting of food programs.

Regional differences in the impact of the COVID-19 pandemic on food sufficiency in California, April–July 2020: implications for food programmes and policies

“…Other scholars have observed that simultaneous participation in federal nutrition programs, such as WIC and SNAP, is associated with lower risk of household food insecurity. (23) Differences in the implementation of these two programs, for example, in outreach activities or in the application process may explain varying coverage rates (defined as the percent of those eligible who are enrolled in the program).…”

Food Access, Program Participation, and Health: Research Using FoodAPS

“…All consider the impact of SNAP, and several add analysis of the school meals programs or WIC. Jensen, Kreider, and Zhylyeskyy (2019) look at various assumptions about misreporting of WIC and SNAP together in a setting-FoodAPS-where only one program's self-reports are validated with administrative data. This extends other work by Brent Kreider and a host of other coauthors looking at set identification and bounding of causal effects in settings with endogenous selection and misclassification.…”

Does Supplemental Nutrition Assistance Program Reduce Food Insecurity among Households with Children? Evidence from the Current Population Survey

“…A few studies conclude that SNAP participation alleviates food insecurity to some degree [ 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. Although most existing studies use data from household surveys which are subject to reporting errors [ 20 , 21 ], a recent study suggests that the degree of reporting error is small and yields relatively little effect on the estimated impact of SNAP participation on food insecurity [ 21 ].…”