The Impact of the 2021 Thrifty Food Plan Update on Food Insecurity: Evidence from State-Level SNAP Participation and Purchasing Power

Abstract

This paper examines the impact of the 2021 Thrifty Food Plan (TFP) re-evaluation on food insecurity in the United States. The reform increased maximum Supplemental Nutrition Assistance Program (SNAP) benefits by approximately 21 percent relative to pre-pandemic levels and represents the first permanent adjustment to benefit adequacy in decades. Despite its scale, there is limited empirical evidence on how such structural increases in benefit generosity affect food insecurity over time. Using a state-level panel dataset from 2016 to 2023, this paper implements a difference-in-differences framework with continuous treatment intensity, exploiting variation in pre-policy SNAP participation rates across states. This approach enables identification despite the nationwide implementation of the policy. The analysis also incorporates regional price parities to examine how cost-of-living differences shape the effectiveness of benefit increases. The results indicate that the 2021 TFP update is associated with reductions in food insecurity in states with higher SNAP participation, with larger and more precisely estimated effects for child food insecurity. In contrast, effects on overall food insecurity are smaller and less consistently significant across specifications. Additional analyses provide limited evidence that cost-of-living differences systematically alter the policy’s effectiveness. These findings suggest that permanent increases in SNAP benefit generosity can improve food security, particularly for more vulnerable populations, but may not generate uniform effects across all households. More broadly, the results highlight the importance of program exposure in shaping policy outcomes and contribute new evidence on the effects of a structural reform to SNAP.