This chapter reviews recent theory and empirical evidence regarding the effect of SNAP on food insecurity and replicates the modelling strategies used in the empirical literature. The authors find that recent evidence suggesting an ameliorative effect of SNAP on food insecurity may not be robust to specification choice or data. Most specifications mirror the existing literature in finding a positive association of food insecurity with SNAP participation. Two-stage least squares and control function methods do show that SNAP reduces food insecurity, but effects are not consistent across sub-populations and are not always statistically significant.