What Can We Learn about the Effects of Food Stamps on Obesity in the Presence of Misreporting?

There is an increasing perception among policy makers that food stamp benefits contribute positively to adult obesity rates. We show that these results are heavily dependent on one's assumptions regarding the accuracy of reported food stamp participation. When allowing for misreporting, we find no evidence that Supplemental Nutrition Assistance Program participation significantly increases the probability of being obese or overweight among adults. Our results also highlight the inherent bias and inconsistency of common point estimates when ignoring misreporting, with treatment effects from instrumental variable methods exceeding the nonparametric upper bounds by over 200% in some cases.