SNAP participation, diet quality, and obesity: robust evidence with estimation techniques without external instrumental variables

This paper examines the effects of the Supplemental Nutrition Assistance Program (SNAP) on obesity among women. We address several of the empirical challenges surrounding the estimation of said effects raised in Currie and Moffitt (in: Moffitt RA, Moffitt R (eds) Means-tested transfer programs in the USA. University of Chicago Press, Chicago, 2003). We do so by employing a battery of recently developed econometric methods that require only cross-sectional data, and alternative identification assumptions relative to the traditional instrumental variable used in the current literature. Our goal is to assess whether the common findings are robust to various methods. Using data from the National Health and Nutrition Examination Survey, we reach two important conclusions. First, the positive effect of SNAP on both obesity and the body mass index is robust to differing statistical and modeling assumptions, while statistical significance may vary. Second, we also find that decreased dietary quality among SNAP participants could be at best a weak candidate for explaining the difference in our findings (if any) on obesity.