The impact of long‐term participation in the supplemental nutrition assistance program on child obesity
利用工具变量法处理内生性，研究发现长期参与SNAP显著降低了5-11岁儿童及12-18岁男孩的BMI百分位和超重肥胖概率，但对12-18岁女孩无显著影响。
Participation in the Supplemental Nutrition Assistance Program (SNAP) reached an all-time high of 40.2 million persons in March 2010, which means the program affects a substantial fraction of Americans. A significant body of research has emerged suggesting that participation in SNAP increases the probability of being obese for adult women and has little effect on the probability for adult men. However, studies addressing the effects of participation on children have produced mixed results. This paper examines the effect of long-term SNAP participation on the Body Mass Index (BMI) percentile and probability of being overweight or obese for children ages 5-18 using data from the National Longitudinal Survey of Youth 1979 Children and Young Adults data set. An instrumental variables identification strategy that exploits exogenous variation in state-level program parameters, as well as state and federal expansions of the Earned Income Tax Credit (EITC), is used to address the endogeneity between SNAP participation and obesity. SNAP participation is found to significantly reduce BMI percentile and the probability of being overweight or obese for boys and girls ages 5-11 and boys ages 12-18. For girls ages 12-18, SNAP participation appears to have no significant effect on these outcomes.