Do School Lunches Contribute to Childhood Obesity?
利用面板数据和断点回归设计，评估美国国家学校午餐计划对儿童肥胖的因果影响，发现吃学校午餐的儿童肥胖率比自带午餐者高约2个百分点。
The most recent figures show that 16 percent of children aged 6-11 are obese – almost twice the rate of overweight in the early 1980s. Although there are few straightforward policy tools to combat the high level of obesity, almost two thirds of school children eat a National School Lunch Program lunch, and consume about one-third of their total calories from this meal. Previous studies have established that the school lunch program lunches often fail to meet nutrition requirements, and have an especially high fat content. In this project, I assess whether the National School Lunch Program plays a role in the incidence of childhood obesity. I employ two methods to isolate the causal impact of school lunches on childhood overweight. First, using panel data from the Early Childhood Longitudinal Survey I find that children who consume school lunches are about 2 percentile points more likely to be obese than those who brown bag their lunches. But since both groups of children enter kindergarten with the same obesity rates, the panel data suggests that the difference in obesity rates is not merely a function of fixed differences between children who select into the school lunch program. Second, I leverage the sharp discontinuity in eligibility for reduced-price lunch – available to