Guaranteeing that low-income children have enough to eat and consume the right mix of nutritious foods is the aim of the National School Lunch Program (NSLP) and the School Breakfast Program (SBP). These programs provide meals to children in almost all public schools as well as many private schools across the nation. On an average day in 2009, the NSLP and SBP served low-cost or free meals to 31.2 million and 11 million children, respectively. The NSLP also serves nutritious snacks to children participating in afterschool educational and enrichment programs.

Mathematica's SNDA-IV study examined the nutritional quality of meals and snacks offered and served to children in the NSLP and SBP. The study also assessed other issues related to school food environments and meal service operations, including policies about and availability of competitive foods (foods offered outside the school meal programs), school wellness policies, and food safety.

Data were collected between January and June 2010 from nationally representative samples of approximately 600 school food authorities and 900 schools primarily through mail and web-based surveys. Extensive telephone-based technical assistance was provided to school food service managers, who provided detailed data about foods offered and served in breakfasts, lunches, and afterschool snacks for a specific school week.

We also used data from the previous SNDA study, which Mathematica conducted, to identify characteristics of school meals and school meal environments that are associated with the nutritional quality of meals served and consumed. Our predictive models estimated the likely impact of changes in policy or practice on the nutritional quality of meals served and consumed, levels of student participation, and program costs.