Although the National School Lunch Program (NSLP) and the School Breakfast Program (SBP) help ensure that many low-income children have enough nutritious food to eat, some studies have suggested that the programs could be more efficient and cost-effective. In particular, concerns have been raised about erroneous payments that reimburse schools for meals served to students who are not eligible for them. Policymakers would also like to find ways to reduce errors that arise when schools and school districts process or report meal reimbursement information incorrectly. This brief draws on Mathematica's Access, Participation, Eligibility, and Certification (APEC) study to examine these issues. It provides the most detail to date on certification and payment errors in school meal programs. It suggests key factors for policymakers and program operators to consider as they move forward in developing initiatives for reducing payment errors. (Contains 2 figures.)