This working paper was prepared by Leighton Ku and Robert Dalrymple, Office of Analysis and Evaluation, Food and Nutrition Service, U.S. Department of Agriculture. The paper notes differences between SIPP and FNS program data on child nutrition programs and WIC. It is designed to help users of SIPP data to understand and interpret selected program data in the SIPP. It also suggests how the survey editing and imputation may bias analyses of these programs. The following topics are discussed: