Researchers frequently rely on survey responses to determine whether families receive government assistance and to study the effects of government programs, but these responses are often inaccurate. This study investigates misreporting in the child-care subsidy program by comparing survey responses on child-care subsidy receipt with program administrative data in two states. While we find a lower rate of misreporting than is typical for other government assistance programs, overreporting of benefit receipt is surprisingly common and generates overestimates of program participation. Analyses further suggest that the frequency and systematic nature of misreporting bias estimates of the predictors of program receipt and the effects of the program. These findings illustrate the necessity of assessing the frequency of response errors and understanding their implications in generating valid research results on the effects of government programs. (author abstract)