Using data that enables us to distinguish between the different components of program participation (i.e., knowledge, application, and acceptance), we investigate the determinants of household behavior and program implementation in a social safety-net program that combines administrative and self-selection targeting methods. High undercoverage of eligible households primarily reflects lack of knowledge and binding budget constraints in poor areas. High leakage to ineligible households reflects the combination of their high levels of knowledge, application, and acceptance. Lowering undercoverage will require greater program awareness among the poor living in nonpoor areas and this is likely to come at the expense of substantial leakage to the nonpoor unless improvements are made to the verification process. Our results also suggest that in the presence of a budget constraint, the administrative selection process gives priority to the poorest households and those with children.