This paper investigates dynamic patterns in the relationship between eligibility and participation in the Aid to Families with Dependent Children (AFDC) and Food Stamp programs, using monthly longitudinal data from the Survey of Income and Program Participation. Tile result's indicate that there are many relatively short eligibility spells that do not result in program participation, and end with increases in income. Participation is most likely to occur among women with lower current and future earnings opportunities, and is affected by locational and policy parameters. Those who elect to participate in these programs tend to start receiving benefits almost immediately upon becoming eligible. A substantial number of women exit these programs before their eligibility ends; among at least some of these women it is likely that unreported changes in income are occurring. In 1989, if all eligible single-parent families had participated in AFDC and Food Stamps, benefit payments in these programs would have been $13.5 billion higher.
