The Welfare, Children and Families Study is a longitudinal study of children and their caregivers in low- income families that were living in low-income neighborhoods in three cities in 1999. The purpose of the study is to investigate the consequences of policy changes resulting from the Personal Responsibility and Work Opportunity Reconciliation Act of 1996 (PRWORA)1. The survey was designed to provide information on the health and cognitive, behavioral, and emotional development of children and on their primary caregivers' labor force behavior, welfare experiences, family lives, use of social service, health, and well-being.