The Personal Responsibility and Work Opportunity Reconciliation Act of 1996 transformed the focus of welfare policy in the United States. Instead of the entitlement to cash assistance embodied in the Aid to Families with Dependent Children, Temporary Assistance to Needy Families (TANF) encourages economic self-sufficiency through employment. After five years, evidence is accumulating as to the policy's successes and failures. A key feature of this...