The Personal Responsibility and Work Opportunity Reconciliation Act of 1996 replaced Aid to Families with Dependent Children (AFDC) with block grants to states, called Temporary Assistance for Needy Families (TANF). Consistent with TANF's philosophy and goals, Los Angeles Jobs-First GAIN (Greater Avenues for Independence) emphasized job search assistance and imparted a strong pro-work message to move thousands of AFDC/TANF recipients quickly into jobs and off welfare. Central to the Jobs-First GAIN evaluation was an experimental design based on random assignment. Nearly 21,000 single parents and members of 2-parent households were randomly assigned to experimental and control groups. Experimental group members had access to Jobs-First GAIN's program services and Work First message. Control group members were precluded from receiving Jobs-First GAIN services until the end of the followup period for the evaluation. Main findings were as follows: Jobs-First GAIN produced a substantial initial boost in employment and earnings; produced small reductions in welfare and food stamp receipt, but larger decreases in expenditures for public assistance; helped welfare recipients replace welfare dollars with earnings, though their overall income remained about the same; achieved larger employment and earnings gains than the county's previous, basic-education-focused program; and produced positive effects for many different types of welfare recipients. (Contains 42 references, 38 tables, and 12 figures.) (YLB)