Research completed since the 1980s has yielded substantial knowledge about how to help welfare recipients and other low-income individuals prepare for and find jobs. Many participants in these successful job preparation and placement programs, however, ended up in unstable, low-paying jobs, and little was known about how to effectively help them keep employment and advance in their jobs. The national Employment Retention and Advancement (ERA) project sought to fill this knowledge gap, by examining over a dozen innovative and diverse employment retention and advancement models developed by states and localities for different target groups, to determine whether effective strategies could be identified. Using a random assignment research design, the ERA project tested the effectiveness of programs that attempted to promote steady work and career advancement for current and former welfare recipients and other low-wage workers, most of whom were single mothers. The programs--generally supported by existing public funding, not special demonstration grants--reflected state and local choices regarding target populations, goals, ways of providing services, and staffing. The ERA project is being conducted by MDRC, under contract to the Administration for Children and Families (ACF) in the U.S. Department of Health and Human Services, with additional funding from the U.S. Department of Labor. This report presents the final effectiveness findings, or impacts, for 12 of the 16 ERA programs, and it also summarizes how the 12 programs were implemented and individuals' levels of participation in program services. Key findings include: (1) Out of the twelve programs included in the report, three ERA programs produced positive economic impacts; nine did not; and (2) Increases in participation beyond control group levels were not consistent or large, which may have made it difficult for the programs to achieve impacts on employment retention and advancement. Before the ERA project began, there was not much evidence about the types of programs that could improve employment retention and advancement outcomes for current or former welfare recipients. The ERA evaluation provides valuable insights about the nature of retention and advancement problems and it underscores a number of key implementation challenges that a program would have to address. In addition, it reveals shortcomings in a range of common approaches now in use, while identifying three distinct approaches that seem promising and worthy of further exploration. Appendices include: (1) Supplementary Exhibits for Chapter 3: Programs Serving Unemployed TANF Recipients; (2) Supplementary Exhibits for Chapter 4: Programs Serving Employed TANF Recipients; (3) Supplementary Exhibits for Chapter 5: Programs Serving Employed Non-TANF Recipients; (4) Exhibits Showing Additional Outcomes from the 42-Month Survey and the 42-Month Survey Response Analysis; (5) Site-Specific Publications for the Employment Retention and Advancement (ERA) Project Tests Discussed in This Report. Individual chapters contain footnotes. (Contains 145 tables, 9 figures, 20 boxes and 11 charts.) [This paper was written with the assistance of Aaron Hill and Sonya Williams. For the executive summary, see ED514700.]