An important knowledge gap exists with respect to the role that housing assistance plays in promoting economic self-sufficiency among welfare recipients.  To fill this gap, Congress appropriated funds for Section 8 tenant-based assistance to help families make the transition from welfare to work. Abt Global conducted a congressionally mandated evaluation of this program for the U.S. Department of Housing and Urban Development (HUD) in 2004.  The randomized experiment provided evidence of the extent to which offering tenant-based rental assistance to low-income families not only met their immediate housing needs but may also, over the long term, increase their effective work effort by helping them move to where the jobs are and to find and keep employment. To conduct the experiment, Abt Global selected six evaluation sites, established site-specific procedures for conducting random assignment, collected administrative data on the sample members, and conducted in-depth in-person interviews with 75 program participants in the six sites.  Abt Global prepared the Report to Congress that provided an assessment of the impacts of receiving a Welfare to Work voucher on employment, earnings, receipt of welfare benefits, and housing location. In follow-on work, Abt Global developed a follow-up survey instrument and administered it to a sub-sample of the 8,732 individuals who were randomly assigned to the original research sample.  To measure the effects of vouchers, Abt Global tracked the families over a five-year followup period, and completed the final analysis of this extensive study.  The final report is avilable online through the HUD website.