The Frank Melville Supportive Housing Investment Act of 2010 introduced significant reforms to the Section 811 supportive housing for non-elderly adults with disabilities, including the new Section 811 Project Rental Assistance (PRA) Program and a mandated evaluation of its implementation and effectiveness. The Phase I is an implementation evaluation focused on the initial 18 months (Jan 2015-June 2016) of program implementation by the first 12 grantees funded through the Fiscal Year (FY) 2012 grant competition. It provides an overall picture of how the demonstration was implemented in the initial states and analyzes differences in program design, target population, and housing and service strategies. The overarching research questions include an assessment of the following aspects of program implementation: partnerships between state housing and health and human services or Medicaid agencies; property and unit selection strategies; target population outreach and referral approaches; supportive services availability; and major challenges and successes. Grantees spent much of the period covered by Phase I of the evaluation solidifying partner roles and responsibilities and developing the systems and procedures needed to accommodate this new and complex approach to providing affordable housing for people with disabilities. The pace of attracting properties and units to the program and leasing units has been slower than HUD and grantees expected for a variety of reasons, such as tight housing market conditions (high-price and low-vacancy), difficulty aligning housing and services, program requirements, and location mismatch. (Author abstract)