On September 22 and 23, 2016, OPRE brought together a diverse group of participants from federal agencies, research firms, foundations, and academia to discuss these issues. Participants explored alternatives to RCTs and their assumptions, trade-offs, benefits, and challenges. Specifically, the meeting addressed the following questions: 1. When is it appropriate to use alternatives to traditional RCTs? 2. What are some rigorous alternatives to traditional RCTs for assessing program impacts? 3. How have these alternatives been employed to strengthen the evidence base for social programs? 4. What are the next steps for the field? In this brief, we summarize key themes that emerged from the meeting. (author abstract)