The objective of the Community Choice Demonstration is to build rigorous evidence on how to advance the long-held goals of expanding residential choice and facilitating moves to opportunity areas by families with children participating in the Housing Choice Voucher (HCV) program. This rigorous multi-site experiment will test two types of interventions: comprehensive mobility-related services (CMRS) and a smaller bundle of selected mobility-related services (SMRS). The confirmatory research questions for the first phase of the Demonstration focus on the effects of being offered CMRS on the share of families who move to an opportunity area and the duration of residency in an opportunity area. The second phase of the Demonstration will examine the impacts of SMRS on these same outcomes as well as the contrast between CMRS and SMRS. The research design provides a blueprint for the study implementation, including: the elements of the intervention, the study’s implementation approach and support of PHAs in Phase 1, the mixed-methods evaluation strategy (including the Process, Impact, and Cost Studies), the preparations for Phase 2 research and beyond, and data security measures.