Creating Policy Relevant Evidence: Rationale and Overall Design of the At Home/Chez Soi Demonstration Project

Introduction: Housing First is a complex intervention with sufficient knowledge base and interest to warrant a test of wide-scale implementation in various settings. The design and implementation of a Canadian 5 city, $110 million demonstration project illustrates how the evaluation of a complex health services intervention can address rigor and relevance. Objective: To describe the overall project design and the rationale for key scientific and operational decisions regarding the first and only multi-site trial of Housing First. Methods: The multi-level core study tests the feasibility, effectiveness and costs of implementing Housing First programs in varied contexts. It will randomize 1600 participants who are homeless and have a mental illness into treatment as usual or two intervention arms, Housing First plus Assertive Community Treatment for those with high needs and Housing First plus Intensive Case Management for those with moderate needs. An adaptation in one mid-size city with 200 participants will have one Housing First intervention arm in a combined need group. A common mixed-methods protocol includes assessments every six months over two years of follow-up. Discussion: In 18 months this large trial was planned and implemented to generate knowledge that would be credible and relevant. A participatory approach that sought and used the advice of various groups created unique challenges but also informed decisions in a positive manner. A hybrid multi-site structure that combines a common set of questions and measures with local city adaptations has proven to be feasible albeit challenging.