From 2015-2021, Root Cause was the third-party evaluator that reviewed data and validated program performance for the nation's first Pay for Success initiative designed to reduce chronic and long-term homelessness among adults. Massachusetts' Alliance for Supportive Housing's Pay-for-Success program significantly exceeded its targets, successfully placing over 1,055 high-need individuals into stable, supportive housing, with 85% retaining housing or transitioning to an appropriate care setting.