From this month’s Assessing the Evidence Base Series reviews, we learn that most residential treatment and recovery housing programs are “challenged by a lack of a clear definition of service methods, treatment duration, and treatment standards.” The same can also be said for the innumerable group homes, board-and-care homes, adult homes, and other forms of not-well-defined or regulated congregate housing used in most states as permanent housing for people with mental illness. Among this assortment of programs, permanent supportive housing is one model that provides clearly defined program fidelity standards. These standards reflect critical program features and underlying philosophies that have consistently produced significantly better housing and treatment outcomes. The standards provide guidance on principles and structure and yet are flexible enough to accommodate local adaptations for various populations and cultural and geographic contexts. The challenge now becomes how to transform the practice of the many existing programs and to help them adopt the standards of permanent supportive housing and Housing First.