Coding ProceduresAn abstracting protocol was used to code the research design, sample size, subject characteristics, outcomes reported, direction and magnitude of the findings, and the assessment instruments used. Adaptive behavior outcomes were summarized in eight domains: overall adaptive behavior and seven subdomains, including academic skills, community living skills, language/communication skills, motor/physical skills, self-care domestic skills, social skills, and vocational skills. Challenging behavior outcomes were summarized in three domains: overall challenging behavior, externally focused behavior (e.g., aggression, property damage), and internally focused behavior (e.g., withdrawal, self-injury).