Coding ProceduresAn abstracting protocol was used to code the researchdesign, sample size, subject characteristics, outcomesreported, direction and magnitude of the findings, andthe assessment instruments used. Adaptive behavior out-comes were summarized in eight domains: overall adap-tive behavior and seven subdomains, including academicskills, community living skills, language/communicationskills, motor/physical skills, self-care/domestic skills,social skills, and vocational skills. Challenging behavioroutcomes were summarized in three domains: overallchallenging behavior, externally focused behavior (e.g.,aggression, property damage), and internally focusedbehavior (e.g., withdrawal, self-injury).