ers in the environment and broad environmental reorganization and restructuring. Many of these features are implemented as standard practice in the comprehensive or focused behavioral programs reviewed above and in Chapter 12. The concept of positive behavioral interventions and supports represents a theoretical, scientific, and legal attempt to bring all aspects of these successful, positive interventions to bear on resolving behavior problems in children with autism or other disorders.
A total of 366 outcomes of positive behavioral interventions and supports were examined in a detailed review of applied behavioral analysis studies of persons with autistic spectrum disorders (10%), mental retardation (about 50%), or combined diagnoses of retardation and autism, frequently accompanied by additional diagnoses (e.g., seizure disorder, brain damage; about 40%) (Carr et al., 1999a). These outcomes included 168 outcomes for children from birth to age 12; they addressed problems of aggression, self-injurious behavior, property destruction, tantrums, and combinations of problem behaviors. The success rate (90% or greater reduction in problem behavior from baseline levels) across pooled outcomes was generally within 5 points of 50 percent of individuals, regardless of the type of intervention. Good maintenance rates were observed for a substantial majority of outcomes (68.7%, 63.6%, and 71.4% for 1–5 months, 6–12 months, and 13–24 months, respectively). Males and females scored equivalent successes.
A similar review of a differently defined, overlapping data set (Horner et al., 2000) concluded that the available interventions are reasonably effective at reducing problem behaviors of persons with developmental disabilities, including autistic spectrum disorders. Reductions of 80 percent or greater were reported in one-half to two-thirds of the comparisons. Some reductions of 90 percent or greater were reported for individuals with all diagnostic labels and all classes of problem behaviors. The lowest success rate (23.5 percent) was for interventions that targeted sensory functions, compared with approximately 60 percent success rates for interventions based on functional behavioral assessments that identified other functions of problem behaviors (e.g., attention, escape, tangible, or multiple types).
A review of applied behavioral analysis interventions specifically for children with autistic spectrum disorders from birth to age 8 (Horner et al., 2000) addressed problems of tantrums, aggression, stereotypy, and self-injury. This targeted review found, for 37 comparisons, mean rates of reduction in problem behaviors of 85 percent (with a median reduction level of 93.2% and a mode of 100%). Fifty-nine percent of the comparisons recorded problem behavior reductions of 90 percent or greater, and 68 percent of the comparisons reported reductions of 80 percent or greater. The mean length of maintenance (assessed in 57% of studies; rates main-