Twenty years of applied behavior analysis in treating the most severe problem behavior: Lessons learned.

This paper reviews some of the author's experiences during the past 20 years of treating severe problem behavior. Factors that represent barriers to success are identified and discussed, as are factors that contribute to the development of successful treatment programs. Barriers to success include the inherent reactive nature of human services and educational systems, expertise problems, systems problems, information gaps, programming problems, characteristics of problem behavior, and maintenance problems. Some new programmatic directions are suggested for overcoming the various treatment barriers. The paper concludes with strategies and factors to consider that will ensure long-term success in the treatment of severe problem behavior.