Introduction for the special issue on functional assessment and treatment development.

The literature on functional assessment and function-based treatments is robust. Since the seminal articles published by Carr (1977) and Iwata Dorsey, Slifer, Bauman & Richard, (1982/1994), the field of functional analysis not only flourished, but it has revolutionized the assessment and treatment process. Functional assessment procedures have been used to guide the treatment process for a wide range of behavioral difficulties, including, aggression, self-injurious behavior, disruption, property destruction, ritualistic behavior, feeding disorders, pica to name a few. This literature has consistently shown that understanding why challenging behavior occurs is far more important than what it looks like to develop effective interventions. Prior to this research, treatments for problem behavior were often selected arbitrarily, without knowledge of the cause, which ultimately led to less effective, non-function based interventions (Carr & Durand, 1985; Durand & Kishi, 1987; Kahng, Iwata & Lewin, 2002; Repp, Felce & Barton, 1988). The importance of this body of literature cannot be underestimated. The literature has had a tremendous impact on clinical practice as we currently know it. Not only have functional assessment and treatment procedures been shown to benefit individuals exhibiting problem behavior (see Hanley, Iwata & McCord, 2003 and Kahng, et al., 2002 for reviews on the topic), but the model of evidence-based practice employed by practitioners using the procedures has influenced federal and state legislation regarding best practice (IDEA, 1997, 2004). While the literature on functional assessment and intervention development has changed the landscape of the educational system, gaps still remain in the translation of research to practice. Although these procedures have widespread support in the behavioral literature, they are often inconsistently applied in clinical settings. Some of these gaps are related to the use of empirically supported functional assessment procedures. Other gaps are related to treatment issues in applied settings. The current issue of Behavior Analyst Today will address some of these gaps in the literature related to the translation from empirical evidence to clinical practice. There remain questions about the practical application of functional assessment procedures. The article by Delfs and Campbell (2010) provides a unique quantitative review of the empirical literature on the topic of functional assessment. The authors discuss the validity of different types of functional behavioral assessment as well as the use of the procedures to determine if behavioral function and treatment effectiveness varies as a function of diagnosis. Sloman (2010) outlines critical issues as they relate to the use of descriptive assessment. While research findings have been mixed regarding the validity, the author reviews the circumstances under which descriptive assessment may be most useful. In addition, Sloman identifies novel uses of descriptive assessment procedures that may be useful for monitoring treatment integrity and providing feedback on implementation. In the paper by Manente, Maraventano, LaRue Delmolino & Sloan (2010), the authors review best practices in the assessment and treatment of adults with autism. They identify some of the unique challenges to the implementation functional assessment procedures and identify procedural modifications to facilitate their use in applied settings. Gadaire, Kelley, & DeRosa (2010) address one of the most glaring issues in the functional assessment and treatment literature at this time. Although the principles of operant behavior apply across diagnostic boundaries, the majority of behavioral assessment and treatment literature has focused exclusively on younger populations with developmental disabilities. As a result, best practice is often only extended to this population, and the extent to which other populations have benefitted from the advances in our science is limited. …