Functional analysis methodology: Some closing comments.

Functional analysis methodologies have emerged as powerful tools in research on the assessment and treatment of severe behavior disorders. Although the defining feature of these approaches is the systematic identification of environmental determinants of behavior, research methodology has varied widely with respect to the arrangements used to demonstrate experimental control as well as the types of variables subject to analysis. This commentary summarizes methodological and conceptual issues that have been raised in current research and offers some suggestions for their resolution.