It’s More Than a Black Box; It’s a Russian Doll

Research on treatment efficacy and effectiveness requires that the treatments of interest be objectively defined. Such definitions are relatively straightforward for pharmacologic and surgical treatments, in which the active ingredients can be specified in terms of chemical structure or anatomic result. Definitions of treatment are more difficult for the many experience-based interventions employed in rehabilitation. This has led to the criticism that much clinical rehabilitation research has characterized the treatments of interest as a "black box," allowing little insight into the active ingredients contained therein. Moreover, rehabilitation care may involve the simultaneous application of multiple different treatments, raising the question of whether to define the individual components or the service delivery system. In this article, we consider how the levels of analysis considered in rehabilitation (disease, impairment, activity, and participation) and the role of theory shape the definition of treatment, and we address the need to develop protocol-based treatments and tools to objectively verify their contents. Rigorous definition of rehabilitation treatments, supported by theory, will facilitate needed efficacy research, will allow replication of that research, and will ultimately foster dissemination of effective treatments into clinical practice.