Intervention fidelity: a common language for clinicians and researchers

This paper explores the importance of fidelity in strengthening clinical translation and implementation of rehabilitation research interventions and in reducing unwarranted variation in practice patterns. Fidelity, or accurate and faithful delivery of an intervention, is critical for all aspects of the clinical translational research continuum. Fidelity intentionally defines and tracks the key or active ingredients of a research intervention, ensures adherence to and dose of these key ingredients across therapists and research sites, and clearly establishes what is new or different about an intervention as compared to usual or standard practice. Measurement and reporting standards for fidelity in rehabilitation research vary widely. Historically, rehabilitation researchers have not reported their fidelity process clearly, if at all. This reporting gap creates a multi-faceted conundrum for replication of research findings and eventual clinical implementation of rehabilitation interventions. Without clear fidelity metrics, researchers fail to establish what is novel or unique about an intervention and fail to differentiate a new intervention from other established approaches. Without seeking and applying fidelity metrics, clinicians have no way of replicating a new intervention or understanding which key ingredients replace or supersede old practice habits. Thus, failure of researchers to transparently communicate and of clinicians to understand and apply fidelity metrics widens unwarranted practice variations rather than improving our precision with rehabilitation interventions. Using 2 recent pediatric clinical trials as exemplars, we describe how the development and tracking of metrics defining fidelity for the Sitting Together and Reaching to Play (START-Play) intervention informed key ingredients and program differentiation as researchers moved from an efficacy to an effectiveness trial; and then propose how clinicians might use these same metrics to inform implementation of START-Play. This example will demonstrate how robust fidelity might serve as a common language for successful implementation of and improved precision with rehabilitation research interventions.