Ensuring treatment fidelity in intervention studies: Developing a checklist and scoring system within a behaviour change paradigm.

What is already known on this subject Treatment fidelity is an essential component of intervention effectiveness and efficacy studies, ensuring the intervention is delivered as intended. It is also an essential component of evidence-based clinical practice. However, few research studies report the treatment fidelity process or publish the checklists used, depriving clinicians of useful information for implementation. What this study adds This study describes in detail the iterative process of treatment fidelity checklist development, engaging those implementing the intervention in development. This ensured clarity and interrater reliability of the checklist. Furthermore, a novel scoring system was developed so that accuracy of implementation can be easily compared across users and across practice attempts. What are the clinical implications of this work? The importance of treatment fidelity when implementing effective and efficacious interventions cannot be overstated. The treatment fidelity checklist developed for research can be easily adopted to support accurate implementation in clinical practice through an audit process.