Guidance for conducting feasibility and pilot studies for implementation trials

Background: Implementation trials aim to test the effects of implementation strategies on the adoption, integration or uptake of an evidence-based intervention within organisations or settings. Feasibility and pilot studies can assist with building and testing effective implementation strategies by helping to address uncertainties around design and methods, assessing potential implementation strategy effects and identifying potential causal mechanisms. This paper aims to provide broad guidance for the conduct of feasibility and pilot studies for implementation trials. Methods: We convened a group with a mutual interest in the use of feasibility and pilot trials in implementation science including implementation and behavioural science experts and public health researchers. We conducted a literature review to identify existing recommendations for feasibility and pilot studies, as well as publications describing formative processes for implementation trials. In the absence of previous explicit guidance for the conduct of feasibility or pilot implementation trials specifically, we used the effectiveness-implementation hybrid trial design typology proposed by Curran and colleagues as a framework for conceptualising the application of feasibility and pilot testing of implementation interventions. We discuss and offer guidance regarding the aims, methods, design, measures, progression criteria and reporting for implementation feasibility and pilot studies. Conclusions: This paper provides a resource for those undertaking preliminary work to enrich and inform larger scale implementation trials.