Recommendations for progression criteria during external randomised pilot trial design, conduct, analysis and reporting

BACKGROUND: External randomised pilot trials aim to assess whether a future definitive Randomised Controlled Trial (RCT) is feasible. Prespecified progression criteria help guide the interpretation of pilot trial findings to decide whether, and how, a definitive RCT should be conducted. This commentary presents a set of proposed recommendations for progression criteria to guide researchers when (i) designing, (ii) conducting, (iii) analysing and (iv) reporting external randomised pilot trials. METHODS: Recommendations were developed following a mixed methods approach. This involved (i) a methodological review of pilot trial publications, (ii) a cross-sectional study of pilot trial research funding applications, (iii) qualitative interviews with pilot trial researchers and (iv) a survey of corresponding authors of identified pilot trial publications. Initial recommendations were refined following two consultation stakeholder workshops held in July 2022. Recommendations for progression criteria for external randomised pilot trials: i. Design: consider progression criteria from the earliest opportunity; map progression criteria to feasibility objectives; consider quantitative and qualitative interpretations of feasibility; provide justification; develop guidelines rather than rules; seek input from relevant stakeholders. ii. Conduct: regularly monitor pilot trial data against progression criteria. iii. Analysis: avoid considering each progression criterion in isolation; engage in discussion with relevant stakeholders; consider context and other factors external to the pilot trial; consider feasibility (can we?) and progression (will we?). iv. Reporting: we propose a reporting checklist in relation to progression criteria and recommend reporting in a table format for clarity. CONCLUSION: These recommendations provide a helpful resource for researchers to consider progression criteria at different stages of external randomised pilot trials. We have produced a simple infographic tool to summarise these recommendations for researchers to refer to. Further research is needed to evaluate whether these proposed recommendations should inform future development, or update, of established guidelines for the design, conduct, analysis and reporting of external randomised pilot trials.