Table 1 Suggested reporting items and rationale

Methods

 Pre-specified progression criteria

To ensure the pilot trial meets its (feasibility) objectives, specific measures or assessments should be defined to address each separate objective ^a. A range of methods can be used, and are often based on quantitative descriptive statistics but might also include qualitative narrative descriptions ^b. It is these feasibility objectives and measures that progression criteria should be based on. Estimates of rates in pilot trials may be subject to considerable uncertainty, so investigators should be cautious about setting definitive thresholds that could be missed simply due to chance variation. Instead it is becoming increasingly common to use a traffic light system for criteria used to judge feasibility, whereby measures (e.g. recruitment rates) below a lower (red) threshold indicate major problems that require urgent attention (and perhaps cannot be remedied), amber indicating minor problems that require attention, and green indicating areas of no concern ^c.

✓

✓

 Rationale for progression criteria, including any data or clinical assumptions supporting any targets provided

It should be stated how progression criteria were derived to ensure transparent feasibility assessment. Rationale need not be statistical as pilot trials are usually underpowered for hypothesis testing, but some rationale for criteria should be given (e.g. based on feasibility objectives; clinical or contextual assumptions; pragmatically derived; based on previous feasibility or observational work; developed using consensus methods).

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*

 Brief description of the involvement (role) of different stakeholders in developing, or agreeing, progression criteria

A multidisciplinary team of stakeholders may be involved in developing, or agreeing, progression criteria to avoid bias. Stakeholders who might contribute to progression criteria development include: Clinical Trials Unit; Research Design Service; clinical professionals who will be implementing the pilot trial; PPI representatives; research funders; an independent Trial Steering Committee.

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 Proposed method of multi-criteria assessment

Where pilot trials have multiple progression criteria, researchers should indicate a method of multi-criteria assessment. Researchers might take a holistic approach and consider whether targets were met and whether solutions to poorly performing criteria have been identified to come to an overall conclusion of feasibility. This may involve weighting of specific criteria that are regarded as more fundamental than others. Alternatively, researchers might opt to take a more structured approach to multi-criteria assessment and determine overall progression based on the worst-performing criterion (e.g. if one criterion is not met then the trial is not feasible).

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*

Results

 Any changes to progression criteria after the pilot trial commenced, with reasons

An assessment or measure might change during a pilot trial because the change enables investigators to glean more information about the operation of the intervention or for reasons of acceptability or practicability ^d. These changes might directly or indirectly impact on the applicability of the pre-specified progression criteria. Because of the usefulness of such information to the overall assessment of trial feasibility, all changes to progression criteria should be reported.

✓

 For each progression criterion, findings in terms of whether criteria indicate feasibility and if applicable, whether numerical targets were met

Findings for each progression criteria should be provided to demonstrate which aspects of the pilot trial were considered feasible. Where a RAG system was used researchers should indicate whether each progression criterion was above the upper threshold (green), below the lower threshold (red), or between the two (amber). For any progression criteria that are not based on numerical targets, a clear statement to reflect whether the findings indicate feasibility is sufficient.

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 For each progression criterion, implications for the future definitive trial, including any proposed amendments

It is important to understand how the pilot trial findings have informed the definitive RCT ^e. For each progression criterion researchers should state any implications that their findings have for the definitive trial design. Any proposed changes to trial design should be based on evidence, or experience, generated from the pilot trial.

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 Overall statement of trial feasibility (based on pilot trial findings and any other contextual considerations)

Researchers should provide an overall statement of feasibility based on pilot trial findings and any other contextual considerations, or external evidence, generated whilst conducting the pilot trial. This is important because sometimes progression criteria do not adequately reflect trial feasibility. For example, a pilot trial might be feasible (based on assessment of progression criteria) but not progress for other reasons such as unanticipated challenges or factors external to the pilot trial.

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