Table 1 Approaches to developing and modifying the trial design with particular reference to the recruitment strategy
From: The curious case of an internal pilot in a multicentre randomised trial—time for a rethink?
Approach | Conception | When to use | Key purpose | Main output |
|---|---|---|---|---|
Feasibility study | Separate study | Substantial uncertainty about whether it is possible or how to implement aspects of the trial design and conduct (e.g. delivery of the interventions and recruitment process) | Exploration of the feasibility of a trial | Assessment of the feasibility of a trial |
Pilot trial | Separate study | Limited refinement of the trial design, processes and recruitment strategy anticipated | Refinement of trial design and processes prior to commencement of the main trial | Minor modifications to trial design and confirmation of practicality |
Stop-go assessment | Early in the recruitment period of the main trial | Substantial adjustment of recruitment strategy and study processes is considered likely | One-off within study assessment of recruitment and study processes to allow adjustment of the strategy (including the possibility of early cessation of recruitment) | Single reassessment of the recruitment and data collection strategy |
Routine monitoring | Throughout the recruitment period of the main trial | Minor modifications to study processes and recruitment strategy anticipated | Regular monitoring to allow periodic within study modification | Periodic updating of the recruitment strategy and study processes |