title: Defining Feasibility and Pilot Studies in Preparation for Randomised Controlled Trials: Development of a Conceptual Framework.
abstract: We describe a framework for defining pilot and feasibility studies focusing on studies conducted in preparation for a randomised controlled trial. To develop the framework, we undertook a Delphi survey; ran an open meeting at a trial methodology conference; conducted a review of definitions outside the health research context; consulted experts at an international consensus meeting; and reviewed 27 empirical pilot or feasibility studies. We initially adopted mutually exclusive definitions of pilot and feasibility studies. However, some Delphi survey respondents and the majority of open meeting attendees disagreed with the idea of mutually exclusive definitions. Their viewpoint was supported by definitions outside the health research context, the use of the terms 'pilot' and 'feasibility' in the literature, and participants at the international consensus meeting. In our framework, pilot studies are a subset of feasibility studies, rather than the two being mutually exclusive. A feasibility study asks whether something can be done, should we proceed with it, and if so, how. A pilot study asks the same questions but also has a specific design feature: in a pilot study a future study, or part of a future study, is conducted on a smaller scale. We suggest that to facilitate their identification, these studies should be clearly identified using the terms 'feasibility' or 'pilot' as appropriate. This should include feasibility studies that are largely qualitative; we found these difficult to identify in electronic searches because researchers rarely used the term 'feasibility' in the title or abstract of such studies. Investigators should also report appropriate objectives and methods related to feasibility; and give clear confirmation that their study is in preparation for a future randomised controlled trial designed to assess the effect of an intervention.
authors.affiliation: Centre for Primary Care and Public Health, Queen Mary University of London, London, United Kingdom.
authors.forename: Sandra M
authors.initials: SM
authors.lastname: Eldridge
authors.affiliation: Department of Mathematics and Statistics, Lancaster University, Lancaster, Lancashire, United Kingdom.
authors.forename: Gillian A
authors.initials: GA
authors.lastname: Lancaster
authors.affiliation: School of Health and Related Research, University of Sheffield, Sheffield, South Yorkshire, United Kingdom.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Campbell
authors.affiliation: Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Lehana
authors.initials: L
authors.lastname: Thabane
authors.affiliation: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, Oxfordshire, United Kingdom.
authors.forename: Sally
authors.initials: S
authors.lastname: Hopewell
authors.affiliation: Centre for Primary Care and Public Health, Queen Mary University of London, London, United Kingdom.
authors.forename: Claire L
authors.initials: CL
authors.lastname: Coleman
authors.affiliation: Centre of Academic Primary Care, University of Aberdeen, Aberdeen, Scotland, United Kingdom.
authors.forename: Christine M
authors.initials: CM
authors.lastname: Bond
mesh_terms: D003697:Delphi Technique; D005240:Feasibility Studies; D010865:Pilot Projects; D016032:Randomized Controlled Trials as Topic; D054928:Validation Studies as Topic