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.

Use of Mental Health Apps by Breast Cancer Patients and Their Caregivers in the United States: Protocol for a Pilot Pre-Post Study (Preprint)

“…Consistent with prior definitions and reasons for conducting a pilot study (11,12), the goals of the present study are to: a) assess the feasibility of various components (e.g., recruitment rates, retention rates, refusal rates) that need to take place in a larger study; b) understand and identify potential human and data optimization issues (e.g., issues of managing the study in a busy clinic, identifying challenges to recruitment from doctors and nurses, whether data show too much or too little variability); and c) examine whether participants respond to the intervention and to obtain estimates of the treatment effects and the variances of treatment effects. Importantly, a pilot study is not only concerned with whether something can be done and how to proceed, but includes implementing something in a way intended in part of a future study [11]. This singlegroup, 7-week pre and post-test pilot study will provide IntelliCare apps to a sample of breast cancer patients and caregivers in the U.S. A mixed-methods approach utilizing selfreport measures and qualitative interviews will be used to evaluate user satisfaction and potential for adoption in a larger and more diverse cancer population.…”

Pilot Testing for Feasibility in a Study of Student Retention and Attrition in Online Undergraduate Programs

“…In general, a pilot precedes and is closely related to a larger study (Prescott & Soeken, 1989;Lancaster, Dodd, & Williamson, 2004;Eldridge et al, 2016). A pilot is often viewed synonymously with a "feasibility study intended to guide the planning of a large scale investigation" (Thabane et al, 2010, p. 1).…”

“…The word pilot has several different meanings in the research literature; however, as Eldridge et al (2016) point out, definitions of pilot studies usually focus on an experiment, project, or development undertaken in advance of a future wider experiment, project, or development. In other words, a pilot study facilitates decision-making, and therefore serves as "a small-scale experiment or set of observations undertaken to decide how and whether to launch a full-scale project" (Collins English Dictionary, 2014, para 1).…”

“…An informal term often used for feasibility is doability; Eldridge et al (2016) observed that outside of the health context, definitions of feasibility and feasibility studies focus on the likelihood of being able to do something easily or conveniently, and on the "assessment of the practicality of a proposed plan or method" (para. 16).…”

Response to: Gschwantler-Kaulich et al (2016) Mesh versus acellular dermal matrix in immediate implant-based breast reconstruction – A prospective randomized trial doi:10.1016/j.ejso.2016.02.007

“…They may aim to determine, for example, whether it is possible to recruit and randomise patients or explore the best primary endpoint for the main trial. They may also test whether the components of the main study can work together 4 . Published reports should be largely descriptive and provide important methodological information such as the standard deviation of the primary end-point to inform a sample-size calculation.…”