What are pilot studies, feasibility studies, and intervention research planning grants?

What is a pilot study?

“A Pilot Study is a version of the main study that is run in miniature to test whether the components of the main study can all work together. It is focused on the processes of the main study, for example to ensure recruitment, randomisation, treatment, and follow-up assessments all run smoothly. It will therefore resemble the main study in many respects. In some cases this will be the first phase of the substantive study and data from the pilot phase may contribute to the final analysis; this can be referred to as an internal pilot. Alternatively at the end of the pilot study the data may be analysed and set aside, a so-called external pilot.” (p. 5)

Pilot studies are characterized by 

  • “rigorous methodological components like sample size estimation, randomization and control group selection” (p. 5)
  • an explicit purpose (e.g., “to test a new procedure in preparation for a clinical trial”) and “the criteria which lead to further studies being abandoned. “ (p. 6)
  • reporting of results are “interpreted with caution” (p. 6) or as “inconclusive, with the intention of conducting a further, larger study” (p. 5)
  • results that “provide information to enable a sample size calculation in a subsequent main study.” (p. 6)

What is a feasibility study?

“Feasibility Studies are pieces of research done before a main study. They are used to estimate important parameters that are needed to design the main study. For instance:

  • standard deviation of the outcome measure, which is needed in some cases to estimate sample size,
  • willingness of participants to be randomised,
  • willingness of clinicians to recruit participants,
  • number of eligible patients,
  • characteristics of the proposed outcome measure and in some cases feasibility studies might involve designing a suitable outcome measure,
  • follow-up rates, response rates to questionnaires, adherence/compliance rates, ICCs in cluster trials, etc

Feasibility studies for randomised controlled trials may not themselves be randomised.  Crucially, feasibility studies do not evaluate the outcome of interest; that is left to the main study…..If a feasibility study is a small randomised controlled trial, it need not have a primary outcome and the usual sort of power calculation is not normally undertaken.  Instead the sample size should be adequate to estimate the critical parameters (e.g. recruitment rate) to the necessary degree of precision. (p. 5)

In general, feasibility studies are “conducted with more flexible methodology compared to those labeled 'pilot'.  For example the term 'feasibility' has been used for large scale studies such as a screening programme applied at a population level to determine the initial feasibility of the programme.” (p. 5) 

Arain, M., Campbell, M. J., Cooper, C. L., & Lancaster, G. A. (2010). What is a pilot or feasibility study? A review of current practice and editorial policy. BMC medical research methodology, 10(1), http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2912920/

What is an intervention research planning grant?

An intervention research planning grant allows a new community (typically multi-disciplinary) of experienced investigators to form and share knowledge and ideas around a shared problem prior to attempting to undertake collaborative intervention research.  The planning grant period allows the PI to determine who is committed to working together in a true collaborative spirit.   The “product” of the planning grant should be a detailed plan for going forward with clearly identified goals for intervention research, a work agenda with defined roles for participants, and a plan for obtaining the needed resources to allow the program to go forward.

What are the key elements for success in a planning grant?

  • A driver – the one person who has the passion and vision and takes a leadership role
  • A team committed to working together with a deep appreciation for why traditional approaches will not solve the problem.
  • Duration – long enough for true planning and collaboration – but short enough to drive a product.
  • A structure that allows for both a focused working group and casting a wide net.
  • An opportunity to involve individuals across the career span – but especially junior people who will then internalize a new model for successful research.
  • A problem that cannot be solved without a novel approach calling on combined expertise
  • A commitment to developing a “common currency” or a shared language – this means developing a respect for other “kinds” of knowledge and for recognizing why a particular, dogmatic approach will not succeed.    This takes time and some discomfort.
  • An atmosphere of trust – individuals must be comfortable pushing one another.
  • A project that has both practical outcomes while contributing the further development of theory.

A planning grant should include goals to:

  • Yield a program of intervention research with real growth potential 
  • Yield operational success – so a component of the application should include a plan for how the program of intervention research identified during the planning process would be supported by identifying pertinent RFAs. 
  • Demonstrate why occupational therapy is central to the intervention research program and its likelihood of success. 
  • Provide a true training component to strengthen capacity for intervention research.

James S. McDonnell Foundation, personal communication




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