The importance of study feasibility

question-answerWith the finances involved and continuing risk of failure, the importance of careful feasibility assessment and judgment is absolute.

To what extent weak – or no – feasibility assessment contributes to clinical trial failures is a challenging question.

Feasibility study

The usual way to assess feasibility is first to carry out a feasibility study. This is an investigation done to test if the full trial can be performed. It asks essential questions about:

  • potential barriers to recruitment of participants
  • which sites would meet the project’s budget and timeline while reliably producing good quality data
  • parameters required for the substantive trial


According to Forbes (2012) it takes an average of $4 billion (2.94 billion euros, £2.35 billion) to develop a drug, a significant part of which is spent on clinical development. Before investing this heavily in clinical research, it needs to be demonstrated that:

  • there are enough eligible participants
  • participants at potential investigation sites are willing to be randomized
  • participants are enthusiastic about clinical trials, with good rates of follow-up, questionnaire response, treatment adherence / compliance.

Study parameters

As well as gauging the behavior of participants, the feasibility study should assess the readiness of clinicians to recruit their patients to enroll and essential practical details for the trial. These may include:

  • measurable characteristics of the proposed outcome measure
  • designing an appropriate outcome measure
  • standard deviation of the outcome measure (this may be needed to decide the required sample size)
  • accessibility of data (potential of a database)
  • time taken to gather and analyse the data.

Pilot trial

Another assessment often performed before commitment to the full trial is the pilot study. This is a scaled-down version of the full trial that is run to assess whether the study processes, such as randomization and follow-up, will run smoothly.

Assessing the feasibility of a clinical trial accurately and comprehensively before deciding to conduct a clinical trial is clearly essential.

Funding: route of progression

The EME (Efficacy and Mechanism Evaluation), PHR (Public Health Research), HTA (Health Technology Assessment) and RfPB (Research for Patient Benefit) programmes agreed that bids for funding, and commissioning briefs, should include the series of criteria required to progress to the full trial.


An important decision before initiating research is who will be responsible for the feasibility question. Do you want to use a clinical research organization or take care of the essential specifics in house?

Site selection

Deciding on which investigational sites to use is also imperative and will be the dedicated subject of one of our future posts.


Forbes 2012. The truly staggering cost of inventing new drugs.

UCLAN Univesrity of Central Lancashire.

Lancaster GA, Dodd S, Williamson PR. Design and analysis of pilot studies: recommendations for good practice. J Eval Clin Pract 2004, 10:307-12.

Arain M, Campbell MJ, Cooper CL, Lancaster GA. What is a pilot or feasibility study? A review of current practice and editorial policy. BMC Medical Research Methodology 2010, 10:67.

Julious SA. Sample size of 12 per group rule of thumb for a pilot study. Pharmaceutical Statistics 2005, 4:287–291.

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