Feasibility and Investigator Selection


Non-commercial trials which fail to meet their targets often result in a request for further funding, or may fail to achieve a statistically significant result. It is important that a proper feasibility assessment is undertaken for any proposed trial.

For larger trials, the sponsor should consider, during the funding process, whether a feasibility or pilot study should be undertaken.

In all cases the sponsor should ensure that any barriers to recruitment have been identified and resolved including:

  • Are protocol requirements aligned with current clinical/medical practice?
  • Are inclusion/exclusion criteria too restrictive?
  • Is the proposed patient recruitment rate realistic?

Patient and Public Involvement (PPI):

Inviting patients to comment on trial design can make studies more feasible. A studylink opens in a new page from King’s College London, published in the British Journal of Psychiatry showed that trials with higher levels of PPI were 4.12 times more likely to recruit to target. PPI can help shape a number of factors that can improve trial feasibility and recruitment by addressing questions such as:

  • Will the proposed recruitment strategy work? 
  • How could it be made easier for a patient to participate?  
  • How likely are participants going to accept the study schedule/requirements?

The Association of Medical Research Charities and the NIHR Medicines for Children Research Network have produced Points to consider when assessing the feasibility of research which provides further guidance.

Other factors will affect a researcher's ability to deliver a trial effectively. For multi-site trials, the careful selection and evaluation of investigator sites is critical for the successful completion of a trial within budget, timelines and to ensure the generation of high quality data. Factors that should influence investigator site selection include:

  • Interest in the research question
  • Experience and qualifications of the investigator
  • Sufficient staff to conduct the study and their experience and qualifications
  • Availability of suitable patient population:
    • Anticipated rate of patient recruitment (determined through feasibility assessments)
    • Conflicting studies (competing for the patient population and potentially introducing recruitment bias)
  • Adequate time to conduct and oversee the trial
  • Adequate facilities:
    • Availability of any specialised diagnostic or therapeutic equipment required by the protocol
    • Adequate space and storage conditions (including archive)
    • Available resources in NHS support departments
  • Track record with similar trials previously
  • Geographic location
  • Contractual and budgetary negotiations and arrangements.

When undertaking site selection, the preparation of ‘reserve’ investigator sites (so that the trial may be extended to these sites if recruitment issues arise) should be considered as part of proactive trial planning.

Further reading: