Feasibility & Investigator Selection

Feasibility & Investigator Selection

Trial Feasibility

Clinical trial sponsors may undertake preliminary studies to assess the practicality and design of a proposed trial before committing to full-scale implementation. For example, during the funding process, the sponsor may consider conducting a feasibility study, particularly for larger or more complex trials. These studies aim to determine whether a full-scale trial is practical and, if so, inform how it should be designed and delivered. 

Pilot studies are a subset of feasibility studies that are smaller versions of the planned trial that test key design features, such as recruitment, randomisation, or data collection methods, to identify potential issues and refine procedures. The National Institute for Health and Care Research (NIHR) provides guidance on feasibility and pilot studies and outlines which of its funding programmes will support them. 

Who can be a Principal Investigator or Chief Investigator?

The amended Clinical Trials Regulations have broadened the range of health care professionals eligible to serve as Chief Investigator and Principal Investigator. The expanded list is available on the Health Research Authority (HRA) Update to Existing Definitions webpage.

Investigator Selection 

The NIHR provides support to optimise the identification of investigator sites. 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.

Once a trial is on the NIHR RDN Portfolio, researchers can access a range of support services. 

Support for Investigator Selection 

• Support with study delivery through the NIHR RDN: Supports non-commercial trial planning from early stages by helping investigators identify extra research sites, including Patient Identification Centres (PICs).
• Find, Recruit, and Follow-Up Service: Helps researchers use data and digital tools to support investigator selection, to enable individuals identified by data analysis to be approached to take part in research and to facilitate patient follow-up by collecting specific events or outcomes.
• Open Data Platform: Provides insights into research activity, recruitment trends, and geographic hotspots using data from the NIHR portfolio, to help identify potential research locations.

Support for Recruitment

• Advice about recruitment strategies, including exploring new recruitment settings (e.g., community, care homes) and the use of digital recruitment methods.
• Access to research registries like Be Part of Research and other digital recruitment tools.
• Identification of additional sites and PICs, if sites are underperforming.
• Monitoring recruitment progress, to troubleshoot barriers to recruitment.

Public Involvement 

Research is starting to show the impact of public involvement on recruitment. For instance, a systematic review in the BMJ found that PPI interventions slightly but significantly increase the chances of participants enrolling, and that involving people who have experienced the condition being studied is linked to better recruitment. Another study found that trials with higher levels of PPI were 4.12 times more likely to reach their recruitment target. PPI can address questions such as:

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

Papers on Recruitment (MRC-NIHR TMRP)

• Guidance on maximising the impact of qualitative research in feasibility studies for RCTs: Helps researchers consider the full range of contributions that qualitative research can make.
• MRC-NIHR TMRP (.PDF): Top-tips for Trial Recruitment of patients to clinical trials (.PDF).
• QuinteT Recruitment Intervention (QRI): A tool to help understand and address recruitment difficulties.
• Understanding and Improving Recruitment to Randomised Controlled Trials: Qualitative Research Approaches: Provides insights into barriers to recruitment.

Further Reading

• NIHR RDN Recruitment Policy Document: Sets out the NIHR RDN policies for the collection of recruitment data relating to studies eligible for NIHR RDN support.
• Clinical Trial Transformation Initiative (CTTI): Recommendations for Trial Recruitment.
• Clinical Trial Site Recruitment Guide: CT:IQ guide to optimising recruitment, including the use of AI.