Trial recruitment: six tips no one tells you

You selected a site with access to plenty of eligible patients, an experienced investigator, a dedicated research team and a strong recruitment record. The feasibility assessment looked convincing. Everyone was optimistic.

Recruitment opened. The first month passed without a recruit. That can happen - trial recruitment often starts slowly.

But by month three, the site was already falling behind. By month six, it had recruited five patients against a target of 20.

You thought you had selected the best site for the job. What happened? Why is the site not recruiting? What can be changed before more time is lost?

Site selection matters, but it cannot guarantee delivery. Conventional feasibility assessments can be burdensome and their effectiveness is uncertain.[1] The local picture can also change. Staff leave. Clinics are reorganised. Other trials begin recruiting from the same patients. In an analysis of 787 phase II and III oncology trials, greater competition from other trials was associated with low accrual.[2]

A feasibility assessment is a forecast. Recruitment tells you whether its assumptions were right.

Members of the Evidax team have collectively spent more than 20 years running and recruiting to hundreds of trials across biotech, academia, healthcare and pharma. These are six practical things we have learned to do after a site has been selected.

1. Plan recruitment with the patients and staff who will actually do it

Do not plan the recruitment pathway only with the principal investigator or treating clinicians.

Speak to the nurses, allied health professionals, clinic coordinators and/or R&D staff involved in the patient’s care or the clinic’s operation. Involve patients too.

These are often the people who know how the clinic really works. They know who can access the patient list, when records can be screened, which appointment is suitable for introducing research and who patients already trust.

Speak to patients about how, when and by whom they should be approached. Recruitment to a trial often happens at a vulnerable time, such as diagnosis or disease progression, so getting the approach right matters more than you think.

Published recruitment guidance recommends involving potential recruiters, patient representatives and other relevant professionals before recruitment begins.[3] Patient-centred research also shows why this matters. Trust, timing, communication and the burden of participation all affect how an invitation is received.[4,5]

2. Do the site initiation visit in person, then stay in touch

Do the site initiation visit in person. Read that again.

Meet the people who will screen, approach and consent patients. See where the work will happen. Walk through the recruitment pathway with them and ask what will be difficult on a busy clinic day.

A signed training log tells you that training happened. It does not tell you whether recruitment will work on Monday morning.

The visit should begin the relationship, not complete a checklist. Put a regular rolling call in the diary afterwards. Cancel it when neither side has an agenda.

This is not about filling calendars. Recruiting staff have limited time and it should not be wasted. The point is to give them a predictable opportunity to ask questions, raise problems and feel heard.

Regular contact also makes it easier to tailor support. A structured recruitment intervention developed across 13 randomised trials used interviews, recruitment data and feedback to understand how recruitment was actually working, then address the specific problems found.[6]

The call can be simple:

What has happened since we last spoke?
What is getting in the way?
What do you need from us?

If there is nothing to discuss, give the time back.

3. Give every task an owner and name who is accountable at each site

Every recruitment task needs a named owner.

Who screens the medical records? Who confirms eligibility? Who approaches the patient? Who introduces the study? Who answers questions? Who takes consent? Who records the recruitment outcome?

Then name one person who is accountable for recruitment operations across the site. This may be the principal investigator. Often it is a research nurse, associate principal investigator, sub-investigator, trial coordinator or another team member with more capacity to monitor recruitment day to day.

That person should know the target, review progress, bring the right people together and make sure agreed actions happen. The principal investigator still retains formal oversight of delegated trial activities under Good Clinical Practice.[7]

The distinction between two logs matters here.

The delegation log records which staff are authorised to perform trial activities. The screening log records what happened to potential participants.

Name who records each recruitment outcome. Make sure that activity is assigned appropriately on the delegation log. Review the outcomes themselves in the screening or recruitment log.

Name backups too. People take annual leave, become unwell and change roles. If one person’s absence stops screening or consent, the recruitment pathway is too fragile.

Every task needs an owner. Every site needs someone accountable. This gives you someone to speak to directly if part of the recruitment pathway becomes a bottleneck. But that only works if you have built a relationship with them. See Tip 2.

4. Compare expected eligible patients with the number actually approached

Before recruitment starts, ask the clinical team how many patients they expect to be eligible each month. Record the estimate and the assumptions behind it.

Then compare it with what happens.

The SEAR framework separates recruitment into four stages: screened, eligible, approached and randomised.[8] The same logic can be adapted to the stages in your trial. The important point is not to look only at the final number recruited.

Suppose the clinical team expects 20 eligible patients each month, but the screening log shows that only five are being approached.

That discrepancy gives you something useful to discuss.

Were fewer patients eligible than expected? Were records not being screened? Was the usual screener away? Were eligible patients attending a clinic where nobody had time to approach them? Had another trial begun recruiting from the same population? Were patients declining, and if so, why?

Review the screening or recruitment log during the regular site calls. Look at the numbers screened, eligible, approached and enrolled, alongside appropriately collected reasons for ineligibility or declining participation.

Remain flexible. If the log shows that the pathway is failing, change the pathway. That might mean screening on a different day, involving another member of the clinical team, changing when the study is introduced or simplifying an unnecessary step.

Any change must remain within the approved protocol and recruitment procedures, or follow the required amendment process.

“Recruitment is slow” is not a diagnosis. Find where the numbers begin to diverge.

5. Make it easy for the recruitment team

Recruiting staff are busy. Do not make them search a long protocol to check one eligibility criterion or invent a balanced explanation of the study while a patient is waiting.

Give them tools they can use in the clinic.

PURE-EX is a multisite study of physical activity support after breast cancer treatment.[9] In that trial, we gave recruiting teams a one-page printable eligibility checklist. We also literally gave them an opening script when approaching patients.

The checklist could be kept where screening happened. The script meant staff did not have to think of the first sentence each time they introduced the study.

This was not a sales script. It was a short, approved prompt for starting a consistent and balanced conversation. Even better, the script was vetted by patients and site staff involved in recruitment. It, of course, did not replace the participant information or informed consent process.

Ask what would remove effort from the recruitment team:

Can the eligibility criteria fit on one page?
Can the opening explanation be written for them?
Is the screening log simple and easy to use?
Is there one clear contact when they have a question?
Can repeated information be entered once rather than copied between systems?

6. Give the recruitment team coffee vouchers

I am not joking. This is important.

Recruiting staff often fit research around pressured clinical work. They screen records between other tasks, answer patient questions and use time that could have been spent on something else.

A modest coffee voucher will not repair a broken recruitment pathway. But it does tell people that their work has been noticed.

Do the governance work before sending one. Ask the site’s R&D, research governance or conflicts team what is permitted. Keep the value modest and apply the approach consistently. It is a thank you, not a payment for each patient recruited.

Policies differ between countries and organisations. NHS England guidance says that cash and vouchers should be declined, while proportionate refreshments may be acceptable as hospitality where there is a legitimate business reason.[10]

Where low-value vouchers are explicitly permitted, use them.

Just find a legitimate way to buy the recruitment team a coffee to say thank you. It is worth it.

Take home

A promising site can still recruit poorly. Treat the feasibility estimate as a forecast and check it against delivery.
Plan recruitment with patients and the staff who will actually screen, approach and consent them.
Do the site initiation visit in person. Keep a rolling call in the diary and cancel it when there is no agenda.
Give every recruitment task an owner and a backup. Name one person who is accountable for recruitment operations at each site.
Compare expected eligible patients with the numbers actually screened, approached and enrolled. Use the discrepancy to find the problem.
Make recruitment easy with simple tools such as a printable eligibility checklist and an approved opening script.
Give the recruitment team coffee vouchers through an approved route. If vouchers are prohibited, find a way.

References

Kurbegov D, Hurley P, Waterhouse DM, et al. Recommendations to streamline and standardize clinical trial site feasibility assessments: an ASCO Research Statement. JCO Oncology Practice. 2021;17(1):41-51. https://doi.org/10.1200/OP.20.00821
Bennette CS, Ramsey SD, McDermott CL, Carlson JJ, Basu A, Veenstra DL. Predicting low accrual in the National Cancer Institute’s Cooperative Group clinical trials. Journal of the National Cancer Institute. 2016;108(2):djv324. https://doi.org/10.1093/jnci/djv324
Mills N, Clark M, Young B, Murray G, Williamson P, Donovan J, Bhopal R, Blazeby J, on behalf of the HTMR Recruitment Working Group. HTMR Network Top-tips for Trial Recruitment. Version 0.1. July 2013.
Anastasi JK, Capili B, Norton M, McMahon DJ, Marder K. Recruitment and retention of clinical trial participants: understanding motivations of patients with chronic pain and other populations. Frontiers in Pain Research. 2024;4:1330937. https://doi.org/10.3389/fpain.2023.1330937
Chen M, Reh N, Dwarampudi SR, et al. Strategies for optimizing clinical trial recruitment: perspectives among patients with breast cancer. Cancer Causes & Control. 2026;37:52. https://doi.org/10.1007/s10552-026-02140-5
Donovan JL, Rooshenas L, Jepson M, et al. Optimising recruitment and informed consent in randomised controlled trials: the development and implementation of the QuinteT Recruitment Intervention (QRI). Trials. 2016;17:283. https://doi.org/10.1186/s13063-016-1391-4
International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use. ICH Harmonised Guideline: Guideline for Good Clinical Practice E6(R3). Adopted 6 January 2025. https://database.ich.org/sites/default/files/ICH_E6%28R3%29_Step4_FinalGuideline_2025_0106.pdf
Wilson C, Rooshenas L, Paramasivan S, et al. Development of a framework to improve the process of recruitment to randomised controlled trials (RCTs): the SEAR (Screened, Eligible, Approached, Randomised) framework. Trials. 2018;19:50. https://doi.org/10.1186/s13063-017-2413-6
Orange ST, Brown MC, Hallsworth K, et al. Co-development of a programme to improve physical activity support for women after breast cancer treatment: a pre-protocol for PURE-EX [version 1; peer review: 1 approved with reservations]. NIHR Open Research. 2025;5:3. https://doi.org/10.3310/nihropenres.13773.1
NHS England. Managing conflicts of interest in the NHS. https://www.england.nhs.uk/long-read/managing-conflicts-of-interest-in-the-nhs/