Retention in Randomised Trails

About this PSP

This project, established in late 2017, aimed to collect information from people across the UK and Ireland who were, or had been, involved directly, in designing, running, analysing, or taking part and/or staying involved in randomised trials (see below for an explanation of what trials are). The aim was to help improve what we know about the best ways to encourage people to stay involved in clinical trials.

Most trials collect data from participants as part of their continued involvement in the trial and will help to answer whether one treatment is better than another. This is known as “follow-up”. Some trials collect data long after the treatments being tested have been given.

Retention refers to the number of people staying involved or “followed up” in trials and whether they complete or provide all the measurements the trial team needs. For example, the trial may ask participants to return for a study visit or return a questionnaire. This is important because if people join a trial but cannot be followed up, the trial results may be inaccurate and misleading which wastes vital research time and money.

The Top 10 priorities were published in March 2019.

Katie Gillies talks about PRioRiTy II


Project website
Articles and publications

Top 10 priorities

  1. What motivates a participant’s decision to complete a clinical trial?
  2. How can trials make better use of routine clinical care and/or existing data collection to improve retention?
  3. How can trials be designed to minimise burden on staff and participants and how does this affect retention?
  4. What are the best ways to encourage trial participants to complete the tasks (e.g. attend follow-up visits, complete questionnaires) required by the trial?
  5. How does involvement of patients/the public in planning and running trials improve retention?
  6. How could technology be best used in trial follow-up processes?
  7. What are the most effective ways of collecting information from participants during a trial to improve retention?
  8. How does a participant’s ongoing experience of the trial affect retention?
  9. What information should trial teams communicate to potential trial participants to improve trial retention?
  10. How should people who run trials plan for retention during their funding application and creation of the trial (protocol development)?

The following questions were also discussed and put in order of priority at the workshop:

  1. What aspects of trial recruitment processes could be changed to improve retention?
  2. What aspects of trial retention do participants perceive as burdensome and how can these be addressed?
  3. What influence does the relationship between trial staff and participants have on retention?
  4. How does a sense of belonging or being part of something amongst trial participants affect retention?
  5. What are the best approaches for designing and communicating information about trial retention for trial participants?
  6. To what extent (if any) do studies that explore retention procedures before the main trial (i.e. feasibility study) lead to improvements in retention in the main trial?
  7. What is the impact of timing, frequency and duration of follow up (e.g. questionnaires, clinic appointments) on retention?
  8. What strategies (e.g. sending Christmas cards or saying ‘thank you’) make participants feel valued and how do they affect retention?
  9. What are the best strategies for using participant incentives (e.g. monetary or non-monetary) and how should they be implemented (e.g. when should they be provided) when collecting information from participants in clinical trials?
  10. How does continuity (e.g. seeing/speaking to the same staff) and consistency (e.g. of trial information) affect retention?
  11. What behaviours of trial staff (e.g. being friendly) result in improved retention?