Non-retention of participants seriously affects the credibility of clinical trial results and significantly affects a trial’s potential to influence clinical practice. Non-retention could be defined as instances where participants are prematurely ‘off-study’ such as consent withdrawn or lost to follow-up and thus outcome data cannot be obtained from them.

Many of the causes of non-retention involve people performing, or not performing, an action such as returning a questionnaire, in other words, performing a behaviour.  Behaviour change is difficult, and the importance of a strong theoretical basis for interventions that aim to change behaviour is increasingly recognised. The majority of existing interventions targeting retention fail to describe any theoretical (i.e., generalizable) basis for the observed outcome.  Moreover, most of these interventions lack involvement of participants in their conception and/or design, raising questions about their relevance and acceptability.

STEER aims to develop and pilot theoretically-informed, participant-centred, evidence-based behaviour change interventions to improve retention in trials. To achieve this, our project comprises of four interrelated phases and the research objectives are:

a) Identify the problem (identify stakeholders’ views and experiences of non-retention to determine ‘who needs to do what differently?’);

b) Assess the problem (use a theoretical framework to identify which barriers and enablers to retention in trials need to be targeted);

c) Form possible solutions (which behaviour change techniques could overcome the modifiable barriers and enhance the enablers of trial retention and how best could these techniques be presented); and

d) Evaluate feasibility and acceptability of the selected interventions (explore the feasibility and acceptability of potential interventions from the perspective of stakeholders and how retention interventions can be implemented in new and ongoing trials).

The STEER project is funded by the Chief Scientist Office of the Scottish Government’s Health and Social Care Department and led by Katie Gillies at the University of Aberdeen.

Please read our protocol for further details:

Our Shaun Treweek and Katie Gillies have written a blog on the Trial retention: it’s time for Cinderella to go to the ball, which is available at





Newlands R, Duncan E, Presseau J, Treweek S, Lawrie L, Bower P, Elliott J, Francis J, MacLennan G, Ogden M, Wells M, Witham MD, Young B & Gillies K.

Why trials lose participants: A multitrial investigation of participants’ perspectives using the theoretical domains framework. Journal of Clinical Epidemiology, Volume 137, 2021,Pages 1-13

Newlands R, Duncan E, Treweek S, Elliott J, Presseau J, Bower P, MacLennan G, Ogden M,, Wells M, Witham MD, Young B & Gillies K. The Development of Theory-Informed Participant-Centred Interventions to Maximise Participant Retention in Randomised Controlled Trials BMC 2021 DOI:10.21203/