Developing theory based behaviour change interventions to minimise drop-out in randomised controlled trials


To develop and pilot theoretically-informed, participant-centred, evidence-based behaviour change interventions to improve retention in trials.


Randomised controlled trials are the cornerstone of evidence-based healthcare as they provide unbiased estimates of the benefits and harms of treatment if conducted rigorously. It is common for many trial participants (sometimes more than 20%) to drop out before the trial finishes. Moreover, 50% of trials have loss to follow up of over 11%. This study will use an established theoretical framework (Theoretical Domains Framework, TDF) to inform the development of targeted retention interventions for use in future trials. Five ‘host’ trials with poor retention (e.g. those with more than 15% missing primary outcome data) from the portfolios of Trials Units will be purposively selected.  Semi-structured interviews with participants who have dropped out, or considered dropping out, of these host trials will be conducted. The barriers and enablers to retention that are reported by trial stakeholders will be linked to retention-relevant domains of the TDF and used to identify specific behaviour change techniques.  Co-production workshops will then be held to develop retention interventions. 


If successful, these interventions will directly lead to an improved evidence base on which clinical care treatment choices are made.

Principal Investigator: University of Aberdeen

NMAHP Research Unit Collaborators: Professor Mary Wells

External Collaborators: Bower P - Manchester University, Frances J - City University, Treweek S - University of Aberdeen, Witham M - University of Dundee, Young B - Liverpool University

Funder: Chief Scientist Office