Background: Unanticipated responses by research participants can influence randomised
controlled trials in multiple ways, many of which are poorly understood. This study used
qualitative interviews as part of an embedded process evaluation to explore the impact
participants may have on the study, but also unintended impacts the study ...
Background: Unanticipated responses by research participants can influence randomised
controlled trials in multiple ways, many of which are poorly understood. This study used
qualitative interviews as part of an embedded process evaluation to explore the impact
participants may have on the study, but also unintended impacts the study may have on
them.
Aim: To explore participants’ experiences and impact of trial involvement in a pilot
randomised controlled trial (RCT) in order to inform the designing and delivery of a
definitive RCT.
Methods: In-depth interviews with 20 participants (10 intervention and 10 control group)
enrolled in a stroke rehabilitation pilot trial. Analysis of transcripts used a modified
framework approach.
Results: Participation in the study was motivated partly by a desperation to get further
rehabilitation after discharge. Responses to allocation to the control group included an
increased commitment to self-treatment, and negative psychological consequences were
also described. Accounts of participants in both control and intervention groups challenge
the presumption that they were neutral, or in equipoise, regarding group allocation prior to
consenting to randomisation.
Conclusions: Considering and exploring participant and participation effects, particularly in
the control group, highlights numerous issues regarding interpretation of trial studies, as
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well as the ethics of randomised controlled trials more generally. While suggestions for a
definitive trial design are given, further research is required to investigate the significant
implications these findings may have for trial design, monitoring and funding.
