“Why don’t they just tell me straight, why allocate it?” The struggle to make sense of participating in a randomised controlled trial

Randomised controlled trials are the acknowledged ‘gold standard’ method of evaluating the effectiveness of treatments, but little is known about how and why patients decide to participate in trials nor how much they understand about trial design. In this study, in-depth, semi-structured interviews were carried out with 33 middle aged and older men with lower urinary tract symptoms related to benign prostatic disease, 22 of whom had consented to participate and 11 refused to take part in a randomised trial. The trial was evaluating the effectiveness of a new technology (laser therapy) compared with standard surgery (transurethral resection of the prostate) and conservative management (monitoring without active intervention) (the CLasP study). Purposive sampling was used to include participants from different centres, each treatment arm, and at different stages in participation, as well as those indicated to have refused participation. Interviews explored their recall and understanding of trial information, and their reasoning about how they were allocated to a treatment. Data were analysed thematically according to the methods of constant comparison, and by examining each participantʹs narrative of their experiences.