The problem of bias in behavioural intervention studies: Lessons from the PACE trial, by Carolyn Wilshire in Journal of Health Psychology [Preprint 23 March 2017]
Geraghty’s recent editorial on the PACE trial for chronic fatigue syndrome has stimulated a lively discussion. Here, I consider whether the published claims are justified by the data. I also discuss wider issues concerning trial procedures, researcher allegiance and participant reporting bias.
Cognitive behavioural therapy and graded exercise therapy had modest, time-limited effects on self-report measures, but little effect on more objective measures such as fitness and employment status.
Given that the trial was non-blinded, and the favoured treatments were promoted to participants as ‘highly effective’, these effects may reflect participant response bias. In non-blinded trials, the issue of reporting biases deserves greater attention in future.