Should weaker study designs ever be preferred over randomised controlled trials

Randomised controlled trials are typically cited as the 'best' form of study design to be used when comparing the efficacy or effectiveness of different devices such as pressure-redistributing beds and mattresses. This article presents a RCT that compared two forms of alternating pressure air mattress. No statistically significant differences were found between the incidence of sores upon the two mattresses. However the study was under-powered, and so was unlikely to identify differences in efficacy should they have existed. In discussion it is suggested that randomised controlled trials may be less useful to those purchasing mattresses than 'weaker' study designs that capture the experience of the users of such devices.