In the clinical analysis, the authors did not comment upon the evident difference in the case-mix of groups and possible biases arising from this: in the intervention, from the 57 wounds included in the analysis, 30 were stage II ulcers and 27 were skin tears; on the other hand, the comparator had 5 stage II ulcers and 14 skin tears, for a total of 19 wounds. This may have adversely affected the internal validity of the study, although the external validity probably benefits from the simple study design adopted. The authors do not appear to regard reduction in time with an unhealed wound as a clinical benefit, and only use these differences as contributing to costs, even though consideration of such benefits would reinforce DSO as the dominant strategy.