Author's response to ‘Evidence is in the eye of the beholder’ letter to the editor

Author response:

Thank you for drawing attention to some areas of my Letter to the Editor that may not have been so clear and to the large volume of systematic and integrative reviews I have conducted with my team. The said systematic reviews always include a large number of studies; the largest being 153 trials, and some of the outcomes of the reviews have led to the development of national guidelines in the UK (i.e., cough-related systematic and Cochrane reviews). Some comments made in the response to my letter are also taken in isolation; for example, I agree that findings of a review cannot be known beforehand, but I was referring to reviews using a couple of studies, when by reading the tiny volume of original studies, we already know that no conclusions can be drawn from them. Finally, the point I was making around sham placebo trials was not that we should not strive to estimate and assess placebo effects [which I agree is crucial], but rather the way we currently do is outdated and perhaps inappropriate and that we need a consensus of how best to do it, so we do not all use different and questionable placebo techniques in our trials that can be criticized or be insufficient to assess placebo effects. I also agree that reviews are about summary judgments, but these judgments should be based on careful appreciation of the specific characteristics of the interventions included, which should be similar enough to allow the “summary judgment” to take place.