Thanks for the link. I note that it reports, "Nevertheless, it is important to mention that according to an influential 2001 meta-analysis comparing placebo-treatment arms with no treatment, placebos make no clinical difference." The citation at that sentence is to an article that lives online in free full text[1] that we can all download and read.

The same team's updated Cochrane review[2] still sums up the evidence by saying, "We found an effect on patient-reported outcomes, especially on pain. Several trials of low risk of bias reported large effects of placebo on pain, but other similar trials reported negligible effect of placebo, indicating the importance of background factors." They add a caution about experimental methods consistent with the article submitted here on HN: "The use of placebos in blinded randomised trials is a precaution directed against many forms of bias, and not only against effects of placebo. Unblinded patients may differ from blinded ones in their way of reporting beneficial and harmful effects of treatment, in their tendency to seek additional treatment outside the study, and in their risk of dropping out of the study. Furthermore, unblinded staff may differ in their use of alternative forms of care and in their assessment of outcomes. Thus, even if there were no true effect of placebo, one would expect to record differences between placebo and no-treatment groups due to bias associated with lack of blinding."

[1] https://math.dartmouth.edu/~doyle/docs/40/PlaceboArticle.pdf

[2] http://summaries.cochrane.org/CD003974/COMMUN_placebo-interv...