The most important study on the placebo effect is Hróbjartsson and Gøtzsche’s Is The Placebo Powerless?, updated three years later by a systematic review and seven years later with a Cochrane review. All three looked at studies comparing a real drug, a placebo drug, and no drug (by the third, over 200 such studies) – and, in general, found little benefit of the placebo drug over no drug at all. There were some possible minor placebo effects in a few isolated conditions – mostly pain – but overall H&G concluded that the placebo effect was clinically insignificant. Despite a few half-hearted tries, no one has been able to produce much evidence they’re wrong. This is kind of surprising, since everyone has been obsessing over placebos and saying they’re super-important for the past fifty years.
Powerless Placebos
[All things that have been discussed here before, but some people wanted it all in a convenient place] The most important study on the placebo effect is Hróbjartsson and Gøtzsche’s Is The Pla…
I've been misunderstanding the placebo effect. The placebo control group is still useful to hell remove bias. sciencebasedmedicine.org
I'm not quite as dismissive as the author. In a sense, what this is saying is that the placebo effect influences our perception, not the physical ailment itself. Things like a broken bone is not affected at all, while pain – largely a psychological construct – is affected a fair bit.