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. 2011;2011:842767.
doi: 10.1093/ecam/neq074. Epub 2011 Apr 14.

Revisiting the Sham: Is It All Smoke and Mirrors?

Free PMC article

Revisiting the Sham: Is It All Smoke and Mirrors?

Brandon Horn et al. Evid Based Complement Alternat Med. .
Free PMC article


The misuse of sham controls in examining the efficacy or effectiveness of Complementary and Alternative Medicine has created numerous problems. The theoretical justification for incorporating a sham is questionable. The sham does not improve our control of bias and leads to relativistic data that, in most instances, has no appropriate interpretation with regards to treatment efficacy. Even the concept of a sham or placebo control in an efficacy trial is inherently paradoxical. Therefore, it is prudent to re-examine how we view sham controls in the context of medical research. Extreme caution should be used in giving weight to any sham-controlled study claiming to establish efficacy or safety.


Figure 1
Figure 1
Possible effects of a sham control.
Figure 2
Figure 2
Placebo effect paradox in an efficacy trial.

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