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Monash Bioeth Rev. 2016 Mar;34(1):23-36. doi: 10.1007/s40592-016-0057-z.

What questions can a placebo answer?

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Division of Pharmacoepidemilogy and Pharmacoeconomics, Brigham and Women's Hospital, Harvard Center for Bioethics, Harvard Medical School, Boston, MA, USA.
Rotman Institute of Philosophy, Western University, Stevenson Hall 2150c, London, ON N6A 5B8, Canada.


The concept of clinical equipoise restricts the use of placebo controls in clinical trials when there already exists a proven effective treatment. Several critics of clinical equipoise have put forward alleged counter-examples to this restriction-describing instances of ethical placebo-controlled trials that apparently violate clinical equipoise. In this essay, we respond to these examples and show that clinical equipoise is not as restrictive of placebos as these authors assume. We argue that a subtler appreciation for clinical equipoise-in particular the distinction between de facto and de jure interpretations of the concept-allows the concept to explain when and why a placebo control may be necessary to answer a question of clinical importance.


Clinical equipoise; Placebo controls; Randomized controlled trials; Research ethics

[Indexed for MEDLINE]

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