What questions can a placebo answer?

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


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.

Keywords: Clinical equipoise; Placebo controls; Randomized controlled trials; Research ethics.

Publication types

  • Review

MeSH terms

  • Biomedical Research*
  • Control Groups
  • Ethics, Research*
  • Humans
  • Placebo Effect
  • Placebos*
  • Randomized Controlled Trials as Topic


  • Placebos