Evidence-appraisal glossary
Clinical equipoise
Clinical equipoise is a state of genuine uncertainty within the expert medical community about which treatment in a trial is better. It is the ethical condition generally required to justify randomly assigning patients to the arms of a study.
Also called: equipoise.
Equipoise means the collective evidence does not favor one arm, so no participant is knowingly assigned to care believed to be inferior, and it can be lost partway through as interim data accumulate. It refers to uncertainty across the community, not the private hunch of any single clinician. When equipoise disappears, continuing to randomize can become unethical, which is one reason trials are monitored as they run.
Read the full Reading the Evidence blog.
This is a plain-language methodology definition for reading research. It is general education, not medical advice.