equipoise

n.

a state of genuine and substantial uncertainty as to which of two or more courses of action will be best for a patient. Equipoise is an important ethical principle in the construction of clinical trials. It is generally held that the random allocation of patients to one or other arm of a trial is ethically acceptable only when there is a genuine uncertainty (equipoise) as to which treatment will benefit them most. Knowingly to assign an individual to inferior or ineffective treatment (such as a placebo) would offend against the principle that his or her best interests are paramount. A distinction is sometimes made between clinical equipoise, which refers to uncertainty across the medical profession as a whole, and theoretical equipoise, which refers to the uncertainty of an individual doctor. If the patient has his or her own preferences among offered treatments, especially if there are trade-offs to be made, it may be paternalistic not to follow these.