Equipoise: an appropriate standard for ethical review of nursing research?

When using control-group methodologies, the provision of different forms of treatment, which may vary in efficacy, to similar groups of research subjects must be ethically justified. The conventional justification is the existence of a state of clinical equipoise, defined as a lack of consensus among the expert community on the relative efficacy of the treatments. Control groups are justified when the profession does not know which treatment confers more benefit; otherwise, the provision of treatment known to be less effective than other available treatment is unethical. The concept of equipoise was developed to justify clinical trials of medical interventions. Equipoise has proven a durable standard in studies of interventions that confer benefit regardless of the subject's perception. However, equipoise does not apply when a substantive benefit is conferred by the subject's perception. In psychosocial interventions, a subject's experience of the intervention confers benefit and is used to evaluate benefit. Therefore the subject is in a valid position to prefer one treatment over the other and equipoise does not apply.