Abstract
Equipoise, or the criterion of honest professional uncertainty in the clinical community, is currently the most widely accepted standard for adjudicating the ethical dilemmas of medical research involving human patients. Nonetheless, equipoise has recently become a subject of considerable criticism. Among the objections to equipoise, an important one is based on the observation of an objective difficulty for equipoise in providing sound ethical guidance in practical circumstances that arise in clinical research. A chief example of such problem is represented by the case of monitoring accumulating data from a trial. In this article we argue that the perceived inadequacy of equipoise in this context is caused by a widespread misconception of the relation between equipoise and more fundamental ethical principles. We argue that, when interpreted as a mid-level principle, the value of equipoise as the appropriate ethical guidance for clinical research becomes more firmly established.