This concept inadvertently conflates two distinct concepts, and neither one provides a convincing resolution of the moral dilemma posed by clinical trials.2,3 Most of the essay by Weijer et al focuses on just one of these, which should really be termed “community equipoise” (the situation where not all within the community of “experts” have come to agreement that one treatment is superior to another). Enkin raises one problem with this criterion: that it fails to take seriously the clinical and moral judgment of the individual physician. But a closer look at community equipoise shows in addition that, once we understand that a policy decision (to stop the trial, announce the results, approve the drug, etc) requires a greater amount of evidence than does an individual decision to choose what is best for one's present patient, then community equipoise will typically be disturbed long before we obtain the predetermined level of statistical significance required to support the policy decision.
The concluding suggestions made by Weijer et al, concerning their preferred criterion embodying a pragmatic approach, involve instead a distinct contrast—clinical (as opposed to theoretical) equipoise. Thus these comments will not help make the case for community over individual equipoise. For it is one thing to distinguish two kinds of questions, a theoretical question about whether a drug has a causal effect on the incidence of a certain simple, well-defined outcome, and a practical or clinical question about whether that drug is a better treatment overall for a certain set of patients than is another drug. But it is a different matter to distinguish two modes of assessment of either one of these questions: “What do I think concerning whether there is evidence for the claim?” or, “Is there community agreement concerning this?” For there to be hope of attaining community agreement on these matters, both clinical equipoise and the uncertainty principle will require further scrutiny.