Freedman's 'clinical equipoise' and sliding-scale all-dimensions-considered equipoise'

It is often claimed that a clinical investigator may ethically participate (e.g., enroll patients) in a trial only if she is in equipoise (if she has no way to ground a preference for one arm of the study). But this is a serious problem, for as data accumulate, it can be expected that there will be a discernible trend favoring one of the treatments prior to the point where we achieve the trial's objective. In this paper, I critically evaluate Benjamin Freedman's 'clinical equipoise' solution to this dilemma. I argue that Freedman actually puts forth at least two distinct contrasts--one in terms of community vs. individual equipoise, and another concerning clinical vs. theoretical equipoise--and that neither of them resolves the dilemma. I then make a proposal for a more adequate account of how to think about the circumstances under which entering subjects in trials would be justified--a 'sliding-scale equipoise' that arises out of a discussion of patients' values.