Proxy consent to clinical research participation: how should it be justified?

In situations where first-hand, contemporaneous consent cannot be obtained from potential research participants-such as from those who lack competence-consent may be sought from a proxy, such as a family member. Such proxy consent must be shown to have a sound moral justification if it is to be an acceptable alternative to first-hand consent. Two standards traditionally proposed for this purpose are those of substituted judgment and best interests. We describe and discuss the limitations of these two approaches, with particular reference to ways in which the context of research differs from that of clinical practice, where proxy consent has been more widely utilized. Other approaches that expand upon or depart from these traditional justifications are then discussed, namely the authentic life, endorsed life, and substituted interests models, as well as one that grounds proxy consent in a putative obligation to participate in research. Whilst these models obviate some of the limitations of the substituted judgment and best interests approaches, they have shortcomings of their own, and do not take full account of all of the relevant values and motivations that obtain in the context of clinical research. We propose an alternative and, in our view, more fruitful approach to justifying proxy consent to research participation-based on W D Ross's moral intuitionism-that does not rest upon a single moral principle but can accommodate a range of both deontological and consequentialist prima facie values.