Coventional medical ethics champions formal advance directives as a means of determining morally appropriate medical care for decisionally incapacitated individuals, and recent legislation such as the Patient Self determination Act implies plies that advance directives are politically acceptable. These observation suggest that advance directives might count as a good method of decision making for decisionally in capacitated patients. But how can we know this To address research priorities relevant to improving decisionmaking for decisionally incapacitated patients, we need at least to begin to answer this question. After all, if we don,t have a set of criteria with which to evaluate formal approaches to decisionmaking, it will be difficult to ask meaningful research questions. In proposing such criteria, I assume that knowing whether an approach is good hinges on knowing whether it is both theoretically plausible and clinically applicable - a good approach will be satisfactory in both domains. Here, then, are five criteria for assessing decisionmaking for decisionally incapacitated patients. 1. The underlying theoretical model must be logical and clear. 2. The approach should be consistent with deeply held societal values such as self-determination, well-being, and justice, at a level where agreement about procedures is possible. 3. Decisions emanating from the approach ought to be empirically reliable and valid.[1] 4. The approach should work in actual clinical settings, that is, the formal model must yield acceptable practical methods for enhancing the care of decisionally incapacitated patients. 5. The processes and outcomes of care should be improved by using an approach consistent with the model. Developing Research Priorities Applying these criteria to the prevailing approach to decisionmaking for decisionally incapacitated patients suggests some areas for potential research. Exemplified in the work of Dan Brock, the prevailing approach is predicated on the assumption that preferences for life-sustaining therapy made in advance of illness validly extend patients, self-determination through situations of decisional incapacity.[2] The theoretical model establishes a clear hierarchy of standards to guide decisionmaking: first priority is given to the patient,s wishes as expressed in an advance directive, second priority goes to substituted judgment and best interests serves as the fallback standard. To begin with the first of the five criteria, at the theoretical level, the model underlying the prevailing approach meets the criterion of logic and clarity. Brock has, for example, offered strategies for surmounting the apparent difficulty of accommodating persons who make advance directives and go on to develop a dementing disorder (such as Alzheimer disease), where a different self emerges that may bear little resemblance to the self that established the directive.[3] Apropos of the second criterion, advance directives in general, and Brock,s lexical model in particular, honor broad societal commitments to self-determination. But while ordering autonomy over well-being and justice may be consistent with the primacy typically afforded to self-determination many procedural matters such as contracts, wills, and in formed consent, putting autonomy ahead of other moral considerations makes it difficult to justify overriding advance directives ton grounds of well-being), or to honor the interests of others (on grounds of justice). While the possibility of justified overriding, alone seems to under mine the conventional approach on formal grounds, empirical data derived from situations in which trumping of advance directives actually occurs might inform theoretical work. In addition, the rate of trumping may be important. That is, if formal advance directives are often over ridden, they would be ineffectual on practical grounds. Similarly, both theoretical and empirical attention should address the extent to which the interests of others ought to influence decisionmaking for patients with and without decisional capacity. …