There are substantial data establishing that surrogates are often mistaken in predicting what treatments incompetent patients would have wanted and that supplements such as advance directives have not resulted in significant improvements. Rid and Wendler's Patient Preference Predictor (PPP) proposal will attempt to gather data about what similar patients would prefer in a variety of treatment choices. It accepts the usual goal of patient autonomy and the Substituted Judgment principle for surrogate decisions. I provide reasons for questioning sole reliance on autonomy when surrogates, not patients, are deciding and for giving some independent weight to patient well-being. Moreover, that family members, typical surrogates, will know best what the patient if incompetent would have wanted is not the only reason why they are chosen. The more pressing problem is that the PPP would fail to remove the more serious mistakes that empirical psychology over the last few decades has shown to infect such decision making.
Keywords: surrogate decision making.