Turning failures into successes: a methodological shortcoming in empirical research on surrogate accuracy

Decision making for incompetent patients is a much-discussed topic in bioethics. According to one influential decision making standard, the substituted judgment standard, a surrogate decision maker ought to make the decision that the incompetent patient would have made, had he or she been competent. Empirical research has been conducted in order to find out whether surrogate decision makers are sufficiently good at doing their job, as this is defined by the substituted judgment standard. This research investigates to what extent surrogates are able to predict what the patient would have preferred in the relevant circumstances. In this paper we address a methodological shortcoming evident in a significant number of studies. The mistake consists in categorizing responses that only express uncertainty as predictions that the patient would be positive to treatment, on the grounds that the clinical default is to provide treatment unless it is refused. We argue that this practice is based on confusion and that it risks damaging the research on surrogate accuracy.