Subjective Expected Utility and Referral Decisions in Obesity

Abstract

SummaryReferral decisions of physicians dealing with long-term ambulatory problems are complex phenomena that are not clearly understood. This study was designed to assess the possible rationale behind such decisions in the management of obesity. It examined how well a subjective expected utility (SEU) model accounted for decisions of 45 primary care physicians regarding referral of obese female patients to an endocrinologist. Two patient goals, weight reduction and patient satisfaction, and a two-year time horizon were incorporated in the model.Data were collected using 24 written cases representing 12 patients approximately 100% overweight and 12 about 50% overweight, and a semi-structured interview in which subjective probabilities and importance weights were obtained. Values were calculated by transforming physicians’ ratings of risk of morbidity in the 24 cases into a utility scale.The SEU did not account for the primary care physicians’ referral behavior. Correlations between number of patient cases referred and SEU were analyzed and were not statistically significant, although there was substantial variation across physicians in number of cases referred. Mean subjective probabilities of weight loss and patient satisfaction were essentially identical for referral and non-referral.The formulation of the model, the design of the cases, and the method of value assessment are discussed as potential threats to the validity of the model as an account of referral decisions. Problems of constructing an adequate model are considered.