Formal measurement of clinical uncertainty: prelude to a trial in perinatal medicine

Abstract

Clinical trials are ethical when there is collective and balanced uncertainty about the best treatment among informed clinicians. This uncertainty can be identified either by observing differences in practice or, as explored here, by formal measurement of clinical belief. Fetomaternal medicine is largely concerned with timing delivery of preterm fetuses that are failing to thrive. Delivery is indicated when prematurity is judged preferable to continued intrauterine life, but often the relative risks of these alternatives are unknown.1 During the planning of a trial to compare early with delayed delivery under different circumstances 10 specialists in fetomaternal medicine were interviewed about their beliefs. The specialists were presented with four scenarios, one practice and three substantive, in each of which the decision between immediate and delayed delivery was difficult (see figure). They recorded their opinions on an analogue dial connected to a microcomputer. For each scenario respondents were asked what they thought the relative risk of permanent morbidity …