Use of certainty of opinion data to enhance clinical decision making

Clinical decision making and diagnostic testing procedures are frequently evaluated using indices such as sensitivity and specificity. These indices require an assumption that the underlying disease state or the diagnostic test result is binary, which may be an unreasonable assumption in many clinical situations. They also fail to recognise the potential for different degrees of diagnostic confidence. In this paper, we report some data from a clinical study of postpartum mothers in which, in addition to the diagnostic result, an expression of certainty or strength of belief was ascertained. We illustrate how the certainty of opinion data can be combined with the diagnostic opinion in order to enhance the interpretation of the study, and the implications for improving the accuracy of clinical decision making in general.