Sensitivity, Specificity, and Predictive Values in the 'Sensitivity and Specificity of Clinical Diagnostics'

To the Editor.—  The article concerning postmortem evaluation of clinical diagnostics during five decades¹ is a good effort to analyze disparate data that can be resistant to marshaling by ordinary statistical methods. However, I think that the true-negative category, within the constraints of this study, is largely a passive statistic that sheds little light on the diagnostic process. This occurs because the act of making a clinical diagnosis leads to a mutually exclusive binomial distribution of that diagnosis vs a statistical universe of other diagnoses, many of which are trivial. On the other hand, "agreed" (true positives), "underdiagnosed" (false negatives), and "overdiagnosed" (false positives) are intuitively satisfying categories that present a more realistic picture of actual practice.Another statistical method avoids the true-negative dilemma by using only those cells of the fourfold (2 × 2) tables that can be occupied by at least one positive diagnosis (clinical or autopsy).