Assessment of diagnostic accuracy in caries detection: an analysis of two methods

The quality of a diagnostic tool for caries detection is usually evaluated by quantification of observer performance using sensitivity and specificity values calculated from data obtained from ordinal caries depth rating scales. The application of Receiver Operating Characteristic (ROC) analysis has been restricted to the use of confidence rating scales. The aim of this investigation was to study the appropriateness of ROC analysis using caries depth ratings by comparing sensitivity and specificity values to parameters of diagnostic performance obtained by ROC analysis. In two recent reports, sensitivity and specificity values were utilized to express diagnostic accuracy of observer performance from specified caries diagnostic systems. The raw data from these investigations were subjected to ROC analysis in the current study. The results illustrated that ROC analysis, producing estimates of sensitivities for all specificities, yielded more comprehensive measures of diagnostic performance than single values for sensitivity and specificity. In particular, the area under the ROC curve constituted a clearly interpretable parameter representing the quality of diagnostic performance.