Of bombers, radiologists, and cardiologists: time to ROC

Editor,—Dr Collinson suggests that it is time that cardiologists use the ROC (receiver operator characteristic) curve and that it “avoids the pitfalls of sensitivity and specificity”.1 While the ROC curve is undoubtedly useful in describing the performance of a test and in comparing tests, I find the claim a little surprising as the ROC curve is simply a series of sensitivities and specificities with the cut off sweeping from minimum sensitivity to minimum specificity. Second, it is recommended that the “point of maximum curvature” is chosen as the optimum trade off between sensitivity and specificity. This is true if the costs of false positives and false negatives are equal—but only if these are equal, which …