The Area Under an ROC Curve

ROC curves can also be constructed from clinical prediction rules. The graphs at right come from a study of how clinical findings predict strep throat (Wigton RS, Connor JL, Centor RM. In that study, the presence of tonsillar exudate, fever, adenopathy and the absence of cough all predicted strep. The curves were constructed by computing the sensitivity and specificity of increasing numbers of clinical findings (from 0 to 4) in predicting strep. The study compared patients in Virginia and Nebraska and found that the rule performed more accurately in Virginia (area under the curve .78)