Early warning scores (EWS) were originally proposed by Morgan et al. to help identify patients who need immediate life-saving interventions, but not to predict their outcomes [1]. Ironically outcome prediction, rather than outcome improvement, has become a common metric of their performance [2,3]. EWS performance is most frequently reported as its ability to discriminate those patients who will develop an outcome from those who will not. Discrimination can be quantified by the area under the Receiver Operating Characteristic (ROC) curve (AUC).
