Figure 4.

Discrimination and calibration of the multivariate outcome prediction model. (a) Discrimination. Receiver operating characteristic curve of the multivariate outcome prediction model based on base deficit, Glasgow Coma Scale score, prothrombin time, age and Injury Severity Score, compared with that derived from the Trauma and Injury Severity Score (TRISS) in the validation set of 1745 multiple trauma patients. The diagonal line corresponds to a test that is sensitive or specific just by chance. The area under the curve for the multivariate outcome prediction model is 0.901 and that for the TRISS score is 0.866. (b) Calibration. Predicted versus observed mortality for the multivariate outcome prediction model and the TRISS score in the validation set of 1745 multiple trauma patients.