Accuracy measures for stratified ROC analyses, using LOS to identify patients with resource use.*

*Data is reported as AUC (95% CI); **Adequate or higher discriminatory accuracy. Abbreviations: AUC = Area under the curve; COS = Critical Orthopaedic Surgery; DGA = Debridement under General Anaesthesia; ICISS = ICD-derived Injury Severity Score; ROC = Receiver operating characteristics. 1According to either serious injury or resource use definition; 2Defined as major surgery (such as brain or spine, thoracic, abdominal, neck, vascular, debridement under general anaesthesia, or critical orthopaedic surgery) or blood transfusion; 3Defined as ICISS