Overlapping confidence intervals will be interpreted as evidence of lack of a statistically significant difference. Parametric and non-parametric exact tests will be used as appropriate, with 95% confidence intervals and a 5% significance level. The main analysis will be a complete case analysis, in which observations with missing values in any of the following variables will be excluded: time of arrival, age, sex, mechanism of injury, transfer status, and outcome variables. Observations with no injuries reported will be assigned ICISS scores of 1 and for each observation the final ICISS scores will be calculated based only on SRRs for ICD-codes that occur at least ten times in the published SRR-set used in this study.