Study size The sample size calculation is based on published recommendations on effective sample sizes needed to validate prediction models. These recommendations are based on simulations of the sample sizes needed to detect statistically significant differences in predictive performance measures between two scores setting the power to 80% and the significance level to 5%. Hence, the required sample size was calculated to include the most recent 200 consecutive events, i.e. patients who died within 24 hours, and all non-events enrolled during the same time period. Mortality within 24 hours for was used for the sample size calculation as the investigators wanted the study to be powered for secondary outcomes also.