Brier Score.
The model’s overall performance is quantified by considering the distance between the actual outcome and the predicted outcome with better models have smaller distances5. The Brier score is used to calculate the model’s overall performance and is measured by calculating the squared differences between actual binary outcomes and predictions calculated by the model. The range of values that the Brier score of a model can take lies between 0 and 0.25 with 0 indicating a perfect model and 0.25 indicating a non-informative model with only a 50% incidence of the outcome2, 5. Brier score for survival outcome is not possible to calculate directly because of censoring. However, it is possible to calculate it indirectly defining a weight function that considers the conditional probability of being uncensored during the time. One disadvantage of the Brier score is that its interpretation depends on the incidence of the outcome with lower (higher) incidence corresponds to lower (higher) Brier score2.