This function subtracts integrated the C/D AUC metric from one to obtain a loss function whose lower values indicate better model performance (useful for permutational feature importance)
loss_one_minus_integrated_cd_auc( y_true =NULL, risk =NULL, surv =NULL, times =NULL)
Arguments
y_true: a survival::Surv object containing the times and statuses of observations for which the metric will be evaluated
risk: ignored, left for compatibility with other metrics
surv: a matrix containing the predicted survival functions for the considered observations, each row represents a single observation, whereas each column one time point
times: a vector of time points at which the survival function was evaluated
Returns
numeric from 0 to 1, lower values indicate better performance
#' @section References:
[1] Uno, Hajime, et al. "Evaluating prediction rules for t-year survivors with censored regression models." Journal of the American Statistical Association 102.478 (2007): 527-537.
[2] Hung, Hung, and Chin‐Tsang Chiang. "Optimal composite markers for time‐dependent receiver operating characteristic curves with censored survival data." Scandinavian Journal of Statistics 37.4 (2010): 664-679.
Examples
library(survival)library(survex)cph <- coxph(Surv(time, status)~ ., data = veteran, model =TRUE, x =TRUE, y =TRUE)cph_exp <- explain(cph)y <- cph_exp$y
times <- cph_exp$times
surv <- cph_exp$predict_survival_function(cph, cph_exp$data, times)# calculating directlyloss_one_minus_integrated_cd_auc(y, surv = surv, times = times)