For some models, resampling strategy A (patient level sampling) tends to over-estimate model performance, compared to sampling strategy B (PCR batch level sampling). Panel A presents the cross-validated AUC at day 7 for all the prognostic models, using resampling strategy A. The cross-validated AUC is estimated using the pooling method (y-axis) and the averaging method (x-axis); red dots correspond to AUC estimations based on the predicted survival and black dots to AUC estimations based on the linear predictor (see Methods section). Panel B presents the cross-validated AUC at day 7 for all the prognostic models, using resampling strategy B. Finally, panel C compares the cross-validated AUC estimated with strategy A (x-axis) vs. strategy B (y-axis), using the pooling method based on the linear predictor.