FIG A2.

For an operation in the holdout test set, the SHAP values showing top contributing features to the prediction of 30-day Clavien-Dindo grade 3 or higher postoperative complications. The red color represents features that increase the likelihood of complication, whereas the blue color represents features that reduce the likelihood of complication. The size of each arrow bar indicates the magnitude of the feature contribution on the basis of the SHAP value of the feature. The base value is 0.24, which represents the mean of predicted scores in the holdout test set. In this example of a patient scheduled for an operation, the risk score is 0.74 (shown in bold). The top four features contributing to the risk of a complication in this patient are labeled in red. SHAP, Shapley additive explanations.