Figure 7:

Pictorial summary of the study demonstrating the effect of imbalanced data on the outcome of a Random Forest (RF) classifier. Method: 92% of the 800 patients used in this study to test the RF classifier survived to 90 days and only 8% of patients were dead at 90 days. Result: The plot of predicted probabilities by RF categorized by their real labels illustrates the issues of imbalance and overlap of the two classes. Evaluation of Results: While Receiver operating characteristic (ROC) indicated an acceptable performance for RF (AUC= 0.77), the Precision Recall Curve (PRC) revealed moderate performance (AUC= 0.43).