Christopher Andreas

Credit Card Fraud Detection under Extreme Class Imbalance: A Comparison of KNN and Logistic Regression

The main finding is that under severe imbalance ROC-AUC can be misleading and PR-AUC is more informative; KNN baseline is a balanced detector without tuning, threshold-tuned LR baseline gives the best single operating point, and LR+SMOTE suits cases where recall is the priority.