Optimized Oversampling

26 Sept 2024 (modified: 05 Feb 2025)Submitted to ICLR 2025EveryoneRevisionsBibTeXCC BY 4.0
Keywords: Machine Learning, Imbalanced Datasets, Optimization
Abstract: Many classification problems that arise in practice feature imbalanced datasets, a regime in which a lot of machine learning (ML) models show diminished performance. To address class imbalance, techniques like undersampling and oversampling are used to improve the model's performance. In this paper, we introduce a new oversampling framework, Optimized Oversampling ($O^{2}$), which generates synthetic minority class points by maximizing the probability of belonging to the minority class, which is estimated by a trained classification model. We show theoretically, under mild assumptions, that the points generated by $O^{2}$ are more likely to belong to the minority class than those generated by other approaches. Further, we benchmark $O^{2}$ against state-of-the-art oversampling methods on 16 publicly available imbalanced datasets using Classification Trees (CART) and Logistic Regression (LR) for the downstream classification task. The numerical experiments show that $O^{2}$ has an edge over current state-of-the-art oversampling methods, which is more pronounced on CART.
Supplementary Material: zip
Primary Area: optimization
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Submission Number: 8008
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