Sampling Imbalanced Data with Multi-objective Bilevel Optimization

Fuente: arXiv
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Main Authors: Medlin, Karen, Leyffer, Sven, Raghavan, Krishnan
Format: Preprint
Published: 2025
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author Medlin, Karen
Leyffer, Sven
Raghavan, Krishnan
author_facet Medlin, Karen
Leyffer, Sven
Raghavan, Krishnan
contents Two-class classification problems are often characterized by an imbalance between the number of majority and minority datapoints resulting in poor classification of the minority class in particular. Traditional approaches, such as reweighting the loss function or naïve resampling, risk overfitting and subsequently fail to improve classification because they do not consider the diversity between majority and minority datasets. Such consideration is infeasible because there is no metric that can measure the impact of imbalance on the model. To obviate these challenges, we make two key contributions. First, we introduce MOODS~(Multi-Objective Optimization for Data Sampling), a novel multi-objective bilevel optimization framework that guides both synthetic oversampling and majority undersampling. Second, we introduce a validation metric -- `$ε/ δ$ non-overlapping diversification metric' -- that quantifies the goodness of a sampling method towards model performance. With this metric we experimentally demonstrate state-of-the-art performance with improvement in diversity driving a $1-15 \%$ increase in $F1$ scores.
format Preprint
id arxiv_https___arxiv_org_abs_2506_11315
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Sampling Imbalanced Data with Multi-objective Bilevel Optimization
Medlin, Karen
Leyffer, Sven
Raghavan, Krishnan
Machine Learning
Two-class classification problems are often characterized by an imbalance between the number of majority and minority datapoints resulting in poor classification of the minority class in particular. Traditional approaches, such as reweighting the loss function or naïve resampling, risk overfitting and subsequently fail to improve classification because they do not consider the diversity between majority and minority datasets. Such consideration is infeasible because there is no metric that can measure the impact of imbalance on the model. To obviate these challenges, we make two key contributions. First, we introduce MOODS~(Multi-Objective Optimization for Data Sampling), a novel multi-objective bilevel optimization framework that guides both synthetic oversampling and majority undersampling. Second, we introduce a validation metric -- `$ε/ δ$ non-overlapping diversification metric' -- that quantifies the goodness of a sampling method towards model performance. With this metric we experimentally demonstrate state-of-the-art performance with improvement in diversity driving a $1-15 \%$ increase in $F1$ scores.
title Sampling Imbalanced Data with Multi-objective Bilevel Optimization
topic Machine Learning
url https://arxiv.org/abs/2506.11315