Papers › Rethinking the Value of Labels for Improving Class-Imbalanced Learning

Rethinking the Value of Labels for Improving Class-Imbalanced Learning

13 Jun 2020NeurIPS 2020 12arXiv:2006.07529archive 2025-07-28

Yuzhe Yang, Zhi Xu

Real-world data often exhibits long-tailed distributions with heavy class imbalance, posing great challenges for deep recognition models. We identify a persisting dilemma on the value of labels in the context of imbalanced learning: on the one hand, supervision from labels typically leads to better results than its unsupervised counterparts; on the other hand, heavily imbalanced data naturally incurs "label bias" in the classifier, where the decision boundary can be drastically altered by the majority classes. In this work, we systematically investigate these two facets of labels. We demonstrate, theoretically and empirically, that class-imbalanced learning can significantly benefit in both semi-supervised and self-supervised manners. Specifically, we confirm that (1) positively, imbalanced labels are valuable: given more unlabeled data, the original labels can be leveraged with the extra data to reduce label bias in a semi-supervised manner, which greatly improves the final classifier; (2) negatively however, we argue that imbalanced labels are not useful always: classifiers that are first pre-trained in a self-supervised manner consistently outperform their corresponding baselines. Extensive experiments on large-scale imbalanced datasets verify our theoretically grounded strategies, showing superior performance over previous state-of-the-arts. Our intriguing findings highlight the need to rethink the usage of imbalanced labels in realistic long-tailed tasks. Code is available at https://github.com/YyzHarry/imbalanced-semi-self.

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Tasks

Long-tail Learning

Results from the paper archive 2025-07-28

TaskDatasetModelMetricValueRank at snapshotLeaderboardReport
Long-tail Learning CIFAR-10-LT (ρ=10) LDAM-DRW + SSP Error Rate 11.47 #35 of 50 Archive leaderboard report
Long-tail Learning CIFAR-10-LT (ρ=100) LDAM-DRW + SSP Error Rate 22.17 #26 of 28 Archive leaderboard report
Long-tail Learning CIFAR-100-LT (ρ=10) LDAM-DRW + SSP Error Rate 41.09 #27 of 31 Archive leaderboard report
Long-tail Learning CIFAR-100-LT (ρ=100) LDAM-DRW + SSP Error Rate 56.57 #57 of 66 Archive leaderboard report
Long-tail Learning CIFAR-100-LT (ρ=50) LDAM-DRW + SSP Error Rate 52.89 #25 of 25 Archive leaderboard report
Long-tail Learning ImageNet-LT cRT + SSP Top-1 Accuracy 51.3 #53 of 69 Archive leaderboard report
Long-tail Learning iNaturalist 2018 cRT + SSP Top-1 Accuracy 68.1% #39 of 43 Archive leaderboard report

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