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Main Authors: Du, Zilin, Zhao, Junqi, Li, Boyang Albert
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2606.00571
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author Du, Zilin
Zhao, Junqi
Li, Boyang Albert
author_facet Du, Zilin
Zhao, Junqi
Li, Boyang Albert
contents Synthetic data are increasingly used to train neural networks, yet distributional mismatch with real data limits their effectiveness when used indiscriminately. A common strategy is to learn data weights via bi-level optimization, which we refer to as Meta-learning for Training-data Selection (MTS). Interestingly, in practice, MTS often performs below expectation. We identify two obstacles in properly training MTS: a poor gradient signal-to-noise ratio (GSNR), which causes optimization difficulties, and lack of informative features that correlates with data quality. We present a mathematical analysis of MTS, which reveals the dynamics of normalized data weights and the relation between disparate data quality and poor GSNR. The analysis suggests a a simple yet effective solution: increasing the batch size. Further, we propose a set of informative features that capture the positions of training data in their distributions and training dynamics. Experiments across four benchmarks show consistent improvements, achieving average gains of 5.49% over training without selection and 2.89% over the strongest baseline.
format Preprint
id arxiv_https___arxiv_org_abs_2606_00571
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle On the Difficulty of Learning a Meta-network for Training Data Selection
Du, Zilin
Zhao, Junqi
Li, Boyang Albert
Machine Learning
Artificial Intelligence
Computer Vision and Pattern Recognition
Synthetic data are increasingly used to train neural networks, yet distributional mismatch with real data limits their effectiveness when used indiscriminately. A common strategy is to learn data weights via bi-level optimization, which we refer to as Meta-learning for Training-data Selection (MTS). Interestingly, in practice, MTS often performs below expectation. We identify two obstacles in properly training MTS: a poor gradient signal-to-noise ratio (GSNR), which causes optimization difficulties, and lack of informative features that correlates with data quality. We present a mathematical analysis of MTS, which reveals the dynamics of normalized data weights and the relation between disparate data quality and poor GSNR. The analysis suggests a a simple yet effective solution: increasing the batch size. Further, we propose a set of informative features that capture the positions of training data in their distributions and training dynamics. Experiments across four benchmarks show consistent improvements, achieving average gains of 5.49% over training without selection and 2.89% over the strongest baseline.
title On the Difficulty of Learning a Meta-network for Training Data Selection
topic Machine Learning
Artificial Intelligence
Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2606.00571