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Main Authors: Zeng, Siqi, Jung, Christopher, Li, Rui, Kang, Zhe, Li, Ming, Noorshams, Nima, Wang, Zhigang, Peng, Fuchun, Zhao, Han, Feng, Xue
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2605.16704
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author Zeng, Siqi
Jung, Christopher
Li, Rui
Kang, Zhe
Li, Ming
Noorshams, Nima
Wang, Zhigang
Peng, Fuchun
Zhao, Han
Feng, Xue
author_facet Zeng, Siqi
Jung, Christopher
Li, Rui
Kang, Zhe
Li, Ming
Noorshams, Nima
Wang, Zhigang
Peng, Fuchun
Zhao, Han
Feng, Xue
contents Improving LLM performance on downstream tasks sometimes requires leveraging auxiliary datasets during post-training. In practice, however, developers face constraints on compute, labeling, and licensing costs that preclude using all available data, necessitating principled dataset-level selection. These constraints are increasingly shaped by dataset marketplaces, where data acquisition is governed by budgets and negotiation. We study dataset valuation as a subset selection problem during LLM post-training. Our goal is to identify and weight auxiliary datasets so as to maximize target task performance given constrained budgets. We first show that commonly used gradient alignment scores provide a reasonable yet incomplete valuation signal, as they ignore redundancy among datasets. To address this, we propose a scalable convex dataset-level valuation method based on kernel mean matching (KMM) in gradient space, which jointly accounts for alignment with the target task and redundancy across auxiliary datasets. Through extensive experiments across diverse post-training settings and tasks, we show that our approach consistently outperforms existing valuation baselines, achieving stronger performance with low computational overhead. Our results position dataset valuation as a practical decision tool for post-training data selection in market-constrained large language model settings. The code is available at https://github.com/uiuctml/convex_data_valuation.
format Preprint
id arxiv_https___arxiv_org_abs_2605_16704
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Convex Dataset Valuation for Post-Training
Zeng, Siqi
Jung, Christopher
Li, Rui
Kang, Zhe
Li, Ming
Noorshams, Nima
Wang, Zhigang
Peng, Fuchun
Zhao, Han
Feng, Xue
Machine Learning
Improving LLM performance on downstream tasks sometimes requires leveraging auxiliary datasets during post-training. In practice, however, developers face constraints on compute, labeling, and licensing costs that preclude using all available data, necessitating principled dataset-level selection. These constraints are increasingly shaped by dataset marketplaces, where data acquisition is governed by budgets and negotiation. We study dataset valuation as a subset selection problem during LLM post-training. Our goal is to identify and weight auxiliary datasets so as to maximize target task performance given constrained budgets. We first show that commonly used gradient alignment scores provide a reasonable yet incomplete valuation signal, as they ignore redundancy among datasets. To address this, we propose a scalable convex dataset-level valuation method based on kernel mean matching (KMM) in gradient space, which jointly accounts for alignment with the target task and redundancy across auxiliary datasets. Through extensive experiments across diverse post-training settings and tasks, we show that our approach consistently outperforms existing valuation baselines, achieving stronger performance with low computational overhead. Our results position dataset valuation as a practical decision tool for post-training data selection in market-constrained large language model settings. The code is available at https://github.com/uiuctml/convex_data_valuation.
title Convex Dataset Valuation for Post-Training
topic Machine Learning
url https://arxiv.org/abs/2605.16704