Data-Efficient Selection via Grammatical Complexity in Continual Pre-training of Domain-Specific LLMs

Yizhou Ying, Geng Zhang, Cui Danxin, Chengyu Du, Guanglei Yue, Sihang Jiang, Jiaqing Liang, Yifei Fu, Hailin Hu, Yanghua Xiao


Abstract
Data efficiency is crucial in domain-specific continual pre-training (CPT) of large language models (LLMs), especially under resource constraints. Aiming for “small data, big impact,” this work addresses the limitations of existing domain-specific data selection strategies, which often rely on scarce labeled data or computationally expensive LLMs. We introduce CDF Sampling with Grammatical Complexity (CDF-GC), an annotation-independent, efficient and interpretable data selection framework for CPT. Our approach comprehensively evaluates grammatical complexity using lexical diversity and syntactic complexity, and employs a cumulative distribution function (CDF)-based sampling strategy to balance complexity and diversity. To validate the effectiveness of CDF-GC, we conducted experiments on a financial dataset. The results demonstrate that CDF-GC significantly outperforms baselines, achieving 2.0% improvement in financial QA at the same selection ratio and even surpassing full-data training by 1.7% using only 20% of the data.
Anthology ID:
2025.emnlp-main.1121
Volume:
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Month:
November
Year:
2025
Address:
Suzhou, China
Editors:
Christos Christodoulopoulos, Tanmoy Chakraborty, Carolyn Rose, Violet Peng
Venue:
EMNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
22066–22080
Language:
URL:
https://preview.aclanthology.org/author-page-yu-wang-polytechnic/2025.emnlp-main.1121/
DOI:
10.18653/v1/2025.emnlp-main.1121
Bibkey:
Cite (ACL):
Yizhou Ying, Geng Zhang, Cui Danxin, Chengyu Du, Guanglei Yue, Sihang Jiang, Jiaqing Liang, Yifei Fu, Hailin Hu, and Yanghua Xiao. 2025. Data-Efficient Selection via Grammatical Complexity in Continual Pre-training of Domain-Specific LLMs. In Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing, pages 22066–22080, Suzhou, China. Association for Computational Linguistics.
Cite (Informal):
Data-Efficient Selection via Grammatical Complexity in Continual Pre-training of Domain-Specific LLMs (Ying et al., EMNLP 2025)
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PDF:
https://preview.aclanthology.org/author-page-yu-wang-polytechnic/2025.emnlp-main.1121.pdf
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