Towards Efficient Chain-of-Thought Reasoning via Adaptive-Budgeting based Policy Optimization

Wenhao Lin, Qiong Wu, Shuaixiang Yang, Yiyi Zhou, Hui Li, Kehai Chen, Xiaoshuai Sun, Rongrong Ji


Abstract
Chain-of-Thought (CoT) reasoning has become a key problem-solving capability for advanced large language models (LLMs), but the "over-thinking" issue still plagues LLMs. In this paper, we propose a novel learning scheme termed Adaptive-Budgeting based Policy Optimization (ABPO) to balance the performance and efficiency of CoT reasoning. Our ABPO defines the RL training as an adaptive curriculum learning process, where example pools are curated to categorize training examples into three types, namely the mastered, learning and hard ones, respectively. As the training progresses, ABPO will adaptively schedule the examples with proper length budgets, and the example pools will also be dynamically updated based on the model status, thereby achieving a good balance between efficiency and performance of CoTs. The experimental results not only show the substantial efficiency improvements by ABPO, e.g., reducing token length by 78.3% while improving 2.0% performance of DeepSeek-R1-Distill-Qwen-1.5B on average, but also show its obvious advantages over the compared methods, e.g., reducing 59.4% length and increasing 8.3% performance on average than HAPO, respectively. Our code is released at https://github.com/SenriAkane1/ABPO/
Anthology ID:
2026.findings-emnlp.1050
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
22223–22265
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URL:
https://aclanthology.org/2026.findings-emnlp.1050/
DOI:
Bibkey:
Cite (ACL):
Wenhao Lin, Qiong Wu, Shuaixiang Yang, Yiyi Zhou, Hui Li, Kehai Chen, Xiaoshuai Sun, and Rongrong Ji. 2026. Towards Efficient Chain-of-Thought Reasoning via Adaptive-Budgeting based Policy Optimization. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 22223–22265, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Towards Efficient Chain-of-Thought Reasoning via Adaptive-Budgeting based Policy Optimization (Lin et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1050.pdf