Towards Better Legal Reasoning LLMs: Signal Balancing and Reward Scheduling

Yinghao Hu, Qian Xiao, Yuting Huang, Kaisong Song, Yiquan Wu, Ang Li, Junjie Cao, Jun Lin, Kun Kuang, Fei Wu


Abstract
In the legal domain, LLMs can improve reliability and interpretability by generating explicit reasoning traces. However, training LLMs to produce high-quality reasoning traces remains challenging. Existing supervised fine-tuning methods struggle when reasoning traces are significantly longer than final answers, as the learning signal for the answer becomes diluted. Meanwhile, reinforcement learning methods such as Group Relative Policy Optimization also have several limitations, including costly reward design, performance plateaus, and reward hacking. We therefore propose a two-stage training framework. In Stage I, JurisCoT-SFT employs a length-normalized dual objective to balance learning signals between reasoning traces and final answers. In Stage II, Lifecycle-Aware Backtrackable Policy Optimization dynamically evaluates and retires auxiliary reward signals based on their impact on final evaluation objectives, enabling efficient reward utilization. Our framework substantially improves legal reasoning performance on relevant tasks selected from multiple legal benchmarks, including ChJGBench, LawBench, and LegalBench. Experimental results demonstrate consistent improvements in both reasoning trace quality and final answer accuracy, while our models remain competitive with larger models.
Anthology ID:
2026.findings-emnlp.1273
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:
26924–26944
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1273/
DOI:
Bibkey:
Cite (ACL):
Yinghao Hu, Qian Xiao, Yuting Huang, Kaisong Song, Yiquan Wu, Ang Li, Junjie Cao, Jun Lin, Kun Kuang, and Fei Wu. 2026. Towards Better Legal Reasoning LLMs: Signal Balancing and Reward Scheduling. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 26924–26944, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Towards Better Legal Reasoning LLMs: Signal Balancing and Reward Scheduling (Hu et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1273.pdf