LegalReasoner: Step-wised Verification-Correction for Legal Judgment Reasoning
Paper · 2025 · Weijie Shi, Han Zhu, Jiaming Ji et al.
Summary
Legal judgment prediction (LJP) asks a model to produce a court-like ruling from a plaintiff's claim and the case facts. LLMs often make logical mistakes when a case needs multi-step legal analysis. The authors propose LegalReasoner, which first identifies a case's dispute points and then reasons toward a verdict one step at a time. A process verifier rates every step on correctness, progressiveness and potential. When a step falls short, a classifier assigns the flaw to an error type defined by legal experts, such as misapplying a legal principle or reasoning that conflicts with the facts. A matching remedy then runs, for example retrieving provisions and precedents or tracking facts. To train the system, the authors built LegalHK, a corpus of Hong Kong court decisions annotated with disputes, reasoning chains and step-level verification labels. The annotations were extracted mainly with GPT-4 and screened by judicial experts. On LLAMA-3.1-70B, agreement with real court outcomes rises from 72.37 to 80.27. The work shows that step-level supervision, previously used mostly for math and code, can carry over to legal reasoning.
Key points
- LegalHK contains 58,130 Hong Kong cases, filtered from 185,495 decisions dated 1900–2023 and scraped from HKLII. It is released on Hugging Face as
weijiezz/LegalHK. - Decisions from the Court of Final Appeal and the Court of Appeal were excluded, since the official descriptions of such cases tend to be shortened and lack detail. Before GPT-4 structuring, documents were compressed to roughly one-third to one-half of their original length.
- Fact descriptions were checked by GPT-4 and by judicial experts so that they do not reveal the final verdict.
- The verifier scores each step on three criteria: correctness, progressiveness and potential. Detected errors are routed to expert-designed attribution and resolution strategies.
- The authors list three limitations:
- Step-wise checking is computationally expensive, though they report it beats Best-of-N sampling at lower cost.
- The automatically generated verifier labels are noisy.
- How well the approach transfers to other legal systems remains open.
Institutions
Fields, topics and concepts
📚 Shelves 7The field of science this work belongs to (OpenAlex fields).Computer Science · 16,667 worksArtificial Intelligence · 16,194 worksArts and Humanities · 16,039 worksLanguage and Linguistics · 15,891 worksSocial Sciences · 1,772 worksPolitical Science and International Relations · 182 worksLaw · 77 works
🧭 Topics 2Research subjects and languages the work is about.Reasoning · 1,426 worksLegal AI · 134 works
Cite
Cite as Weijie Shi, Han Zhu, Jiaming Ji, Mengze Li, Jipeng Zhang, Ruiyuan Zhang, Jia Zhu, Jiajie Xu, Sirui Han and Yike Guo. 2025. LegalReasoner: Step-wised Verification-Correction for Legal Judgment Reasoning. Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers).
@inproceedings{shi2025legalreasoner,
title = {{LegalReasoner: Step-wised Verification-Correction for Legal Judgment Reasoning}},
author = {Weijie Shi, Han Zhu, Jiaming Ji, Mengze Li, Jipeng Zhang, Ruiyuan Zhang, Jia Zhu, Jiajie Xu, Sirui Han and Yike Guo},
booktitle = {Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)},
year = {2025},
doi = {10.18653/v1/2025.acl-long.361},
url = {https://doi.org/10.18653/v1/2025.acl-long.361}
}References
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