A Hybrid Framework for Precedent Reference Extraction

Arthur Elwing Torres, Johny Moreira, Daniela Vianna, Marina Ramalhete Masid, Celio Larcher, Edleno Silva de Moura, Altigran da Silva


Abstract
Legal documents frequently contain heterogeneous references to judicial precedents, making automated Precedent Reference Extraction (PRE) challenging for legal AI systems. Existing approaches rely heavily on LLM-based pipelines, which are often effective but also incur recurring prompting costs in high-volume production workloads and struggle with tracing extracted entities back to their character offsets in the source text. In light of these issues, we present Notarius, a domain-specific and production-ready hybrid framework that decomposes PRE into two stages: Overlapped NER Feature Extraction (ONFE), which extracts fine-grained precedent features, and Precedent Feature Aggregation (PFA), which reconstructs complete references for downstream applications. Our implementation integrates the Unified NER method W2NER with domain-specific heuristics. We evaluate Notarius at both feature and reference levels on a collection of judicial decisions and compare it in production against an LLM-based pipeline. Notarius achieves higher extraction quality, eliminates recurring LLM API costs for PRE, and provides span-level offset traceability. The system currently powers precedent extraction on Jusbrasil, demonstrating that discriminative, domain-specialized NER architectures remain valuable for cost-effective, high-precision legal information extraction in the LLM era.
Anthology ID:
2026.emnlp-industry.152
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing: Industry Track
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Pepa Atanasova, Gholamreza Haffari, Minghan Wang
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
2582–2590
Language:
URL:
https://aclanthology.org/2026.emnlp-industry.152/
DOI:
Bibkey:
Cite (ACL):
Arthur Elwing Torres, Johny Moreira, Daniela Vianna, Marina Ramalhete Masid, Celio Larcher, Edleno Silva de Moura, and Altigran da Silva. 2026. A Hybrid Framework for Precedent Reference Extraction. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing: Industry Track, pages 2582–2590, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
A Hybrid Framework for Precedent Reference Extraction (Torres et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-industry.152.pdf