Labor Lex: A New Portuguese Corpus and Pipeline for Information Extraction in Brazilian Legal Texts

Pedro Vitor Quinta de Castro, Nádia Félix Felipe Da Silva


Abstract
Relation Extraction (RE) is a challenging Natural Language Processing task that involves identifying named entities from text and classifying the relationships between them. When applied to a specific domain, the task acquires a new layer of complexity, handling the lexicon and context particular to the domain in question. In this work, this task is applied to the Legal domain, specifically targeting Brazilian Labor Law. Architectures based on Deep Learning, with word representations derived from Transformer Language Models (LM), have shown state-of-the-art performance for the RE task. Recent works on this task handle Named Entity Recognition (NER) and RE either as a single joint model or as a pipelined approach. In this work, we introduce Labor Lex, a newly constructed corpus based on public documents from Brazilian Labor Courts. We also present a pipeline of models trained on it. Different experiments are conducted for each task, comparing supervised training using LMs and In-Context Learning (ICL) with Large Language Models (LLM), and verifying and analyzing the results for each one. For the NER task, the best achieved result was 89.97% F1-Score, and for the RE task, the best result was 82.38% F1-Score. The best results for both tasks were obtained using the supervised training approach.
Anthology ID:
2025.nllp-1.14
Volume:
Proceedings of the Natural Legal Language Processing Workshop 2025
Month:
November
Year:
2025
Address:
Suzhou, China
Editors:
Nikolaos Aletras, Ilias Chalkidis, Leslie Barrett, Cătălina Goanță, Daniel Preoțiuc-Pietro, Gerasimos Spanakis
Venues:
NLLP | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
184–206
Language:
URL:
https://preview.aclanthology.org/ingest-emnlp/2025.nllp-1.14/
DOI:
Bibkey:
Cite (ACL):
Pedro Vitor Quinta de Castro and Nádia Félix Felipe Da Silva. 2025. Labor Lex: A New Portuguese Corpus and Pipeline for Information Extraction in Brazilian Legal Texts. In Proceedings of the Natural Legal Language Processing Workshop 2025, pages 184–206, Suzhou, China. Association for Computational Linguistics.
Cite (Informal):
Labor Lex: A New Portuguese Corpus and Pipeline for Information Extraction in Brazilian Legal Texts (Quinta de Castro & Da Silva, NLLP 2025)
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PDF:
https://preview.aclanthology.org/ingest-emnlp/2025.nllp-1.14.pdf