Extractive Summarization of Legal Decisions using Multi-task Learning and Maximal Marginal Relevance

Abhishek Agarwal, Shanshan Xu, Matthias Grabmair


Abstract
Summarizing legal decisions requires the expertise of law practitioners, which is both time- and cost-intensive. This paper presents techniques for extractive summarization of legal decisions in a low-resource setting using limited expert annotated data. We test a set of models that locate relevant content using a sequential model and tackle redundancy by leveraging maximal marginal relevance to compose summaries. We also demonstrate an implicit approach to help train our proposed models generate more informative summaries. Our multi-task learning model variant leverages rhetorical role identification as an auxiliary task to further improve the summarizer. We perform extensive experiments on datasets containing legal decisions from the US Board of Veterans’ Appeals and conduct quantitative and expert-ranked evaluations of our models. Our results show that the proposed approaches can achieve ROUGE scores vis-à-vis expert extracted summaries that match those achieved by inter-annotator comparison.
Anthology ID:
2022.findings-emnlp.134
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2022
Month:
December
Year:
2022
Address:
Abu Dhabi, United Arab Emirates
Editors:
Yoav Goldberg, Zornitsa Kozareva, Yue Zhang
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
1857–1872
Language:
URL:
https://aclanthology.org/2022.findings-emnlp.134
DOI:
10.18653/v1/2022.findings-emnlp.134
Bibkey:
Cite (ACL):
Abhishek Agarwal, Shanshan Xu, and Matthias Grabmair. 2022. Extractive Summarization of Legal Decisions using Multi-task Learning and Maximal Marginal Relevance. In Findings of the Association for Computational Linguistics: EMNLP 2022, pages 1857–1872, Abu Dhabi, United Arab Emirates. Association for Computational Linguistics.
Cite (Informal):
Extractive Summarization of Legal Decisions using Multi-task Learning and Maximal Marginal Relevance (Agarwal et al., Findings 2022)
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PDF:
https://aclanthology.org/2022.findings-emnlp.134.pdf
Video:
 https://aclanthology.org/2022.findings-emnlp.134.mp4