From Dissonance to Insights: Dissecting Disagreements in Rationale Construction for Case Outcome Classification

Shanshan Xu, Santosh T.y.s.s, Oana Ichim, Isabella Risini, Barbara Plank, Matthias Grabmair


Abstract
In legal NLP, Case Outcome Classification (COC) must not only be accurate but also trustworthy and explainable. Existing work in explainable COC has been limited to annotations by a single expert. However, it is well-known that lawyers may disagree in their assessment of case facts. We hence collect a novel dataset RaVE: Rationale Variation in ECHR, which is obtained from two experts in the domain of international human rights law, for whom we observe weak agreement. We study their disagreements and build a two-level task-independent taxonomy, supplemented with COC-specific subcategories. To our knowledge, this is the first work in the legal NLP that focuses on human label variation. We quantitatively assess different taxonomy categories and find that disagreements mainly stem from underspecification of the legal context, which poses challenges given the typically limited granularity and noise in COC metadata. We further assess the explainablility of state-of-the-art COC models on RaVE and observe limited agreement between models and experts. Overall, our case study reveals hitherto underappreciated complexities in creating benchmark datasets in legal NLP that revolve around identifying aspects of a case’s facts supposedly relevant for its outcome.
Anthology ID:
2023.emnlp-main.594
Volume:
Proceedings of the 2023 Conference on Empirical Methods in Natural Language Processing
Month:
December
Year:
2023
Address:
Singapore
Editors:
Houda Bouamor, Juan Pino, Kalika Bali
Venue:
EMNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
9558–9576
Language:
URL:
https://aclanthology.org/2023.emnlp-main.594
DOI:
10.18653/v1/2023.emnlp-main.594
Bibkey:
Cite (ACL):
Shanshan Xu, Santosh T.y.s.s, Oana Ichim, Isabella Risini, Barbara Plank, and Matthias Grabmair. 2023. From Dissonance to Insights: Dissecting Disagreements in Rationale Construction for Case Outcome Classification. In Proceedings of the 2023 Conference on Empirical Methods in Natural Language Processing, pages 9558–9576, Singapore. Association for Computational Linguistics.
Cite (Informal):
From Dissonance to Insights: Dissecting Disagreements in Rationale Construction for Case Outcome Classification (Xu et al., EMNLP 2023)
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PDF:
https://aclanthology.org/2023.emnlp-main.594.pdf
Video:
 https://aclanthology.org/2023.emnlp-main.594.mp4