Exploring Selective Retrieval-Augmentation for Long-Tail Legal Text Classification

Fuente: arXiv
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Main Author: Mao, Boheng
Format: Preprint
Published: 2025
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author Mao, Boheng
author_facet Mao, Boheng
contents Legal text classification is a fundamental NLP task in the legal domain. Benchmark datasets in this area often exhibit a long-tail label distribution, where many labels are underrepresented, leading to poor model performance on rare classes. This paper explores Selective Retrieval-Augmentation (SRA) as a proof-of-concept approach to this problem. SRA focuses on augmenting samples belonging to low-frequency labels in the training set, preventing the introduction of noise for well-represented classes, and requires no changes to the model architecture. Retrieval is performed only from the training data to ensure there is no potential information leakage, removing the need for external corpora simultaneously. SRA is tested on two legal text classification benchmark datasets with long-tail distributions: LEDGAR (single-label) and UNFAIR-ToS (multi-label). Results show that SRA achieves consistent gains in both micro-F1 and macro-F1 over LexGLUE baselines.
format Preprint
id arxiv_https___arxiv_org_abs_2508_19997
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Exploring Selective Retrieval-Augmentation for Long-Tail Legal Text Classification
Mao, Boheng
Computation and Language
Information Retrieval
Legal text classification is a fundamental NLP task in the legal domain. Benchmark datasets in this area often exhibit a long-tail label distribution, where many labels are underrepresented, leading to poor model performance on rare classes. This paper explores Selective Retrieval-Augmentation (SRA) as a proof-of-concept approach to this problem. SRA focuses on augmenting samples belonging to low-frequency labels in the training set, preventing the introduction of noise for well-represented classes, and requires no changes to the model architecture. Retrieval is performed only from the training data to ensure there is no potential information leakage, removing the need for external corpora simultaneously. SRA is tested on two legal text classification benchmark datasets with long-tail distributions: LEDGAR (single-label) and UNFAIR-ToS (multi-label). Results show that SRA achieves consistent gains in both micro-F1 and macro-F1 over LexGLUE baselines.
title Exploring Selective Retrieval-Augmentation for Long-Tail Legal Text Classification
topic Computation and Language
Information Retrieval
url https://arxiv.org/abs/2508.19997