Towards Reliable Retrieval in RAG Systems for Large Legal Datasets

Fuente: arXiv
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Autori principali: Reuter, Markus, Lingenberg, Tobias, Liepiņa, Rūta, Lagioia, Francesca, Lippi, Marco, Sartor, Giovanni, Passerini, Andrea, Sayin, Burcu
Natura: Preprint
Pubblicazione: 2025
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author Reuter, Markus
Lingenberg, Tobias
Liepiņa, Rūta
Lagioia, Francesca
Lippi, Marco
Sartor, Giovanni
Passerini, Andrea
Sayin, Burcu
author_facet Reuter, Markus
Lingenberg, Tobias
Liepiņa, Rūta
Lagioia, Francesca
Lippi, Marco
Sartor, Giovanni
Passerini, Andrea
Sayin, Burcu
contents Retrieval-Augmented Generation (RAG) is a promising approach to mitigate hallucinations in Large Language Models (LLMs) for legal applications, but its reliability is critically dependent on the accuracy of the retrieval step. This is particularly challenging in the legal domain, where large databases of structurally similar documents often cause retrieval systems to fail. In this paper, we address this challenge by first identifying and quantifying a critical failure mode we term Document-Level Retrieval Mismatch (DRM), where the retriever selects information from entirely incorrect source documents. To mitigate DRM, we investigate a simple and computationally efficient technique which we refer to as Summary-Augmented Chunking (SAC). This method enhances each text chunk with a document-level synthetic summary, thereby injecting crucial global context that would otherwise be lost during a standard chunking process. Our experiments on a diverse set of legal information retrieval tasks show that SAC greatly reduces DRM and, consequently, also improves text-level retrieval precision and recall. Interestingly, we find that a generic summarization strategy outperforms an approach that incorporates legal expert domain knowledge to target specific legal elements. Our work provides evidence that this practical, scalable, and easily integrable technique enhances the reliability of RAG systems when applied to large-scale legal document datasets.
format Preprint
id arxiv_https___arxiv_org_abs_2510_06999
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Towards Reliable Retrieval in RAG Systems for Large Legal Datasets
Reuter, Markus
Lingenberg, Tobias
Liepiņa, Rūta
Lagioia, Francesca
Lippi, Marco
Sartor, Giovanni
Passerini, Andrea
Sayin, Burcu
Computation and Language
Information Retrieval
I.2.7; H.3.3; K.5.0
Retrieval-Augmented Generation (RAG) is a promising approach to mitigate hallucinations in Large Language Models (LLMs) for legal applications, but its reliability is critically dependent on the accuracy of the retrieval step. This is particularly challenging in the legal domain, where large databases of structurally similar documents often cause retrieval systems to fail. In this paper, we address this challenge by first identifying and quantifying a critical failure mode we term Document-Level Retrieval Mismatch (DRM), where the retriever selects information from entirely incorrect source documents. To mitigate DRM, we investigate a simple and computationally efficient technique which we refer to as Summary-Augmented Chunking (SAC). This method enhances each text chunk with a document-level synthetic summary, thereby injecting crucial global context that would otherwise be lost during a standard chunking process. Our experiments on a diverse set of legal information retrieval tasks show that SAC greatly reduces DRM and, consequently, also improves text-level retrieval precision and recall. Interestingly, we find that a generic summarization strategy outperforms an approach that incorporates legal expert domain knowledge to target specific legal elements. Our work provides evidence that this practical, scalable, and easily integrable technique enhances the reliability of RAG systems when applied to large-scale legal document datasets.
title Towards Reliable Retrieval in RAG Systems for Large Legal Datasets
topic Computation and Language
Information Retrieval
I.2.7; H.3.3; K.5.0
url https://arxiv.org/abs/2510.06999