CanLegalRAGBench: Evaluating Retrieval-Augmented Generation on Canadian Case Law

Fuente: arXiv
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Hauptverfasser: Zhao, Ethan, Taranukhin, Maksym, Cui, Wei, Aikenhead, Moira, Shwartz, Vered
Format: Preprint
Veröffentlicht: 2026
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author Zhao, Ethan
Taranukhin, Maksym
Cui, Wei
Aikenhead, Moira
Shwartz, Vered
author_facet Zhao, Ethan
Taranukhin, Maksym
Cui, Wei
Aikenhead, Moira
Shwartz, Vered
contents RAG-based legal assistants have been growing in popularity, but LLM hallucinations remain a key issue and potentially undermines justice. While benchmarks have been developed to evaluate progress, many rely on synthetic queries rather than realistic legal scenarios. Moreover, Canadian law remains underrepresented in existing evaluations. To address this gap, we introduce CanLegalRAGBench, a Canadian legal QA benchmark based on realistic queries and expert-annotated answers grounded in case law. Our evaluation shows that retrieval performance is sensitive to design choices and that open-source embedding models are competitive with closed source models. However, it also reveals the limitation of automatic evaluations that penalize systems for retrieving alternative relevant documents. We also find that generated answers often diverge from gold responses, either with hallucinations or by producing overly detailed or irrelevant content, with 8-29% of claims not being supported by the retrieved documents. We hope this benchmark will help drive continued progress in addressing limitations of legal RAG systems.
format Preprint
id arxiv_https___arxiv_org_abs_2605_30497
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle CanLegalRAGBench: Evaluating Retrieval-Augmented Generation on Canadian Case Law
Zhao, Ethan
Taranukhin, Maksym
Cui, Wei
Aikenhead, Moira
Shwartz, Vered
Computation and Language
RAG-based legal assistants have been growing in popularity, but LLM hallucinations remain a key issue and potentially undermines justice. While benchmarks have been developed to evaluate progress, many rely on synthetic queries rather than realistic legal scenarios. Moreover, Canadian law remains underrepresented in existing evaluations. To address this gap, we introduce CanLegalRAGBench, a Canadian legal QA benchmark based on realistic queries and expert-annotated answers grounded in case law. Our evaluation shows that retrieval performance is sensitive to design choices and that open-source embedding models are competitive with closed source models. However, it also reveals the limitation of automatic evaluations that penalize systems for retrieving alternative relevant documents. We also find that generated answers often diverge from gold responses, either with hallucinations or by producing overly detailed or irrelevant content, with 8-29% of claims not being supported by the retrieved documents. We hope this benchmark will help drive continued progress in addressing limitations of legal RAG systems.
title CanLegalRAGBench: Evaluating Retrieval-Augmented Generation on Canadian Case Law
topic Computation and Language
url https://arxiv.org/abs/2605.30497