Citation-Closure Retrieval and Per-Rule Attribution for Real-World Regulatory Compliance Question Answering

Yeong-Joon Ju, Seong-Whan Lee


Abstract
Deploying Large Language Models (LLMs) for regulatory compliance demands rigorous traceability via comprehensive citations across multi-tiered authority structures. Unlike traditional multi-hop or legal QA, this task requires structured procedural lookups and evidence-set closure rather than entity resolution or case-law reasoning. Existing RAG systems struggle here due to flattened citation edges, fragmented retrieval expansions, and fragile post-hoc attribution. We formalize Regulatory Compliance QA with RegOps-Bench, a novel benchmark featuring an Operational Knowledge Graph derived from complex national R&D regulations. To address these bottlenecks, we propose RefWalk, a unified framework driven by a shared topic anchor. RefWalk traverses cross-document citations, fuses multi-view candidates via max-based aggregation, and enforces per-rule attribution to explicitly map claims to sources. We establish a strong baseline with substantial improvements in retrieval recall and citation accuracy. Finally, a contrastive evaluation on a U.S. health compliance dataset (HIPAA) reveals that existing systems exhibit saturation on flat-structure rules, underscoring the need for RegOps-Bench. Our code is available at https://github.com/yeongjoonJu/RefWalk.
Anthology ID:
2026.findings-emnlp.776
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
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SIGDAT
Publisher:
Association for Computational Linguistics
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Pages:
16401–16426
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URL:
https://aclanthology.org/2026.findings-emnlp.776/
DOI:
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Cite (ACL):
Yeong-Joon Ju and Seong-Whan Lee. 2026. Citation-Closure Retrieval and Per-Rule Attribution for Real-World Regulatory Compliance Question Answering. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 16401–16426, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Citation-Closure Retrieval and Per-Rule Attribution for Real-World Regulatory Compliance Question Answering (Ju & Lee, Findings 2026)
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https://aclanthology.org/2026.findings-emnlp.776.pdf