FaVe: Factored and Verified Search Rationale for Long-form Answer

Jihyuk Kim, Sungjin Lee, Seung-won Hwang, Yang Liu


Abstract
Targeting long-form question-answering, chain-of-query (CoQ) has been studied, integrating chain-of-thought (CoT) with retrieval-augmented generation. CoQ answers the complex question step-by-step, through simpler subquestions (SQs) from which relevant knowledge is retrieved. By doing so, CoQ aims to improve the answer comprehensiveness and verifiability, at the expense of latency. Our first contribution is showing that the chaining often incurs harmful effects on both objectives, and SQs left unverified often fail to answer the given question. Second, we propose a better alternative to CoQ, union-of-query which adopts a factored approach to break the harmful chain. Finally, we propose to verify SQs before answers, by fine-tuning the SQ generator using verified SQs and introducing a selector verifying SQs in test time. Employing vicuna-13b, our approach, denoted by FaVe (short for Factored and Verified search), even outperforms ChatGPT baselines while maintaining efficiency.
Anthology ID:
2025.findings-acl.993
Volume:
Findings of the Association for Computational Linguistics: ACL 2025
Month:
July
Year:
2025
Address:
Vienna, Austria
Editors:
Wanxiang Che, Joyce Nabende, Ekaterina Shutova, Mohammad Taher Pilehvar
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
19402–19416
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URL:
https://preview.aclanthology.org/landing_page/2025.findings-acl.993/
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Cite (ACL):
Jihyuk Kim, Sungjin Lee, Seung-won Hwang, and Yang Liu. 2025. FaVe: Factored and Verified Search Rationale for Long-form Answer. In Findings of the Association for Computational Linguistics: ACL 2025, pages 19402–19416, Vienna, Austria. Association for Computational Linguistics.
Cite (Informal):
FaVe: Factored and Verified Search Rationale for Long-form Answer (Kim et al., Findings 2025)
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https://preview.aclanthology.org/landing_page/2025.findings-acl.993.pdf