Validator-Guided Decoding for Multi-Hop Knowledge Editing

Shanbao Qiao, Xuebing Liu, Seung-Hoon Na


Abstract
Knowledge editing aims to update specific factual knowledge in large language models without full retraining. Although existing editors can often modify local factual associations, edited models still struggle to apply updated knowledge in multi-hop reasoning. In this work, we study this problem through the lens of the generate-verification gap: a model may fail to directly generate the correct updated answer, while a verifier conditioned on the edit facts can still judge whether a proposed answer is compatible with the updated knowledge. Motivated by this observation, we propose Validator-Guided Decoding (VGD), a test-time method that uses edit facts as verification memory to improve answer generation after knowledge editing. VGD employs a trained validator as an external correctness signal over candidate answers, allowing the model to retain reliable outputs while selectively revising uncertain or inconsistent predictions. It is editor-agnostic and can be applied to base models or on top of existing editors without modifying the editor or further updating the edited model. Experiments on multi-hop benchmarks show that VGD improves hop-level consistency and final-answer accuracy, generally outperforming ICL and CoT baselines. Our code will be available at https://github.com/JoveReCode/VGD.
Anthology ID:
2026.emnlp-main.454
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
10433–10449
Language:
URL:
https://aclanthology.org/2026.emnlp-main.454/
DOI:
Bibkey:
Cite (ACL):
Shanbao Qiao, Xuebing Liu, and Seung-Hoon Na. 2026. Validator-Guided Decoding for Multi-Hop Knowledge Editing. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 10433–10449, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Validator-Guided Decoding for Multi-Hop Knowledge Editing (Qiao et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.454.pdf