LOG: A Local-to-Global Optimization Approach for Retrieval-based Explainable Multi-Hop Question Answering

Hao Xu, Yunxiao Zhao, Jiayang Zhang, Zhiqiang Wang, Ru Li


Abstract
Multi-hop question answering (MHQA) aims to utilize multi-source intensive documents retrieved to derive the answer. However, it is very challenging to model the importance of knowledge retrieved. Previous approaches primarily emphasize single-step and multi-step iterative decomposition or retrieval, which are susceptible to failure in long-chain reasoning due to the progressive accumulation of erroneous information. To address this problem, we propose a novel Local-tO-Global optimized retrieval method (LOG) to discover more beneficial information, facilitating the MHQA. In particular, we design a pointwise conditional v-information based local information modeling to cover usable documents with reasoning knowledge. We also improve tuplet objective loss, advancing multi-examples-aware global optimization to model the relationship between scattered documents. Extensive experimental results demonstrate our proposed method outperforms prior state-of-the-art models, and it can significantly improve multi-hop reasoning, notably for long-chain reasoning.
Anthology ID:
2025.coling-main.610
Volume:
Proceedings of the 31st International Conference on Computational Linguistics
Month:
January
Year:
2025
Address:
Abu Dhabi, UAE
Editors:
Owen Rambow, Leo Wanner, Marianna Apidianaki, Hend Al-Khalifa, Barbara Di Eugenio, Steven Schockaert
Venue:
COLING
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
9085–9095
Language:
URL:
https://aclanthology.org/2025.coling-main.610/
DOI:
Bibkey:
Cite (ACL):
Hao Xu, Yunxiao Zhao, Jiayang Zhang, Zhiqiang Wang, and Ru Li. 2025. LOG: A Local-to-Global Optimization Approach for Retrieval-based Explainable Multi-Hop Question Answering. In Proceedings of the 31st International Conference on Computational Linguistics, pages 9085–9095, Abu Dhabi, UAE. Association for Computational Linguistics.
Cite (Informal):
LOG: A Local-to-Global Optimization Approach for Retrieval-based Explainable Multi-Hop Question Answering (Xu et al., COLING 2025)
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PDF:
https://aclanthology.org/2025.coling-main.610.pdf