Beyond Correctness: A Framework for Analyzing Reasoning and Faithfulness of Multi-hop Question Answering

Jiyuan Liu, Yi Xie, Yanghui Rao, Fu Lee Wang, Jianxing Yu, Li Qing


Abstract
Diagnosing the root causes of failures in Retrieval-Augmented Generation (RAG) is challenging, as current evaluations often conflate logical reasoning errors with the failure to adhere to retrieved context. To address this, we propose **ReFa**, a framework inspired by Structural Causal Models to explicitly disentangle *Reasoning* from *Faithfulness*. Through this lens, we characterize two distinct failure modes: the **‘Fool’**, representing a deficiency in logical reasoning, and the **‘Lazy’**, representing a lapse in faithfulness where the model defaults to parametric priors. To operationalize this diagnosis, we introduce Dual Reasoning Chain Editing, a mechanism that constructs controlled proxy chains to isolate reasoning structure from evidence faithfulness. We apply this method on **ReFaBench**, a novel benchmark constructed in this work featuring factual, counterfactual, and knowledge-conflicting scenarios. Furthermore, we propose **ReFa-DPO**, a decoupled preference optimization strategy that leverages these proxies to target specific failure patterns. Experimental results demonstrate that **ReFa-DPO** enhances robustness, particularly in mitigating parametric interference, by simultaneously enhancing both contextual faithfulness and reasoning capabilities.
Anthology ID:
2026.findings-aacl.135
Volume:
Findings of the Association for Computational Linguistics: IJCNLP-AACL 2026
Month:
November
Year:
2026
Address:
Hengqin, China
Editors:
Yue Zhang, Ruifeng Xu, Ayu Purwarianti, Tong Rong, Jun Suzuki
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
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Pages:
2628–2648
Language:
URL:
https://aclanthology.org/2026.findings-aacl.135/
DOI:
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Cite (ACL):
Jiyuan Liu, Yi Xie, Yanghui Rao, Fu Lee Wang, Jianxing Yu, and Li Qing. 2026. Beyond Correctness: A Framework for Analyzing Reasoning and Faithfulness of Multi-hop Question Answering. In Findings of the Association for Computational Linguistics: IJCNLP-AACL 2026, pages 2628–2648, Hengqin, China. Association for Computational Linguistics.
Cite (Informal):
Beyond Correctness: A Framework for Analyzing Reasoning and Faithfulness of Multi-hop Question Answering (Liu et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-aacl.135.pdf