Retrieval–Reasoning Processes for Multi-hop Question Answering: A Four-Axis Design Framework and Empirical Trends

Yuelyu Ji, Zhuochun Li, Rui Meng, Daqing He


Abstract
Multi-hop question answering (QA) requires systems to iteratively retrieve evidence and reason across multiple hops. While recent RAG and agentic methods report strong results, the underlying retrieval–reasoning process is often left implicit, making procedural choices hard to compare across model families. This survey takes the execution procedure as the unit of analysis and introduces a four-axis framework covering overall execution plan, index structure, next-step control strategies and triggers, and stop/continue criteria. Using this schema, we map representative multi-hop QA systems and synthesize reported ablations and empirical tendencies on standard benchmarks, including HotpotQA, 2WikiMultiHopQA, and MuSiQue. We highlight recurring trade-offs among effectiveness, efficiency, and evidence faithfulness, and conclude with open challenges for retrieval–reasoning agents, including structure-aware planning, transferable control policies, and robust stopping under distribution shift.
Anthology ID:
2026.groundlm-1.7
Volume:
Proceedings of the 1st Workshop on Grounding Language Models: Learning Faithfully and Efficiently (GroundLM 2026)
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Yimu Wang, Yee Man Choi, Di Wu, Siqi Ouyang, Mozhgan Nasr Azadani, Yi R. (May) Fung
Venues:
GroundLM | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
84–103
Language:
URL:
https://aclanthology.org/2026.groundlm-1.7/
DOI:
Bibkey:
Cite (ACL):
Yuelyu Ji, Zhuochun Li, Rui Meng, and Daqing He. 2026. Retrieval–Reasoning Processes for Multi-hop Question Answering: A Four-Axis Design Framework and Empirical Trends. In Proceedings of the 1st Workshop on Grounding Language Models: Learning Faithfully and Efficiently (GroundLM 2026), pages 84–103, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Retrieval–Reasoning Processes for Multi-hop Question Answering: A Four-Axis Design Framework and Empirical Trends (Ji et al., GroundLM 2026)
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PDF:
https://aclanthology.org/2026.groundlm-1.7.pdf