SVote-2S: Input-Side Evidence Voting for Two-Stage Self-Consistency in Multi-Hop QA

Guo Ouyang, Ge Wang, Tao Zhu, Yi Zou, Xuehao Yin, Guoliang Li, Fuchuan Ni


Abstract
Self-consistency (SC) improves chain-of-thought reasoning by aggregating multiple sampled answers, yet all existing variants operate in the output space—they refine answer selection but leave the noisy input context unchanged. We observe that when multiple reasoning traces independently cite the same support items, those items are likely key evidence for the question. Building on this input-side consensus signal, we propose SVote-2S, a two-stage self-consistency framework for multi-hop question answering. In Stage 1, SVote-2S performs confidence-weighted voting over support items cited across N sampled traces and selects a compact evidence set. In Stage 2, the model re-reasons over a filtered context containing only the selected evidence paragraphs (about 15% of the original length on average on our benchmarks), enabling more focused reasoning. The final answer is determined by confidence-weighted fusion of samples from both stages. The fusion serves as a robustness safeguard, while the primary gain comes from evidence voting and re-reasoning. Across three benchmarks (HotpotQA, MuSiQue, 2WikiMultihopQA) and three LLMs, SVote-2S improves over SC by 5.36 EM on average and consistently outperforms the strongest output-side baseline (CISC) across all nine settings, without additional training or external retrieval.
Anthology ID:
2026.findings-emnlp.1741
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
37229–37249
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1741/
DOI:
10.18653/2026.findings-emnlp.1741
Bibkey:
Cite (ACL):
Guo Ouyang, Ge Wang, Tao Zhu, Yi Zou, Xuehao Yin, Guoliang Li, and Fuchuan Ni. 2026. SVote-2S: Input-Side Evidence Voting for Two-Stage Self-Consistency in Multi-Hop QA. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 37229–37249, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
SVote-2S: Input-Side Evidence Voting for Two-Stage Self-Consistency in Multi-Hop QA (Ouyang et al., Findings 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.findings-emnlp.1741.pdf