Uncertainty-Aware Answer Selection for Improved Reasoning in Multi-LLM Systems

Aakriti Agrawal, Rohith Aralikatti, Anirudh Satheesh, Souradip Chakraborty, Amrit Singh Bedi, Furong Huang


Abstract
Large Language Models (LLMs) have demonstrated exceptional capabilities, yet selecting the most reliable response from multiple LLMs remains a challenge, particularly in resource-constrained settings. Existing approaches often depend on costly external verifiers, human evaluators, or self-consistency techniques that require multiple samples from a single model. While multi-LLM systems produce more diverse responses than single models and thus have greater potential, they often underperform compared to single LLM self-consistency. In this work, we propose a calibrated log-likelihood-based selection framework to improve multi-LLM performance. Our approach leverages uncertainty estimation to identify the most confident response while minimizing inference costs. We show that our method outperforms majority voting and exceeds self-consistency performance when using a large number of model calls. Through extensive experiments, we demonstrate improvements of approx. 4%, 3%, and 5% on GSM8K, MMLU, and ARC, respectively, when applying uncertainty-aware selection to multi-LLM systems.
Anthology ID:
2025.findings-emnlp.1367
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2025
Month:
November
Year:
2025
Address:
Suzhou, China
Editors:
Christos Christodoulopoulos, Tanmoy Chakraborty, Carolyn Rose, Violet Peng
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
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Pages:
25090–25098
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URL:
https://aclanthology.org/2025.findings-emnlp.1367/
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Cite (ACL):
Aakriti Agrawal, Rohith Aralikatti, Anirudh Satheesh, Souradip Chakraborty, Amrit Singh Bedi, and Furong Huang. 2025. Uncertainty-Aware Answer Selection for Improved Reasoning in Multi-LLM Systems. In Findings of the Association for Computational Linguistics: EMNLP 2025, pages 25090–25098, Suzhou, China. Association for Computational Linguistics.
Cite (Informal):
Uncertainty-Aware Answer Selection for Improved Reasoning in Multi-LLM Systems (Agrawal et al., Findings 2025)
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https://aclanthology.org/2025.findings-emnlp.1367.pdf
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