Are LLM Decisions Faithful to Verbal Confidence?

Jiawei Wang, Yanfei Zhou, Siddartha Devic, Deqing Fu


Abstract
Large Language Models (LLMs) can produce surprisingly sophisticated estimates of their own uncertainty. However, it remains unclear to what extent this expressed confidence is tied to the reasoning, knowledge, or decision making of the model. To test this, we introduce RiskEval: a framework designed to evaluate whether models adjust their abstention policies in response to varying error penalties. Our evaluation of several frontier models reveals a critical dissociation: models are neither cost-aware when articulating their verbal confidence, nor strategically responsive when deciding whether to engage or abstain under high-penalty conditions. Even when extreme penalties render frequent abstention the mathematically optimal strategy, models almost never abstain, resulting in utility collapse. This indicates that calibrated verbal confidence scores may not be sufficient to create trustworthy and interpretable AI systems, as current models lack the strategic agency to convert uncertainty signals into optimal and risk-sensitive decisions.
Anthology ID:
2026.emnlp-main.759
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
17578–17594
Language:
URL:
https://aclanthology.org/2026.emnlp-main.759/
DOI:
Bibkey:
Cite (ACL):
Jiawei Wang, Yanfei Zhou, Siddartha Devic, and Deqing Fu. 2026. Are LLM Decisions Faithful to Verbal Confidence?. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 17578–17594, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Are LLM Decisions Faithful to Verbal Confidence? (Wang et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.759.pdf