PLAUSIEVE:A Distribution Based Framework for Measuring Model Belief Beyond Logits

Arghodeep Nandi, Tanmoy Chakraborty


Abstract
Prompting has transformed large language models into general-purpose decision systems, where token-level probabilities are often treated as indicators of model preference and correctness. However, directly interpreting these probabilities is challenging due to calibration disparities, tokenizer variability, and inconsistent output distributions across models, limiting their statistical comparability. This raises a fundamental question: *when can a model be said to be confident in its decision or preference?* Addressing this question remains an open and important area of research. We introduce **PLAUSIEVE**, a novel distribution-based statistical framework that estimates model preference through a forward pass without token generation. **PLAUSIEVE** provides a calibration-robust and model-independent mechanism for quantifying preference without relying on fixed thresholds or individual tokens. We apply **PLAUSIEVE** in estimating model belief, across two prompt settings (direct and epistemic), two confidence levels, and five models from four families to study prompt–architecture interactions. Our analysis shows significant improvements under epistemic prompting, with nearly 100% gains in certain model combinations. Notably, **Llama-3.2-3B** outperforms the larger **Gemma-7B** under epistemic prompting in terms of both decisiveness and veracity, demonstrating that model architecture plays a more significant role than scale in shaping belief formation.
Anthology ID:
2026.findings-aacl.17
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
Note:
Pages:
300–328
Language:
URL:
https://aclanthology.org/2026.findings-aacl.17/
DOI:
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Cite (ACL):
Arghodeep Nandi and Tanmoy Chakraborty. 2026. PLAUSIEVE:A Distribution Based Framework for Measuring Model Belief Beyond Logits. In Findings of the Association for Computational Linguistics: IJCNLP-AACL 2026, pages 300–328, Hengqin, China. Association for Computational Linguistics.
Cite (Informal):
PLAUSIEVE:A Distribution Based Framework for Measuring Model Belief Beyond Logits (Nandi & Chakraborty, Findings 2026)
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https://aclanthology.org/2026.findings-aacl.17.pdf