CALIBER: Calibrating Confidence Before and After Reasoning in Language Models

Conor Finlay, Joshua Kurien, Saurabh Dash, Marzieh Fadaee, Beyza Ermis


Abstract
Reasoning language models are increasingly asked not only to answer difficult questions, but also to estimate their likelihood of success. Existing methods typically elicit confidence only once: either before thinking or after answering. We argue that confidence in reasoning models is state-dependent: before thinking, confidence should estimate whether the current policy will solve the prompt, while after thinking it should predict whether the realized answer is correct. This distinction determines the appropriate supervision target: prompt-level success should supervise confidence estimates made after seeing the prompt, while individual answer-level correctness should supervise confidence estimates made after answering. We introduce CALIBER (Calibration Before and After Reasoning), which elicits both estimates and supervises each with the target matched to its information state. Under this unified protocol, CALIBER reduces Expected Calibration Error (ECE) by 52.5% over the strongest single-confidence baseline on BigMathDigits for a 7B model, while achieving the best Brier score and AUROC, and remains within 2.0 points of the best accuracy. Out of distribution at this scale, it achieves the best ECE and Brier score on all three benchmarks, and ties for the best AUROC on SimpleQA. On a larger 30B model, CALIBER obtains the best ECE and Brier score on all four benchmarks and the best AUROC on three of the four. Ablations further show that this position–target alignment is most beneficial under distribution shift.
Anthology ID:
2026.findings-emnlp.2420
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:
51966–51980
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.2420/
DOI:
Bibkey:
Cite (ACL):
Conor Finlay, Joshua Kurien, Saurabh Dash, Marzieh Fadaee, and Beyza Ermis. 2026. CALIBER: Calibrating Confidence Before and After Reasoning in Language Models. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 51966–51980, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
CALIBER: Calibrating Confidence Before and After Reasoning in Language Models (Finlay et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.2420.pdf