Self-Anchoring Calibration Drift in Large Language Models: How Multi-Turn Conversations Reshape Model Confidence

Harshavardhan


Abstract
Self-Anchoring Calibration Drift (SACD), a tendency for large language models (LLMs) to show systematic changes in expressed confidence when building iteratively on their own prior outputs across multi-turn conversations. Through a controlled three-condition study comparing Claude Sonnet 4.6, Gemini 3.1 Pro, and GPT-5.2 across factual, technical, and open-ended domains, we find that SACD is real but multiform: models exhibit distinct self-anchoring signatures ranging from active confidence suppression to calibration improvement suppression, with effects concentrated in open-ended domains. These findings challenge the adequacy of single-turn calibration evaluation for characterizing LLM reliability in realistic multi-turn deployment contexts. Code and data are available at https://github.com/hvardhan878/calibration-drift
Anthology ID:
2026.gem-main.4
Volume:
Proceedings of the Fifth Workshop on Generation, Evaluation and Metrics (GEM)
Month:
July
Year:
2026
Address:
San Diego, California, USA
Editors:
Simon Mille, Sebastian Gehrmann, Patrícia Schmidtová, Ondřej Dušek, Marzieh Fadaee, Kyle Lo, Enrico Santus, Gabriel Stanovsky
Venues:
GEM | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
34–40
Language:
URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.gem-main.4/
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Bibkey:
Cite (ACL):
Harshavardhan. 2026. Self-Anchoring Calibration Drift in Large Language Models: How Multi-Turn Conversations Reshape Model Confidence. In Proceedings of the Fifth Workshop on Generation, Evaluation and Metrics (GEM), pages 34–40, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
Self-Anchoring Calibration Drift in Large Language Models: How Multi-Turn Conversations Reshape Model Confidence (Harshavardhan, GEM 2026)
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https://preview.aclanthology.org/ingest-acl-workshops/2026.gem-main.4.pdf