Target-Aware Calibration Data Selection for Preserving Uncertainty in Quantized Language Models

Zhen Yang, Sizai Hou, Kaiwen Zheng, Yaofang Liu, Liang He, Yixuan Chen, Kangning Cui


Abstract
Quantization is widely used to deploy large language models, but its effect on uncertainty behavior, such as confidence, margins, and abstention, is rarely treated as a primary objective. We frame calibration-data selection for quantization as a *target-dependent uncertainty-preservation problem*. Different deployments emphasize different regions of the input distribution, yet prior work mainly optimizes accuracy-oriented compression metrics or adjusts scores after quantization. We formalize this goal with distributional and boundary preservation risks, and provide a simple mixture-mismatch argument explaining why no single calibration recipe should be expected to fit all targets. We introduce Doubt-Preserving Quantization (DPQ), a lightweight pre-quantization recipe family that uses full-precision predictions to construct target-aligned calibration mixtures of high-doubt examples and generic anchors. Across 8 language models, 9 NLP benchmarks, and 22 comparison methods, the leading recipe changes with the preservation target: DPQ-r75 leads on SQuAD2 answerability-boundary preservation, while broad multiple-choice QA favors a different set of milder or single-signal recipes, with confidence-only leading and variants such as entropy-only and DPQ-r50 outperforming the boundary-heavy DPQ-r75. These results show that calibration data should be selected for the specific full-precision score behavior a deployment needs to preserve, rather than treated as a fixed quantization detail. Code is available at https://github.com/xi-xiaoran/DPQ.
Anthology ID:
2026.findings-emnlp.670
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
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SIGDAT
Publisher:
Association for Computational Linguistics
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Pages:
14073–14093
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URL:
https://aclanthology.org/2026.findings-emnlp.670/
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Cite (ACL):
Zhen Yang, Sizai Hou, Kaiwen Zheng, Yaofang Liu, Liang He, Yixuan Chen, and Kangning Cui. 2026. Target-Aware Calibration Data Selection for Preserving Uncertainty in Quantized Language Models. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 14073–14093, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Target-Aware Calibration Data Selection for Preserving Uncertainty in Quantized Language Models (Yang et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.670.pdf