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Main Authors: Zeng, Jiapeng, Prabhu, Yogesh, Zeng, Zhanpeng, Newton, Michael A., Singh, Vikas
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2605.23189
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author Zeng, Jiapeng
Prabhu, Yogesh
Zeng, Zhanpeng
Newton, Michael A.
Singh, Vikas
author_facet Zeng, Jiapeng
Prabhu, Yogesh
Zeng, Zhanpeng
Newton, Michael A.
Singh, Vikas
contents Conformal prediction (CP) gives distribution-free coverage for modern vision and language models, but it is often forced to make a ranking decision from a single unstable nonconformity score. Standard CP uses one realization, while average-then-calibrate variants smooth multiple realizations into a point estimate. Both options discard the inconsistency that can help identify whether a candidate is indeed stable. A weak answer can enter the conformal set even if the evidence is not strong, simply because one posterior sample or prompt phrasing made it look strong. But variability can help distinguish a stable signal from noise-driven fluctuations. We describe an empirical Bayes conformal prediction framework that uses $r$-values to convert score variability into an uncertainty informed nonconformity score. The resulting $r$-value estimates how likely a candidate's latent score belongs to the top-ranked group after accounting for both its mean score and its uncertainty. It admits both a closed-form Normal-Normal empirical Bayes estimator and a nonparametric posterior-sampling estimator. Using the $r$-value as the nonconformity score preserves the target conformal coverage while provably reducing the inclusion of high variance false candidates under mild regularity conditions. Across image classification, CLIP-based VLM benchmarks, and LLMs, we show that $r$-value conformal prediction preserves target coverage while improving ranking stability and reducing set size when variability is informative, and reverting to CP-like behavior when variability vanishes.
format Preprint
id arxiv_https___arxiv_org_abs_2605_23189
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Empirical Bayes Conformal Prediction for Vision and Language Models
Zeng, Jiapeng
Prabhu, Yogesh
Zeng, Zhanpeng
Newton, Michael A.
Singh, Vikas
Machine Learning
Conformal prediction (CP) gives distribution-free coverage for modern vision and language models, but it is often forced to make a ranking decision from a single unstable nonconformity score. Standard CP uses one realization, while average-then-calibrate variants smooth multiple realizations into a point estimate. Both options discard the inconsistency that can help identify whether a candidate is indeed stable. A weak answer can enter the conformal set even if the evidence is not strong, simply because one posterior sample or prompt phrasing made it look strong. But variability can help distinguish a stable signal from noise-driven fluctuations. We describe an empirical Bayes conformal prediction framework that uses $r$-values to convert score variability into an uncertainty informed nonconformity score. The resulting $r$-value estimates how likely a candidate's latent score belongs to the top-ranked group after accounting for both its mean score and its uncertainty. It admits both a closed-form Normal-Normal empirical Bayes estimator and a nonparametric posterior-sampling estimator. Using the $r$-value as the nonconformity score preserves the target conformal coverage while provably reducing the inclusion of high variance false candidates under mild regularity conditions. Across image classification, CLIP-based VLM benchmarks, and LLMs, we show that $r$-value conformal prediction preserves target coverage while improving ranking stability and reducing set size when variability is informative, and reverting to CP-like behavior when variability vanishes.
title Empirical Bayes Conformal Prediction for Vision and Language Models
topic Machine Learning
url https://arxiv.org/abs/2605.23189