Multivariate Standardized Residuals for Conformal Prediction

Fuente: arXiv
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Main Authors: Braun, Sacha, Berta, Eugène, Jordan, Michael I., Bach, Francis
Format: Preprint
Published: 2025
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author Braun, Sacha
Berta, Eugène
Jordan, Michael I.
Bach, Francis
author_facet Braun, Sacha
Berta, Eugène
Jordan, Michael I.
Bach, Francis
contents While split conformal prediction guarantees marginal coverage, approaching the stronger property of conditional coverage is essential for reliable uncertainty quantification. Naive conformal scores, however, suffer from poor conditional coverage in heteroskedastic settings. In univariate regression, this is commonly addressed by normalizing non-conformity scores using an estimated local score variance. In this work, we propose a natural extension of this normalization to the multivariate setting, effectively whitening the residuals to decouple output correlations and standardize local variance. Furthermore, we derive a sufficient condition characterizing a broad class of distributions for which standardized residuals yield asymptotic conditional coverage. We demonstrate that using the Mahalanobis distance induced by a learned local covariance as a non-conformity score provides a closed-form, computationally efficient mechanism for capturing inter-output correlations and heteroskedasticity, avoiding the expensive sampling required by previous methods based on cumulative distribution functions. This structure unlocks several practical extensions, including the handling of missing output values, the refinement of conformal sets when partial information is revealed, and the construction of valid conformal sets for transformations of the output. Finally, we provide extensive empirical evidence on both synthetic and real-world datasets showing that our approach yields conformal sets that improve upon the conditional coverage of existing multivariate baselines.
format Preprint
id arxiv_https___arxiv_org_abs_2507_20941
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Multivariate Standardized Residuals for Conformal Prediction
Braun, Sacha
Berta, Eugène
Jordan, Michael I.
Bach, Francis
Machine Learning
Artificial Intelligence
Methodology
Other Statistics
While split conformal prediction guarantees marginal coverage, approaching the stronger property of conditional coverage is essential for reliable uncertainty quantification. Naive conformal scores, however, suffer from poor conditional coverage in heteroskedastic settings. In univariate regression, this is commonly addressed by normalizing non-conformity scores using an estimated local score variance. In this work, we propose a natural extension of this normalization to the multivariate setting, effectively whitening the residuals to decouple output correlations and standardize local variance. Furthermore, we derive a sufficient condition characterizing a broad class of distributions for which standardized residuals yield asymptotic conditional coverage. We demonstrate that using the Mahalanobis distance induced by a learned local covariance as a non-conformity score provides a closed-form, computationally efficient mechanism for capturing inter-output correlations and heteroskedasticity, avoiding the expensive sampling required by previous methods based on cumulative distribution functions. This structure unlocks several practical extensions, including the handling of missing output values, the refinement of conformal sets when partial information is revealed, and the construction of valid conformal sets for transformations of the output. Finally, we provide extensive empirical evidence on both synthetic and real-world datasets showing that our approach yields conformal sets that improve upon the conditional coverage of existing multivariate baselines.
title Multivariate Standardized Residuals for Conformal Prediction
topic Machine Learning
Artificial Intelligence
Methodology
Other Statistics
url https://arxiv.org/abs/2507.20941