Structured Matrix Scaling for Multi-Class Calibration

Fuente: arXiv
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Autori principali: Berta, Eugène, Holzmüller, David, Jordan, Michael I., Bach, Francis
Natura: Preprint
Pubblicazione: 2025
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author Berta, Eugène
Holzmüller, David
Jordan, Michael I.
Bach, Francis
author_facet Berta, Eugène
Holzmüller, David
Jordan, Michael I.
Bach, Francis
contents Post-hoc recalibration methods are widely used to ensure that classifiers provide faithful probability estimates. We argue that parametric recalibration functions based on logistic regression can be motivated from a simple theoretical setting for both binary and multiclass classification. This insight motivates the use of more expressive calibration methods beyond standard temperature scaling. For multi-class calibration however, a key challenge lies in the increasing number of parameters introduced by more complex models, often coupled with limited calibration data, which can lead to overfitting. Through extensive experiments, we demonstrate that the resulting bias-variance tradeoff can be effectively managed by structured regularization, robust preprocessing and efficient optimization. The resulting methods lead to substantial gains over existing logistic-based calibration techniques. We provide efficient and easy-to-use open-source implementations of our methods, making them an attractive alternative to common temperature, vector, and matrix scaling implementations.
format Preprint
id arxiv_https___arxiv_org_abs_2511_03685
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Structured Matrix Scaling for Multi-Class Calibration
Berta, Eugène
Holzmüller, David
Jordan, Michael I.
Bach, Francis
Machine Learning
Artificial Intelligence
Post-hoc recalibration methods are widely used to ensure that classifiers provide faithful probability estimates. We argue that parametric recalibration functions based on logistic regression can be motivated from a simple theoretical setting for both binary and multiclass classification. This insight motivates the use of more expressive calibration methods beyond standard temperature scaling. For multi-class calibration however, a key challenge lies in the increasing number of parameters introduced by more complex models, often coupled with limited calibration data, which can lead to overfitting. Through extensive experiments, we demonstrate that the resulting bias-variance tradeoff can be effectively managed by structured regularization, robust preprocessing and efficient optimization. The resulting methods lead to substantial gains over existing logistic-based calibration techniques. We provide efficient and easy-to-use open-source implementations of our methods, making them an attractive alternative to common temperature, vector, and matrix scaling implementations.
title Structured Matrix Scaling for Multi-Class Calibration
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2511.03685