Building a stable classifier with the inflated argmax

Fuente: arXiv
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Main Authors: Soloff, Jake A., Barber, Rina Foygel, Willett, Rebecca
Format: Preprint
Published: 2024
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author Soloff, Jake A.
Barber, Rina Foygel
Willett, Rebecca
author_facet Soloff, Jake A.
Barber, Rina Foygel
Willett, Rebecca
contents We propose a new framework for algorithmic stability in the context of multiclass classification. In practice, classification algorithms often operate by first assigning a continuous score (for instance, an estimated probability) to each possible label, then taking the maximizer -- i.e., selecting the class that has the highest score. A drawback of this type of approach is that it is inherently unstable, meaning that it is very sensitive to slight perturbations of the training data, since taking the maximizer is discontinuous. Motivated by this challenge, we propose a pipeline for constructing stable classifiers from data, using bagging (i.e., resampling and averaging) to produce stable continuous scores, and then using a stable relaxation of argmax, which we call the "inflated argmax," to convert these scores to a set of candidate labels. The resulting stability guarantee places no distributional assumptions on the data, does not depend on the number of classes or dimensionality of the covariates, and holds for any base classifier. Using a common benchmark data set, we demonstrate that the inflated argmax provides necessary protection against unstable classifiers, without loss of accuracy.
format Preprint
id arxiv_https___arxiv_org_abs_2405_14064
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Building a stable classifier with the inflated argmax
Soloff, Jake A.
Barber, Rina Foygel
Willett, Rebecca
Machine Learning
Statistics Theory
We propose a new framework for algorithmic stability in the context of multiclass classification. In practice, classification algorithms often operate by first assigning a continuous score (for instance, an estimated probability) to each possible label, then taking the maximizer -- i.e., selecting the class that has the highest score. A drawback of this type of approach is that it is inherently unstable, meaning that it is very sensitive to slight perturbations of the training data, since taking the maximizer is discontinuous. Motivated by this challenge, we propose a pipeline for constructing stable classifiers from data, using bagging (i.e., resampling and averaging) to produce stable continuous scores, and then using a stable relaxation of argmax, which we call the "inflated argmax," to convert these scores to a set of candidate labels. The resulting stability guarantee places no distributional assumptions on the data, does not depend on the number of classes or dimensionality of the covariates, and holds for any base classifier. Using a common benchmark data set, we demonstrate that the inflated argmax provides necessary protection against unstable classifiers, without loss of accuracy.
title Building a stable classifier with the inflated argmax
topic Machine Learning
Statistics Theory
url https://arxiv.org/abs/2405.14064