Cellwise Robust Discriminant Analysis

Fuente: arXiv
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Main Authors: Centofanti, Fabio, Dagidir, Can Hakan, Hubert, Mia, Rousseeuw, Peter J.
Format: Preprint
Published: 2026
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author Centofanti, Fabio
Dagidir, Can Hakan
Hubert, Mia
Rousseeuw, Peter J.
author_facet Centofanti, Fabio
Dagidir, Can Hakan
Hubert, Mia
Rousseeuw, Peter J.
contents Classical discriminant analysis (DA) is based on the mean and empirical covariance matrix of each class, both of which are sensitive to outliers in the data. In the past the focus was on casewise outliers, that is, datapoints that lie far away. But nowadays there is increasing interest in cellwise outliers, that are unexpected entries in the data matrix. Removing an entire case because it has one or a few outlying cells would lose much information. Cellwise robust methods aim to detect the outlying cells and to preserve the information in the other cells. We propose a DA method that is trained by estimating the location and covariance of each class by cellwise and casewise robust estimators, that can also handle NA's. The main novelty of our approach is in the prediction on test data, that may contain outlying cells and NA's themselves. The new robust discriminant function is derived from a novel statistical model by penalized maximum likelihood. We focus on quadratic DA, but also cover the setting of linear DA. The new cellQDA and cellLDA methods perform well in simulation. The approach is illustrated on real data, and the results are interpreted with the help of graphical displays.
format Preprint
id arxiv_https___arxiv_org_abs_2605_30178
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Cellwise Robust Discriminant Analysis
Centofanti, Fabio
Dagidir, Can Hakan
Hubert, Mia
Rousseeuw, Peter J.
Methodology
Computation
Classical discriminant analysis (DA) is based on the mean and empirical covariance matrix of each class, both of which are sensitive to outliers in the data. In the past the focus was on casewise outliers, that is, datapoints that lie far away. But nowadays there is increasing interest in cellwise outliers, that are unexpected entries in the data matrix. Removing an entire case because it has one or a few outlying cells would lose much information. Cellwise robust methods aim to detect the outlying cells and to preserve the information in the other cells. We propose a DA method that is trained by estimating the location and covariance of each class by cellwise and casewise robust estimators, that can also handle NA's. The main novelty of our approach is in the prediction on test data, that may contain outlying cells and NA's themselves. The new robust discriminant function is derived from a novel statistical model by penalized maximum likelihood. We focus on quadratic DA, but also cover the setting of linear DA. The new cellQDA and cellLDA methods perform well in simulation. The approach is illustrated on real data, and the results are interpreted with the help of graphical displays.
title Cellwise Robust Discriminant Analysis
topic Methodology
Computation
url https://arxiv.org/abs/2605.30178