On the breakdown point of transport-based quantiles

Fuente: arXiv
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Main Authors: Avella-Medina, Marco, González-Sanz, Alberto
Format: Preprint
Published: 2024
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author Avella-Medina, Marco
González-Sanz, Alberto
author_facet Avella-Medina, Marco
González-Sanz, Alberto
contents Recent work has used optimal transport ideas to generalize the notion of (center-outward) quantiles to dimension $d\geq 2$. We study the robustness properties of these transport-based quantiles by deriving their breakdown point, roughly, the smallest amount of contamination required to make these quantiles take arbitrarily aberrant values. We prove that the transport median defined in Chernozhukov et al.~(2017) and Hallin et al.~(2021) has breakdown point of $1/2$. Moreover, a point in the transport depth contour of order $τ\in [0,1/2]$ has breakdown point of $τ$. This shows that the multivariate transport depth shares the same breakdown properties as its univariate counterpart. Our proof relies on a general argument connecting the breakdown point of transport maps evaluated at a point to the Tukey depth of that point in the reference measure.
format Preprint
id arxiv_https___arxiv_org_abs_2410_16554
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On the breakdown point of transport-based quantiles
Avella-Medina, Marco
González-Sanz, Alberto
Statistics Theory
Methodology
62G35, 62G30
Recent work has used optimal transport ideas to generalize the notion of (center-outward) quantiles to dimension $d\geq 2$. We study the robustness properties of these transport-based quantiles by deriving their breakdown point, roughly, the smallest amount of contamination required to make these quantiles take arbitrarily aberrant values. We prove that the transport median defined in Chernozhukov et al.~(2017) and Hallin et al.~(2021) has breakdown point of $1/2$. Moreover, a point in the transport depth contour of order $τ\in [0,1/2]$ has breakdown point of $τ$. This shows that the multivariate transport depth shares the same breakdown properties as its univariate counterpart. Our proof relies on a general argument connecting the breakdown point of transport maps evaluated at a point to the Tukey depth of that point in the reference measure.
title On the breakdown point of transport-based quantiles
topic Statistics Theory
Methodology
62G35, 62G30
url https://arxiv.org/abs/2410.16554