Testing conditional independence under isotonicity

Fuente: arXiv
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Autores principales: Hore, Rohan, Soloff, Jake A., Barber, Rina Foygel, Samworth, Richard J.
Formato: Preprint
Publicado: 2025
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author Hore, Rohan
Soloff, Jake A.
Barber, Rina Foygel
Samworth, Richard J.
author_facet Hore, Rohan
Soloff, Jake A.
Barber, Rina Foygel
Samworth, Richard J.
contents We propose a test of the conditional independence of random variables $X$ and~$Y$ given~$Z$ under the additional assumption that $X$ is stochastically nondecreasing in~$Z$. The well-documented hardness of testing conditional independence means that some further restriction on the null hypothesis parameter space is required. In contrast to existing approaches based on parametric models, smoothness assumptions, or approximations to the conditional distribution of $X$ given $Z$ and/or $Y$ given $Z$, our test requires only the stochastic monotonicity assumption. Our procedure, called \textnormal{\texttt{PairSwap-ICI}}, determines the significance of a statistic by randomly swapping the $X$ values within ordered pairs of~$Z$ values. The matched pairs and the test statistic may depend on both $Y$ and $Z$, providing the analyst with significant flexibility in constructing a powerful test. Our test offers finite-sample Type~I error control, and provably achieves high power against a large class of alternatives. We validate our theoretical findings through a series of simulations and real data experiments.
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id arxiv_https___arxiv_org_abs_2501_06133
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Testing conditional independence under isotonicity
Hore, Rohan
Soloff, Jake A.
Barber, Rina Foygel
Samworth, Richard J.
Methodology
Statistics Theory
We propose a test of the conditional independence of random variables $X$ and~$Y$ given~$Z$ under the additional assumption that $X$ is stochastically nondecreasing in~$Z$. The well-documented hardness of testing conditional independence means that some further restriction on the null hypothesis parameter space is required. In contrast to existing approaches based on parametric models, smoothness assumptions, or approximations to the conditional distribution of $X$ given $Z$ and/or $Y$ given $Z$, our test requires only the stochastic monotonicity assumption. Our procedure, called \textnormal{\texttt{PairSwap-ICI}}, determines the significance of a statistic by randomly swapping the $X$ values within ordered pairs of~$Z$ values. The matched pairs and the test statistic may depend on both $Y$ and $Z$, providing the analyst with significant flexibility in constructing a powerful test. Our test offers finite-sample Type~I error control, and provably achieves high power against a large class of alternatives. We validate our theoretical findings through a series of simulations and real data experiments.
title Testing conditional independence under isotonicity
topic Methodology
Statistics Theory
url https://arxiv.org/abs/2501.06133