Parameter identification in linear non-Gaussian causal models under general confounding

Fuente: arXiv
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Autori principali: Tramontano, Daniele, Drton, Mathias, Etesami, Jalal
Natura: Preprint
Pubblicazione: 2024
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author Tramontano, Daniele
Drton, Mathias
Etesami, Jalal
author_facet Tramontano, Daniele
Drton, Mathias
Etesami, Jalal
contents Linear non-Gaussian causal models postulate that each random variable is a linear function of parent variables and non-Gaussian exogenous error terms. We study identification of the linear coefficients when such models contain latent variables. Our focus is on the commonly studied acyclic setting, where each model corresponds to a directed acyclic graph (DAG). For this case, prior literature has demonstrated that connections to overcomplete independent component analysis yield effective criteria to decide parameter identifiability in latent variable models. However, this connection is based on the assumption that the observed variables linearly depend on the latent variables. Departing from this assumption, we treat models that allow for arbitrary non-linear latent confounding. Our main result is a graphical criterion that is necessary and sufficient for deciding the generic identifiability of direct causal effects. Moreover, we provide an algorithmic implementation of the criterion with a run time that is polynomial in the number of observed variables. Finally, we report on estimation heuristics based on the identification result and explore a generalization to models with feedback loops.
format Preprint
id arxiv_https___arxiv_org_abs_2405_20856
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Parameter identification in linear non-Gaussian causal models under general confounding
Tramontano, Daniele
Drton, Mathias
Etesami, Jalal
Methodology
Machine Learning
Linear non-Gaussian causal models postulate that each random variable is a linear function of parent variables and non-Gaussian exogenous error terms. We study identification of the linear coefficients when such models contain latent variables. Our focus is on the commonly studied acyclic setting, where each model corresponds to a directed acyclic graph (DAG). For this case, prior literature has demonstrated that connections to overcomplete independent component analysis yield effective criteria to decide parameter identifiability in latent variable models. However, this connection is based on the assumption that the observed variables linearly depend on the latent variables. Departing from this assumption, we treat models that allow for arbitrary non-linear latent confounding. Our main result is a graphical criterion that is necessary and sufficient for deciding the generic identifiability of direct causal effects. Moreover, we provide an algorithmic implementation of the criterion with a run time that is polynomial in the number of observed variables. Finally, we report on estimation heuristics based on the identification result and explore a generalization to models with feedback loops.
title Parameter identification in linear non-Gaussian causal models under general confounding
topic Methodology
Machine Learning
url https://arxiv.org/abs/2405.20856