On the Parameter Identifiability of Partially Observed Linear Causal Models

Fuente: arXiv
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Hauptverfasser: Dong, Xinshuai, Ng, Ignavier, Huang, Biwei, Sun, Yuewen, Jin, Songyao, Legaspi, Roberto, Spirtes, Peter, Zhang, Kun
Format: Preprint
Veröffentlicht: 2024
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author Dong, Xinshuai
Ng, Ignavier
Huang, Biwei
Sun, Yuewen
Jin, Songyao
Legaspi, Roberto
Spirtes, Peter
Zhang, Kun
author_facet Dong, Xinshuai
Ng, Ignavier
Huang, Biwei
Sun, Yuewen
Jin, Songyao
Legaspi, Roberto
Spirtes, Peter
Zhang, Kun
contents Linear causal models are important tools for modeling causal dependencies and yet in practice, only a subset of the variables can be observed. In this paper, we examine the parameter identifiability of these models by investigating whether the edge coefficients can be recovered given the causal structure and partially observed data. Our setting is more general than that of prior research - we allow all variables, including both observed and latent ones, to be flexibly related, and we consider the coefficients of all edges, whereas most existing works focus only on the edges between observed variables. Theoretically, we identify three types of indeterminacy for the parameters in partially observed linear causal models. We then provide graphical conditions that are sufficient for all parameters to be identifiable and show that some of them are provably necessary. Methodologically, we propose a novel likelihood-based parameter estimation method that addresses the variance indeterminacy of latent variables in a specific way and can asymptotically recover the underlying parameters up to trivial indeterminacy. Empirical studies on both synthetic and real-world datasets validate our identifiability theory and the effectiveness of the proposed method in the finite-sample regime. Code: https://github.com/dongxinshuai/scm-identify.
format Preprint
id arxiv_https___arxiv_org_abs_2407_16975
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On the Parameter Identifiability of Partially Observed Linear Causal Models
Dong, Xinshuai
Ng, Ignavier
Huang, Biwei
Sun, Yuewen
Jin, Songyao
Legaspi, Roberto
Spirtes, Peter
Zhang, Kun
Machine Learning
Methodology
Linear causal models are important tools for modeling causal dependencies and yet in practice, only a subset of the variables can be observed. In this paper, we examine the parameter identifiability of these models by investigating whether the edge coefficients can be recovered given the causal structure and partially observed data. Our setting is more general than that of prior research - we allow all variables, including both observed and latent ones, to be flexibly related, and we consider the coefficients of all edges, whereas most existing works focus only on the edges between observed variables. Theoretically, we identify three types of indeterminacy for the parameters in partially observed linear causal models. We then provide graphical conditions that are sufficient for all parameters to be identifiable and show that some of them are provably necessary. Methodologically, we propose a novel likelihood-based parameter estimation method that addresses the variance indeterminacy of latent variables in a specific way and can asymptotically recover the underlying parameters up to trivial indeterminacy. Empirical studies on both synthetic and real-world datasets validate our identifiability theory and the effectiveness of the proposed method in the finite-sample regime. Code: https://github.com/dongxinshuai/scm-identify.
title On the Parameter Identifiability of Partially Observed Linear Causal Models
topic Machine Learning
Methodology
url https://arxiv.org/abs/2407.16975