Causal Inference on Process Graphs, Part II: Causal Structure and Effect Identification

Fuente: arXiv
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Autori principali: Reiter, Nicolas-Domenic, Wahl, Jonas, Gerhardus, Andreas, Runge, Jakob
Natura: Preprint
Pubblicazione: 2024
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author Reiter, Nicolas-Domenic
Wahl, Jonas
Gerhardus, Andreas
Runge, Jakob
author_facet Reiter, Nicolas-Domenic
Wahl, Jonas
Gerhardus, Andreas
Runge, Jakob
contents A structural vector autoregressive (SVAR) process is a linear causal model for variables that evolve over a discrete set of time points and between which there may be lagged and instantaneous effects. The qualitative causal structure of an SVAR process can be represented by its finite and directed process graph, in which a directed link connects two processes whenever there is a lagged or instantaneous effect between them. At the process graph level, the causal structure of SVAR processes is compactly parameterised in the frequency domain. In this paper, we consider the problem of causal discovery and causal effect estimation from the spectral density, the frequency domain analogue of the auto covariance, of the SVAR process. Causal discovery concerns the recovery of the process graph and causal effect estimation concerns the identification and estimation of causal effects in the frequency domain. We show that information about the process graph, in terms of $d$- and $t$-separation statements, can be identified by verifying algebraic constraints on the spectral density. Furthermore, we introduce a notion of rational identifiability for frequency causal effects that may be confounded by exogenous latent processes, and show that the recent graphical latent factor half-trek criterion can be used on the process graph to assess whether a given (confounded) effect can be identified by rational operations on the entries of the spectral density.
format Preprint
id arxiv_https___arxiv_org_abs_2406_17422
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Causal Inference on Process Graphs, Part II: Causal Structure and Effect Identification
Reiter, Nicolas-Domenic
Wahl, Jonas
Gerhardus, Andreas
Runge, Jakob
Statistics Theory
Methodology
A structural vector autoregressive (SVAR) process is a linear causal model for variables that evolve over a discrete set of time points and between which there may be lagged and instantaneous effects. The qualitative causal structure of an SVAR process can be represented by its finite and directed process graph, in which a directed link connects two processes whenever there is a lagged or instantaneous effect between them. At the process graph level, the causal structure of SVAR processes is compactly parameterised in the frequency domain. In this paper, we consider the problem of causal discovery and causal effect estimation from the spectral density, the frequency domain analogue of the auto covariance, of the SVAR process. Causal discovery concerns the recovery of the process graph and causal effect estimation concerns the identification and estimation of causal effects in the frequency domain. We show that information about the process graph, in terms of $d$- and $t$-separation statements, can be identified by verifying algebraic constraints on the spectral density. Furthermore, we introduce a notion of rational identifiability for frequency causal effects that may be confounded by exogenous latent processes, and show that the recent graphical latent factor half-trek criterion can be used on the process graph to assess whether a given (confounded) effect can be identified by rational operations on the entries of the spectral density.
title Causal Inference on Process Graphs, Part II: Causal Structure and Effect Identification
topic Statistics Theory
Methodology
url https://arxiv.org/abs/2406.17422