Causal Discovery with Mixed Latent Confounding via Precision Decomposition
Amir Asiaee, Samhita Pal, James O'quinn, James P. Long
TL;DR
This work tackles causal discovery in linear Gaussian SEMs under mixed latent confounding, consisting of pervasive low-rank and sparse localized confounders. It introduces DCL-DECOR, a three-stage pipeline that (i) decomposes the observed precision into a structured component and a low-rank part, (ii) inverts the structured component to form a pervasive-adjusted covariance, and (iii) applies a correlated-noise DAG learner (DECOR-GL) with bow-free reconciliation to recover a minimal bow-free ADMG. The paper provides identifiability and stability guarantees for the precision decomposition and the conditional covariance, and it shows that the end-to-end approach consistently recovers a representative bow-free causal target under mild assumptions. Synthetic experiments demonstrate robust improvements in directed-edge recovery over applying standard DAG learners directly to confounded data, particularly as pervasive confounding strengthens or local confounding increases. Overall, the work offers a modular, principled path to causal discovery in the Gaussian, linear setting with mixed latent confounding, combining precision-domain deconfounding with state-of-the-art DAG learning.
Abstract
We study causal discovery from observational data in linear Gaussian systems affected by \emph{mixed latent confounding}, where some unobserved factors act broadly across many variables while others influence only small subsets. This setting is common in practice and poses a challenge for existing methods: differentiable and score-based DAG learners can misinterpret global latent effects as causal edges, while latent-variable graphical models recover only undirected structure. We propose \textsc{DCL-DECOR}, a modular, precision-led pipeline that separates these roles. The method first isolates pervasive latent effects by decomposing the observed precision matrix into a structured component and a low-rank component. The structured component corresponds to the conditional distribution after accounting for pervasive confounders and retains only local dependence induced by the causal graph and localized confounding. A correlated-noise DAG learner is then applied to this deconfounded representation to recover directed edges while modeling remaining structured error correlations, followed by a simple reconciliation step to enforce bow-freeness. We provide identifiability results that characterize the recoverable causal target under mixed confounding and show how the overall problem reduces to well-studied subproblems with modular guarantees. Synthetic experiments that vary the strength and dimensionality of pervasive confounding demonstrate consistent improvements in directed edge recovery over applying correlated-noise DAG learning directly to the confounded data.
