Spatial Deconfounder: Interference-Aware Deconfounding for Spatial Causal Inference
Ayush Khot, Miruna Oprescu, Maresa Schröder, Ai Kagawa, Xihaier Luo
TL;DR
The paper tackles causal inference in spatial settings plagued by both interference and unobserved spatial confounding. It introduces the Spatial Deconfounder, a two-stage framework that first reconstructs a substitute latent confounder using a CVAE with a spatial prior from local and neighbor treatments, then uses a flexible outcome model to estimate direct and spillover effects. The authors prove identifiability of these effects under mild assumptions and demonstrate empirically that their method reduces bias relative to spatial baselines on extended SpaCE datasets drawn from environmental health and social science data. This approach reframes interference as a rich signal for uncovering hidden structure, enabling robust causal estimates in structured spatial systems with limited observability. The work bridges spatial causal inference, deconfounding, and deep latent-variable modeling, and outlines avenues for extending to spatiotemporal data and continuous treatments.
Abstract
Causal inference in spatial domains faces two intertwined challenges: (1) unmeasured spatial factors, such as weather, air pollution, or mobility, that confound treatment and outcome, and (2) interference from nearby treatments that violate standard no-interference assumptions. While existing methods typically address one by assuming away the other, we show they are deeply connected: interference reveals structure in the latent confounder. Leveraging this insight, we propose the Spatial Deconfounder, a two-stage method that reconstructs a substitute confounder from local treatment vectors using a conditional variational autoencoder (CVAE) with a spatial prior, then estimates causal effects via a flexible outcome model. We show that this approach enables nonparametric identification of both direct and spillover effects under weak assumptions--without requiring multiple treatment types or a known model of the latent field. Empirically, we extend SpaCE, a benchmark suite for spatial confounding, to include treatment interference, and show that the Spatial Deconfounder consistently improves effect estimation across real-world datasets in environmental health and social science. By turning interference into a multi-cause signal, our framework bridges spatial and deconfounding literatures to advance robust causal inference in structured data.
