Optimal Adjustment Sets for Nonparametric Estimation of Weighted Controlled Direct Effect

Fuente: arXiv
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Main Authors: Lin, Ruiyang, Guo, Yongyi, Gan, Kyra
Format: Preprint
Published: 2025
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author Lin, Ruiyang
Guo, Yongyi
Gan, Kyra
author_facet Lin, Ruiyang
Guo, Yongyi
Gan, Kyra
contents The weighted controlled direct effect (WCDE) generalizes the standard controlled direct effect (CDE) by averaging over the mediator distribution, providing a robust estimate when treatment effects vary across mediator levels. This makes the WCDE especially relevant in fairness analysis, where it isolates the direct effect of an exposure on an outcome, independent of mediating pathways. This work establishes three fundamental advances for WCDE in observational studies: First, we establish necessary and sufficient conditions for the unique identifiability of the WCDE, clarifying when it diverges from the CDE. Next, we consider nonparametric estimation of the WCDE and derive its influence function, focusing on the class of regular and asymptotically linear estimators. Lastly, we characterize the optimal covariate adjustment set that minimizes the asymptotic variance, demonstrating how mediator-confounder interactions introduce distinct requirements compared to average treatment effect estimation. Our results offer a principled framework for efficient estimation of direct effects in complex causal systems, with practical applications in fairness and mediation analysis.
format Preprint
id arxiv_https___arxiv_org_abs_2506_09871
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Optimal Adjustment Sets for Nonparametric Estimation of Weighted Controlled Direct Effect
Lin, Ruiyang
Guo, Yongyi
Gan, Kyra
Methodology
Statistics Theory
The weighted controlled direct effect (WCDE) generalizes the standard controlled direct effect (CDE) by averaging over the mediator distribution, providing a robust estimate when treatment effects vary across mediator levels. This makes the WCDE especially relevant in fairness analysis, where it isolates the direct effect of an exposure on an outcome, independent of mediating pathways. This work establishes three fundamental advances for WCDE in observational studies: First, we establish necessary and sufficient conditions for the unique identifiability of the WCDE, clarifying when it diverges from the CDE. Next, we consider nonparametric estimation of the WCDE and derive its influence function, focusing on the class of regular and asymptotically linear estimators. Lastly, we characterize the optimal covariate adjustment set that minimizes the asymptotic variance, demonstrating how mediator-confounder interactions introduce distinct requirements compared to average treatment effect estimation. Our results offer a principled framework for efficient estimation of direct effects in complex causal systems, with practical applications in fairness and mediation analysis.
title Optimal Adjustment Sets for Nonparametric Estimation of Weighted Controlled Direct Effect
topic Methodology
Statistics Theory
url https://arxiv.org/abs/2506.09871