Dimension-reduced outcome-weighted learning for estimating individualized treatment regimes in observational studies

Fuente: arXiv
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Main Authors: Son, Sungtaek, Lila, Eardi, Chan, Kwun Chuen Gary
Format: Preprint
Published: 2026
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author Son, Sungtaek
Lila, Eardi
Chan, Kwun Chuen Gary
author_facet Son, Sungtaek
Lila, Eardi
Chan, Kwun Chuen Gary
contents Individualized treatment regimes (ITRs) aim to improve clinical outcomes by assigning treatment based on patient-specific characteristics. However, existing methods often struggle with high-dimensional covariates, limiting accuracy, interpretability, and real-world applicability. We propose a novel sufficient dimension reduction approach that directly targets the contrast between potential outcomes and identifies a low-dimensional subspace of the covariates capturing treatment effect heterogeneity. This reduced representation enables more accurate estimation of optimal ITRs through outcome-weighted learning. To accommodate observational data, our method incorporates kernel-based covariate balancing, allowing treatment assignment to depend on the full covariate set and avoiding the restrictive assumption that the subspace sufficient for modeling heterogeneous treatment effects is also sufficient for confounding adjustment. We show that the proposed method achieves universal consistency, i.e., its risk converges to the Bayes risk, under mild regularity conditions. We demonstrate its finite sample performance through simulations and an analysis of intensive care unit sepsis patient data to determine who should receive transthoracic echocardiography.
format Preprint
id arxiv_https___arxiv_org_abs_2601_06782
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Dimension-reduced outcome-weighted learning for estimating individualized treatment regimes in observational studies
Son, Sungtaek
Lila, Eardi
Chan, Kwun Chuen Gary
Machine Learning
Methodology
Individualized treatment regimes (ITRs) aim to improve clinical outcomes by assigning treatment based on patient-specific characteristics. However, existing methods often struggle with high-dimensional covariates, limiting accuracy, interpretability, and real-world applicability. We propose a novel sufficient dimension reduction approach that directly targets the contrast between potential outcomes and identifies a low-dimensional subspace of the covariates capturing treatment effect heterogeneity. This reduced representation enables more accurate estimation of optimal ITRs through outcome-weighted learning. To accommodate observational data, our method incorporates kernel-based covariate balancing, allowing treatment assignment to depend on the full covariate set and avoiding the restrictive assumption that the subspace sufficient for modeling heterogeneous treatment effects is also sufficient for confounding adjustment. We show that the proposed method achieves universal consistency, i.e., its risk converges to the Bayes risk, under mild regularity conditions. We demonstrate its finite sample performance through simulations and an analysis of intensive care unit sepsis patient data to determine who should receive transthoracic echocardiography.
title Dimension-reduced outcome-weighted learning for estimating individualized treatment regimes in observational studies
topic Machine Learning
Methodology
url https://arxiv.org/abs/2601.06782