Doubly Robust Fusion of Many Treatments for Policy Learning

Fuente: arXiv
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Autori principali: Zhu, Ke, Chu, Jianing, Lipkovich, Ilya, Ye, Wenyu, Yang, Shu
Natura: Preprint
Pubblicazione: 2025
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author Zhu, Ke
Chu, Jianing
Lipkovich, Ilya
Ye, Wenyu
Yang, Shu
author_facet Zhu, Ke
Chu, Jianing
Lipkovich, Ilya
Ye, Wenyu
Yang, Shu
contents Individualized treatment rules/recommendations (ITRs) aim to improve patient outcomes by tailoring treatments to the characteristics of each individual. However, when there are many treatment groups, existing methods face significant challenges due to data sparsity within treatment groups and highly unbalanced covariate distributions across groups. To address these challenges, we propose a novel calibration-weighted treatment fusion procedure that robustly balances covariates across treatment groups and fuses similar treatments using a penalized working model. The fusion procedure ensures the recovery of latent treatment group structures when either the calibration model or the outcome model is correctly specified. In the fused treatment space, practitioners can seamlessly apply state-of-the-art ITR learning methods with the flexibility to utilize a subset of covariates, thereby achieving robustness while addressing practical concerns such as fairness. We establish theoretical guarantees, including consistency, the oracle property of treatment fusion, and regret bounds when integrated with multi-armed ITR learning methods such as policy trees. Simulation studies show superior group recovery and policy value compared to existing approaches. We illustrate the practical utility of our method using a nationwide electronic health record-derived de-identified database containing data from patients with Chronic Lymphocytic Leukemia and Small Lymphocytic Lymphoma.
format Preprint
id arxiv_https___arxiv_org_abs_2505_08092
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Doubly Robust Fusion of Many Treatments for Policy Learning
Zhu, Ke
Chu, Jianing
Lipkovich, Ilya
Ye, Wenyu
Yang, Shu
Methodology
Machine Learning
Individualized treatment rules/recommendations (ITRs) aim to improve patient outcomes by tailoring treatments to the characteristics of each individual. However, when there are many treatment groups, existing methods face significant challenges due to data sparsity within treatment groups and highly unbalanced covariate distributions across groups. To address these challenges, we propose a novel calibration-weighted treatment fusion procedure that robustly balances covariates across treatment groups and fuses similar treatments using a penalized working model. The fusion procedure ensures the recovery of latent treatment group structures when either the calibration model or the outcome model is correctly specified. In the fused treatment space, practitioners can seamlessly apply state-of-the-art ITR learning methods with the flexibility to utilize a subset of covariates, thereby achieving robustness while addressing practical concerns such as fairness. We establish theoretical guarantees, including consistency, the oracle property of treatment fusion, and regret bounds when integrated with multi-armed ITR learning methods such as policy trees. Simulation studies show superior group recovery and policy value compared to existing approaches. We illustrate the practical utility of our method using a nationwide electronic health record-derived de-identified database containing data from patients with Chronic Lymphocytic Leukemia and Small Lymphocytic Lymphoma.
title Doubly Robust Fusion of Many Treatments for Policy Learning
topic Methodology
Machine Learning
url https://arxiv.org/abs/2505.08092