A Universal Framework for Factorial Matched Observational Studies with General Treatment Types: Design, Analysis, and Applications

Fuente: arXiv
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Main Authors: Zhu, Jianan, Zhang, Tianruo, Silver, Diana, Matthay, Ellicott, El-Shahawy, Omar, Kang, Hyunseung, Heng, Siyu
Format: Preprint
Published: 2025
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author Zhu, Jianan
Zhang, Tianruo
Silver, Diana
Matthay, Ellicott
El-Shahawy, Omar
Kang, Hyunseung
Heng, Siyu
author_facet Zhu, Jianan
Zhang, Tianruo
Silver, Diana
Matthay, Ellicott
El-Shahawy, Omar
Kang, Hyunseung
Heng, Siyu
contents Matching is one of the most widely used causal inference frameworks in observational studies. However, all the existing matching-based causal inference methods are designed for either a single treatment with general treatment types (e.g., binary, ordinal, or continuous) or factorial (multiple) treatments with binary treatments only. To our knowledge, no existing matching-based causal methods can handle factorial treatments with general treatment types. This critical gap substantially hinders the applicability of matching in many real-world problems, in which there are often multiple, potentially non-binary (e.g., continuous) treatment components. To address this critical gap, this work develops a universal framework for the design and analysis of factorial matched observational studies with general treatment types (e.g., binary, ordinal, or continuous). We first propose a two-stage non-bipartite matching algorithm that constructs matched sets of units with similar covariates but distinct combinations of treatment doses, thereby enabling valid estimation of both main and interaction effects. We then introduce a new class of generalized factorial Neyman-type estimands that provide model-free, finite-population-valid definitions of marginal and interaction causal effects under factorial treatments with general treatment types. Randomization-based Fisher-type and Neyman-type inference procedures are developed, including unbiased estimators, asymptotically valid variance estimators, and variance adjustments incorporating covariate information for improved efficiency. Finally, we illustrate the proposed framework through a county-level application that evaluates the causal impacts of work- and non-work-trip reductions (social distancing practices) on COVID-19-related and drug-related outcomes during the COVID-19 pandemic in the United States.
format Preprint
id arxiv_https___arxiv_org_abs_2512_18997
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A Universal Framework for Factorial Matched Observational Studies with General Treatment Types: Design, Analysis, and Applications
Zhu, Jianan
Zhang, Tianruo
Silver, Diana
Matthay, Ellicott
El-Shahawy, Omar
Kang, Hyunseung
Heng, Siyu
Methodology
Applications
Matching is one of the most widely used causal inference frameworks in observational studies. However, all the existing matching-based causal inference methods are designed for either a single treatment with general treatment types (e.g., binary, ordinal, or continuous) or factorial (multiple) treatments with binary treatments only. To our knowledge, no existing matching-based causal methods can handle factorial treatments with general treatment types. This critical gap substantially hinders the applicability of matching in many real-world problems, in which there are often multiple, potentially non-binary (e.g., continuous) treatment components. To address this critical gap, this work develops a universal framework for the design and analysis of factorial matched observational studies with general treatment types (e.g., binary, ordinal, or continuous). We first propose a two-stage non-bipartite matching algorithm that constructs matched sets of units with similar covariates but distinct combinations of treatment doses, thereby enabling valid estimation of both main and interaction effects. We then introduce a new class of generalized factorial Neyman-type estimands that provide model-free, finite-population-valid definitions of marginal and interaction causal effects under factorial treatments with general treatment types. Randomization-based Fisher-type and Neyman-type inference procedures are developed, including unbiased estimators, asymptotically valid variance estimators, and variance adjustments incorporating covariate information for improved efficiency. Finally, we illustrate the proposed framework through a county-level application that evaluates the causal impacts of work- and non-work-trip reductions (social distancing practices) on COVID-19-related and drug-related outcomes during the COVID-19 pandemic in the United States.
title A Universal Framework for Factorial Matched Observational Studies with General Treatment Types: Design, Analysis, and Applications
topic Methodology
Applications
url https://arxiv.org/abs/2512.18997