Model-assisted analysis of covariance estimators for stepped wedge cluster randomized experiments

Fuente: arXiv
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Auteurs principaux: Chen, Xinyuan, Li, Fan
Format: Preprint
Publié: 2023
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author Chen, Xinyuan
Li, Fan
author_facet Chen, Xinyuan
Li, Fan
contents Stepped wedge cluster randomized experiments (SW-CREs) represent a class of unidirectional crossover designs. Although SW-CREs have become popular, definitions of estimands and robust methods to target estimands under the potential outcomes framework remain insufficient. To address this gap, we describe a class of estimands that explicitly acknowledge the multilevel data structure in SW-CREs and highlight three typical members of the estimand class that are interpretable. We then introduce four analysis of covariance (ANCOVA) working models to achieve estimand-aligned analyses with covariate adjustment. Each ANCOVA estimator is model-assisted, as its point estimator is consistent even when the working model is misspecified. Under the stepped wedge randomization scheme, we establish the finite population Central Limit Theorem for each estimator. We study the finite-sample operating characteristics of the ANCOVA estimators in simulations and illustrate their application by analyzing the Washington State Expedited Partner Therapy study.
format Preprint
id arxiv_https___arxiv_org_abs_2306_11267
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Model-assisted analysis of covariance estimators for stepped wedge cluster randomized experiments
Chen, Xinyuan
Li, Fan
Methodology
Applications
Stepped wedge cluster randomized experiments (SW-CREs) represent a class of unidirectional crossover designs. Although SW-CREs have become popular, definitions of estimands and robust methods to target estimands under the potential outcomes framework remain insufficient. To address this gap, we describe a class of estimands that explicitly acknowledge the multilevel data structure in SW-CREs and highlight three typical members of the estimand class that are interpretable. We then introduce four analysis of covariance (ANCOVA) working models to achieve estimand-aligned analyses with covariate adjustment. Each ANCOVA estimator is model-assisted, as its point estimator is consistent even when the working model is misspecified. Under the stepped wedge randomization scheme, we establish the finite population Central Limit Theorem for each estimator. We study the finite-sample operating characteristics of the ANCOVA estimators in simulations and illustrate their application by analyzing the Washington State Expedited Partner Therapy study.
title Model-assisted analysis of covariance estimators for stepped wedge cluster randomized experiments
topic Methodology
Applications
url https://arxiv.org/abs/2306.11267