Inference in Cluster Randomized Trials with Matched Pairs

Fuente: arXiv
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Autori principali: Bai, Yuehao, Liu, Jizhou, Shaikh, Azeem M., Tabord-Meehan, Max
Natura: Preprint
Pubblicazione: 2022
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author Bai, Yuehao
Liu, Jizhou
Shaikh, Azeem M.
Tabord-Meehan, Max
author_facet Bai, Yuehao
Liu, Jizhou
Shaikh, Azeem M.
Tabord-Meehan, Max
contents This paper studies inference in cluster randomized trials where treatment status is determined according to a "matched pairs" design. Here, by a cluster randomized experiment, we mean one in which treatment is assigned at the level of the cluster; by a "matched pairs" design, we mean that a sample of clusters is paired according to baseline, cluster-level covariates and, within each pair, one cluster is selected at random for treatment. We study the large-sample behavior of a weighted difference-in-means estimator and derive two distinct sets of results depending on if the matching procedure does or does not match on cluster size. We then propose a single variance estimator which is consistent in either regime. Combining these results establishes the asymptotic exactness of tests based on these estimators. Next, we consider the properties of two common testing procedures based on t-tests constructed from linear regressions, and argue that both are generally conservative in our framework. We additionally study the behavior of a randomization test which permutes the treatment status for clusters within pairs, and establish its finite-sample and asymptotic validity for testing specific null hypotheses. Finally, we propose a covariate-adjusted estimator which adjusts for additional baseline covariates not used for treatment assignment, and establish conditions under which such an estimator leads to strict improvements in precision. A simulation study confirms the practical relevance of our theoretical results.
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id arxiv_https___arxiv_org_abs_2211_14903
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Inference in Cluster Randomized Trials with Matched Pairs
Bai, Yuehao
Liu, Jizhou
Shaikh, Azeem M.
Tabord-Meehan, Max
Econometrics
Methodology
This paper studies inference in cluster randomized trials where treatment status is determined according to a "matched pairs" design. Here, by a cluster randomized experiment, we mean one in which treatment is assigned at the level of the cluster; by a "matched pairs" design, we mean that a sample of clusters is paired according to baseline, cluster-level covariates and, within each pair, one cluster is selected at random for treatment. We study the large-sample behavior of a weighted difference-in-means estimator and derive two distinct sets of results depending on if the matching procedure does or does not match on cluster size. We then propose a single variance estimator which is consistent in either regime. Combining these results establishes the asymptotic exactness of tests based on these estimators. Next, we consider the properties of two common testing procedures based on t-tests constructed from linear regressions, and argue that both are generally conservative in our framework. We additionally study the behavior of a randomization test which permutes the treatment status for clusters within pairs, and establish its finite-sample and asymptotic validity for testing specific null hypotheses. Finally, we propose a covariate-adjusted estimator which adjusts for additional baseline covariates not used for treatment assignment, and establish conditions under which such an estimator leads to strict improvements in precision. A simulation study confirms the practical relevance of our theoretical results.
title Inference in Cluster Randomized Trials with Matched Pairs
topic Econometrics
Methodology
url https://arxiv.org/abs/2211.14903