Optimality of Matched-Pair Designs in Randomized Controlled Trials

Yuehao Bai

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arXiv · 2206.07845

Optimality of Matched-Pair Designs in Randomized Controlled Trials

Yuehao Bai

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Abstract

In randomized controlled trials (RCTs), treatment is often assigned by stratified randomization. I show that among all stratified randomization schemes which treat all units with probability one half, a certain matched-pair design achieves the maximum statistical precision for estimating the average treatment effect (ATE). In an important special case, the optimal design pairs units according to the baseline outcome. In a simulation study based on datasets from 10 RCTs, this design lowers the standard error for the estimator of the ATE by 10% on average, and by up to 34%, relative to the original designs.

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Yuehao Bai. 2022-06-15. Optimality of Matched-Pair Designs in Randomized Controlled Trials. https://arxiv.org/abs/2206.07845

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