WHOMP: Optimizing Randomized Controlled Trials via Wasserstein Homogeneity

Fuente: arXiv
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Main Authors: Xu, Shizhou, Strohmer, Thomas
Format: Preprint
Published: 2024
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author Xu, Shizhou
Strohmer, Thomas
author_facet Xu, Shizhou
Strohmer, Thomas
contents We investigate methods for partitioning datasets into subgroups that maximize diversity within each subgroup while minimizing dissimilarity across subgroups. We introduce a novel partitioning method called the $\textit{Wasserstein Homogeneity Partition}$ (WHOMP), which optimally minimizes type I and type II errors that often result from imbalanced group splitting or partitioning, commonly referred to as accidental bias, in comparative and controlled trials. We conduct an analytical comparison of WHOMP against existing partitioning methods, such as random subsampling, covariate-adaptive randomization, rerandomization, and anti-clustering, demonstrating its advantages. Moreover, we characterize the optimal solutions to the WHOMP problem and reveal an inherent trade-off between the stability of subgroup means and variances among these solutions. Based on our theoretical insights, we design algorithms that not only obtain these optimal solutions but also equip practitioners with tools to select the desired trade-off. Finally, we validate the effectiveness of WHOMP through numerical experiments, highlighting its superiority over traditional methods.
format Preprint
id arxiv_https___arxiv_org_abs_2409_18504
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle WHOMP: Optimizing Randomized Controlled Trials via Wasserstein Homogeneity
Xu, Shizhou
Strohmer, Thomas
Machine Learning
Probability
Statistics Theory
We investigate methods for partitioning datasets into subgroups that maximize diversity within each subgroup while minimizing dissimilarity across subgroups. We introduce a novel partitioning method called the $\textit{Wasserstein Homogeneity Partition}$ (WHOMP), which optimally minimizes type I and type II errors that often result from imbalanced group splitting or partitioning, commonly referred to as accidental bias, in comparative and controlled trials. We conduct an analytical comparison of WHOMP against existing partitioning methods, such as random subsampling, covariate-adaptive randomization, rerandomization, and anti-clustering, demonstrating its advantages. Moreover, we characterize the optimal solutions to the WHOMP problem and reveal an inherent trade-off between the stability of subgroup means and variances among these solutions. Based on our theoretical insights, we design algorithms that not only obtain these optimal solutions but also equip practitioners with tools to select the desired trade-off. Finally, we validate the effectiveness of WHOMP through numerical experiments, highlighting its superiority over traditional methods.
title WHOMP: Optimizing Randomized Controlled Trials via Wasserstein Homogeneity
topic Machine Learning
Probability
Statistics Theory
url https://arxiv.org/abs/2409.18504