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arXiv 2602.07613stat.MEstat.COstat.ML

快速重随机化用于随机实验中协变量的平衡:一个Metropolis-Hastings框架

Fast Rerandomization for Balancing Covariates in Randomized Experiments: A Metropolis-Hastings Framework

Jiuyao Lu, Tianruo Zhang, Ke Zhu

AI总结:

本文提出PSRSRR算法,基于Metropolis-Hastings框架,通过引入采样-重要性重采样步骤,实现快速且有效的协变量平衡,提升随机实验的效率和准确性。

摘要:

在随机实验中平衡协变量对于获得可信和高效的实验结果至关重要。重随机化通过反复生成处理分配,直到协变量平衡达到预设的阈值来解决这一问题。通过缩小这个阈值,可以实现任意强的平衡,已有结果保证了在有限样本和渐近情况下,无论复杂实验环境如何,都能获得最优的估计和有效的推断。尽管其理论基础严谨,但实际应用却受到拒绝采样极端低效的限制,当阈值较小时,这种低效变得不可接受,通常迫使从业者采用次优设置,导致性能下降。现有工作在加速方面的研究通常无法保持可接受分配空间的均匀性,因此失去了经典重随机化的理论基础。基于Metropolis-Hastings框架,我们通过引入额外的采样-重要性重采样步骤来解决这一挑战,恢复了均匀性并保持了统计保证。我们提出的方法PSRSRR在模拟和两个真实数据应用中展示了从10到10000倍的速度提升,同时保持了精确性和渐近有效性。

英文摘要:

Balancing covariates is critical for credible and efficient randomized experiments. Rerandomization addresses this by repeatedly generating treatment assignments until covariate balance meets a prespecified threshold. By shrinking this threshold, it can achieve arbitrarily strong balance, with established results guaranteeing optimal estimation and valid inference in both finite-sample and asymptotic settings across diverse complex experimental settings. Despite its rigorous theoretical foundations, practical use is limited by the extreme inefficiency of rejection sampling, which becomes prohibitively slow under small thresholds and often forces practitioners to adopt suboptimal settings, leading to degraded performance. Existing work focusing on acceleration typically fail to maintain the uniformity over the acceptable assignment space, thus losing the theoretical grounds of classical rerandomization. Building upon a Metropolis-Hastings framework, we address this challenge by introducing an additional sampling-importance resampling step, which restores uniformity and preserves statistical guarantees. Our proposed algorithm, PSRSRR, achieves speedups ranging from 10 to 10,000 times while maintaining exact and asymptotic validity, as demonstrated by simulations and two real-data applications.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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