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arXiv 2607.08142stat.ME
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合成控制中的贝叶斯捐赠者集选择

Bayesian Donor Set Selection in Synthetic Controls

Seoul National University(首尔大学);University of Seoul(首尔大学);University of Texas at Arlington(阿灵顿得克萨斯大学)

Seul Lee, Johan Lim, Joungyoun Kim, Xinlei Wang

AI总结:

研究提出贝叶斯层次模型,在合成控制中选择捐赠者集,保持单纯形约束,能同时估计权重与活跃捐赠者集。经数值模拟和实际应用验证,该模型在含无关或弱相关单元时表现良好,为现有方法提供简洁灵活扩展。

摘要:

合成控制方法(SCM)是一种通过使用未处理单元的捐赠者集构建合成反事实来评估干预效果的广泛应用方法。然而,SCM的有效性严重依赖于合适捐赠者集的精心选择。本文提出一种贝叶斯层次模型,在保持对捐赠者权重的标准SCM单纯形约束的同时进行捐赠者集选择。与假设固定捐赠者集的方法不同,该模型允许同时估计合成控制权重和活跃捐赠者集。通过对捐赠者权重使用层次伽马 - 伯努利构造,模型将后验质量分配到单纯形面,并允许排除的捐赠者权重精确为零。在简化的干预前模型下建立了后验捐赠者集一致性结果。通过数值模拟表明,当捐赠者池包含不相关或弱相关单元时,该模型改善了捐赠者恢复和权重估计,在全捐赠者设置中也具有竞争力。最后将模型应用于西德GDP轨迹,说明了其实际适用性。研究结果表明纳入捐赠者集选择为现有贝叶斯合成控制方法提供了更简洁灵活的扩展。

英文摘要:

The Synthetic Control Method (SCM) is a widely used approach for assessing the effects of interventions by constructing a synthetic counterfactual using a donor set of untreated units. However, the effectiveness of SCM heavily relies on the careful selection of an appropriate donor set. In this paper, we propose a Bayesian hierarchical model that performs donor set selection while preserving the standard SCM simplex constraint on donor weights. Unlike approaches that assume a fixed donor set, our model allows for the simultaneous estimation of the synthetic control weights and the active donor set. By using a hierarchical Gamma-Bernoulli construction for the donor weights, the proposed model assigns posterior mass to simplex faces and allows exact zero weights for excluded donors. We establish a posterior donor-set consistency result under a simplified pre-intervention model. Through numerical simulations, we show that our model improves donor recovery and weight estimation when the donor pool contains irrelevant or weakly related units, while remaining competitive in full-donor settings. Finally, we apply our model to the GDP trajectory of West Germany, illustrating its practical applicability. Our findings suggest that incorporating donor set selection offers a more parsimonious and flexible extension of existing Bayesian synthetic control methods.

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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