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arXiv 2109.04154econ.EM
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基于结果自适应随机森林的因果推断变量选择

Variable Selection for Causal Inference via Outcome-Adaptive Random Forest

Daniel Jacob

摘要:

如果我们不控制自我选择,那么从观察数据中估计因果效应可能会有偏差。该选择基于影响治疗分配和结局的混杂变量。倾向评分方法旨在校正混杂因素。然而,并非所有协变量都是混杂因素。我们提出的结果自适应随机森林(OARF),只包括期望的变量估计的倾向得分,以减少偏差和方差。我们的方法适用于高维数据集,如果结果和倾向评分模型是非线性的,可能很复杂。OARF排除了与结果无关的协变量,即使存在大量虚假变量。仿真结果表明,OARF产生无偏估计,有一个较小的方差,是优于其他方法相比,在变量选择。从两个经验性的例子,右心导管插入术对死亡率的影响和母亲在怀孕期间吸烟对出生体重的影响,结果显示类似的处理效应,以前的研究结果,但更严格的置信区间和更合理的选择变量。

英文摘要:

Estimating a causal effect from observational data can be biased if we do not control for self-selection. This selection is based on confounding variables that affect the treatment assignment and the outcome. Propensity score methods aim to correct for confounding. However, not all covariates are confounders. We propose the outcome-adaptive random forest (OARF) that only includes desirable variables for estimating the propensity score to decrease bias and variance. Our approach works in high-dimensional datasets and if the outcome and propensity score model are non-linear and potentially complicated. The OARF excludes covariates that are not associated with the outcome, even in the presence of a large number of spurious variables. Simulation results suggest that the OARF produces unbiased estimates, has a smaller variance and is superior in variable selection compared to other approaches. The results from two empirical examples, the effect of right heart catheterization on mortality and the effect of maternal smoking during pregnancy on birth weight, show comparable treatment effects to previous findings but tighter confidence intervals and more plausible selected variables.

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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