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arXiv 2008.00507stat.ME
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估计二元治疗因果效应的双重稳健和有效方法

Double-robust and efficient methods for estimating the causal effects of a binary treatment

James Robins, Mariela Sued, Quanhong Lei-Gomez, Andrea Rotnitzky

摘要:

我们考虑的问题是,在没有不可测因素混杂的情况下,从观察数据中估计二元治疗对连续结果的影响。我们提供了一个新的估计群体平均处理效应(ATE)的基础上的差异,新的双稳健(DR)估计的治疗特异性结果的手段。我们比较我们的新的估计与以前的估计理论上和通过模拟。当治疗组和未治疗组的估计倾向得分不重叠时,DR差异估计值可能具有较差的有限样本行为。因此,我们提出了一种替代方法,即使在这种不利的情况下也可以使用,该方法基于半参数回归模型的局部有效双稳健估计,用于通过基线协变量$X$对处理效应幅度的加性尺度进行修改。与现有方法相比,我们的方法同时提供以下估计值:i)总研究人群的平均处理效应,ii)具有重叠估计倾向得分的人群随机子集的平均处理效应,以及iii)基线协变量$X$每个水平的处理效应。当协变量向量$X$为高维时,由于缺乏功效,无法确定给定的倾向得分和治疗结局回归模型以及用于构建DR估计量的$X$几乎是正确的,即使它们通过了标准拟合优度检验。因此,在候选模型中进行选择,我们提出了一种新的模型选择方法,该方法利用了我们的处理效应估计量的DR性质,并且在小型模拟研究中优于交叉验证。

英文摘要:

We consider the problem of estimating the effects of a binary treatment on a continuous outcome of interest from observational data in the absence of confounding by unmeasured factors. We provide a new estimator of the population average treatment effect (ATE) based on the difference of novel double-robust (DR) estimators of the treatment-specific outcome means. We compare our new estimator with previously estimators both theoretically and via simulation. DR-difference estimators may have poor finite sample behavior when the estimated propensity scores in the treated and untreated do not overlap. We therefore propose an alternative approach, which can be used even in this unfavorable setting, based on locally efficient double-robust estimation of a semiparametric regression model for the modification on an additive scale of the magnitude of the treatment effect by the baseline covariates $X$. In contrast with existing methods, our approach simultaneously provides estimates of: i) the average treatment effect in the total study population, ii) the average treatment effect in the random subset of the population with overlapping estimated propensity scores, and iii) the treatment effect at each level of the baseline covariates $X$. When the covariate vector $X$ is high dimensional, one cannot be certain, owing to lack of power, that given models for the propensity score and for the regression of the outcome on treatment and $X$ used in constructing our DR estimators are nearly correct, even if they pass standard goodness of fit tests. Therefore to select among candidate models, we propose a novel approach to model selection that leverages the DR-nature of our treatment effect estimator and that outperforms cross-validation in a small simulation study.

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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