A Viable Alternative When Propensity Scores Fail: Evaluation of Inverse Propensity Weighting and Sequential G-Estimation in a Two-Wave Mediation Model.
A Viable Alternative When Propensity Scores Fail: Evaluation of Inverse Propensity Weighting and Sequential G-Estimation in a Two-Wave Mediation Model.
复制标题
倾向得分失败时的可行替代方案：两波中介模型中逆倾向加权和序贯 G 估计的评估。
DOI：
10.1080/00273171.2019.1614429
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发表时间：
2020
影响因子：
3.8
通讯作者：
Mazza,GinaL
中科院分区：
文献类型：
--
作者：
Valente,MatthewJ;MacKinnon,DavidP;Mazza,GinaL
两种方法从潜在的结果框架-逆倾向加权（IPW）和序贯G-估计-进行了评估，并与线性回归估计介导的影响，在两波设计与随机干预和连续的调解人和结果。调解人和结果的基线措施可以被认为是后续的调解结果的关系，调整是必要的，以消除偏见的混杂因素。为了调整中介和结果的基线测量，IPW使用稳定的逆倾向权重，而序贯G估计使用回归调整。模型之间的理论差异进行了描述，和蒙特卡洛模拟比较线性回归的性能; IPW没有重量截断; IPW的重量截断在第1/99，第5/95，和第10/90次的位数;和顺序G估计。序贯G-估计的表现与线性回归相似，但IPW提供了介导效应的偏倚估计、较低的功效、较低的置信区间覆盖率和较高的均方误差。模拟结果表明，IPW未能完全调整后续的中介结果关系的混杂，由于基线措施。然后，我们比较了介导效应的估计使用的数据从一个随机实验评估类固醇预防计划的高中运动员。影响和未来的方向进行了讨论。
Two methods from the potential outcomes framework – inverse propensity weighting (IPW) and sequential G-estimation – were evaluated and compared to linear regression for estimating the mediated effect in a two-wave design with a randomized intervention and continuous mediator and outcome. Baseline measures of the mediator and outcome can be considered confounders of the follow-up mediator – outcome relation for which adjustment is necessary to eliminate bias. To adjust for baseline measures of the mediator and outcome, IPW uses stabilized inverse propensity weights whereas sequential G-estimation uses regression adjustment. Theoretical differences between the models are described, and Monte Carlo simulations compared the performance of linear regression; IPW without weight truncation; IPW with weights truncated at the 1st/99th, 5th/95th, and 10th/90th percentiles; and sequential G-estimation. Sequential G-estimation performed similarly to linear regression, but IPW provided a biased estimate of the mediated effect, lower power, lower confidence interval coverage, and higher mean squared error. Simulation results show that IPW failed to fully adjust the follow-up mediator – outcome relation for confounding due to the baseline measures. We then compared the mediated effect estimates using data from a randomized experiment evaluating a steroid prevention program for high school athletes. Implications and future directions are discussed.