It is often of interest in the health and social sciences to investigate the joint mediation effects of multiple post-exposure mediating variables. Identification of such joint mediation effects generally require no unmeasured confounding of the outcome with respect to the whole set of mediators. As the number of mediators under consideration grows, this key assumption is likely to be violated as it is often infeasible to intervene on any of the mediators. In this paper, we develop a simple two-step method of moments estimation procedure to assess mediation with multiple mediators simultaneously in the presence of potential unmeasured mediator-outcome confounding. Our identification result leverages heterogeneity of the exposure effect on each mediator in the population, which is plausible under a variety of empirical settings. The proposed estimators are illustrated through both simulations and an application to evaluate the mediating effects of post-traumatic stress disorder symptoms in the association between self-efficacy and fatigue among health care workers during the COVID-19 outbreak.
翻译:调查多个接触后调解变数的共同调解影响往往与卫生和社会科学有关,调查多个接触后调解变数的共同调解影响往往与卫生和社会科学有关。确定这类联合调解影响通常不需要对整体调解人的结果进行不测的混淆。随着审议中的调解人人数的增加,这一关键假设很可能遭到违反,因为对任何调解人往往都无法进行干预。在本文件中,我们制定了一个简单的时间估计程序两步方法,以便在潜在无法计量的调解人无法解答的情况下,同时评估与多个调解人的调解。我们的确定结果利用了接触影响对人口中每个调解人的不同特性,在各种经验环境中,这一点是可信的。拟议的估计数字通过模拟和运用来说明,评价创伤后应激障碍症状在COVID-19爆发期间与保健工作者自我效能和疲劳之间的联系中的调解影响。