Abstract

Mediation analysis is widely used to identify significant mediators and estimate the mediation (direct and indirect) effects in causal pathways between an exposure variable and a response variable. In mediation analysis, the mediation effect refers to the effect transmitted by mediator intervening the relationship between an exposure variable and a response variable. Traditional mediation analysis methods, such as the difference in the coefficient method, the product of the coefficient method, and counterfactual framework method, all require several key assumptions. Thus, the estimation of mediation effects can be biased when one or more assumptions are violated. In addition to the traditional mediation analysis methods, Yu et al. proposed a general mediation analysis method that can use general predictive models to estimate mediation effects of any types of exposure variable(s), mediators and outcome(s). However, whether this method relies on the assumptions for the traditional mediation analysis methods is unknown. In this paper, we perform series of simulation studies to investigate the impact of violation of assumptions on the estimation of mediation effects using Yu et al.’s mediation analysis method. We use the R package mma for all estimations. We find that three assumptions for traditional mediation analysis methods are also essential for Yu et al.’s method. This paper provides a pipeline for using simulations to evaluate the impact of the assumptions for the general mediation analysis.

 抽象的

中介分析广泛用于识别重要中介因素并估计暴露变量和响应变量之间因果路径中的中介（直接和间接）影响。在中介分析中，中介效应是指中介者干预暴露变量和响应变量之间关系所传递的效应。传统的中介分析方法，如系数差法、系数乘积法、反事实框架法等，都需要几个关键假设。因此，当违反一个或多个假设时，中介效应的估计可能会出现偏差。除了传统的中介分析方法之外，Yu 等人。提出了一种通用的中介分析方法，可以使用通用的预测模型来估计任何类型的暴露变量、中介和结果的中介效应。然而，该方法是否依赖于传统中介分析方法的假设尚不清楚。在本文中，我们使用Yu等人的中介分析方法进行了一系列模拟研究，以研究违反假设对中介效应估计的影响。我们使用 R 包mma进行所有估计。我们发现传统中介分析方法的三个假设对于 Yu 等人的方法也是必不可少的。本文提供了一个使用模拟来评估一般中介分析假设的影响的管道。