A General Approach to Causal Mediation Analysis
A General Approach to Causal Mediation Analysis
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DOI：
10.1037/a0020761
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发表时间：
2010-12-01
影响因子：
7
通讯作者：
Tingley, Dustin
中科院分区：
文献类型：
--
作者：
Imai, Kosuke;Keele, Luke;Tingley, Dustin
在社会科学领域，传统上因果中介分析是在线性结构方程模型的框架内被构建、理解和实施的。我们认为并证明这存在三个问题：缺乏独立于特定统计模型的因果中介效应的通用定义，无法明确关键的识别假设，以及难以将该框架扩展到非线性模型。在本文中，我们提出一种替代方法，克服了这些局限性。我们的方法具有通用性，因为它在不涉及任何特定统计模型的情况下，提供了因果中介效应的定义、识别、估计和敏感性分析。此外，我们的方法在一个单一框架内将这四个要素紧密明确地联系在一起。因此，所提出的框架能够适应线性和非线性关系、参数和非参数模型、连续和离散的中介变量以及各种类型的结果变量。通用定义和识别结果还使我们能够在常用模型的背景下开展敏感性分析，这使得应用研究人员能够正式评估其实证结论在关键假设不成立时的稳健性。我们通过将其应用于求职干预研究来说明我们的方法。我们还提供了易于使用的软件，该软件实现了我们提出的所有方法。
Traditionally in the social sciences, causal mediation analysis has been formulated, understood, and implemented within the framework of linear structural equation models. We argue and demonstrate that this is problematic for 3 reasons: the lack of a general definition of causal mediation effects independent of a particular statistical model, the inability to specify the key identification assumption, and the difficulty of extending the framework to nonlinear models. In this article, we propose an alternative approach that overcomes these limitations. Our approach is general because it offers the definition, identification, estimation, and sensitivity analysis of causal mediation effects without reference to any specific statistical model. Further, our approach explicitly links these 4 elements closely together within a single framework. As a result, the proposed framework can accommodate linear and nonlinear relationships, parametric and nonparametric models, continuous and discrete mediators, and various types of outcome variables. The general definition and identification result also allow us to develop sensitivity analysis in the context of commonly used models, which enables applied researchers to formally assess the robustness of their empirical conclusions to violations of the key assumption. We illustrate our approach by applying it to the Job Search Intervention Study. We also offer easy-to-use software that implements all our proposed methods.