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arXiv 2108.08417stat.ME
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用乘积法估算自然间接效应和中介比例

Estimating the natural indirect effect and the mediation proportion via the product method

Chao Cheng, Donna Spiegelman, Fan Li

摘要:

自然间接效应(NIE)和中介比例(MP)是中介分析的两个重要指标。估计NIE和MP的标准方法是通过乘积法,其中包括一个以中介和暴露为条件的结果模型,以及另一个描述确定性-中介关系的模型。本文的目的是全面发展和研究有限样本性能的NIE和MP估计通过产品的方法。针对四种常见的数据类型,利用估计方程理论和多元delta方法,提出了封闭形式的区间估计,并评价了其相对于Bootstrap方法的经验性能.此外,我们还观察到,罕见结局假设经常被用来近似具有二元结局的NIE和MP,尽管当结局常见时,这种近似可能导致不可忽略的偏倚。因此,我们介绍了确切的表达NIE和MP的二元结果没有罕见的结果假设,并比较其性能与近似估计。基于这些理论发展和实证研究,我们提供了一些实用的建议,以告知实践。为了实现本文所讨论的点估计和方差估计方法,开发了一个R软件包mediateP。

英文摘要:

The natural indirect effect (NIE) and mediation proportion (MP) are two measures of primary interest in mediation analysis. The standard approach for estimating NIE and MP is through the product method, which involves a model for the outcome conditional on the mediator and exposure and another model describing the exposure-mediator relationship. The purpose of this article is to comprehensively develop and investigate the finite-sample performance of NIE and MP estimators via the product method. With four common data types, we propose closed-form interval estimators via the theory of estimating equations and multivariate delta method, and evaluate its empirical performance relative to the bootstrap approach. In addition, we have observed that the rare outcome assumption is frequently invoked to approximate the NIE and MP with a binary outcome, although this approximation may lead to non-negligible bias when the outcome is common. We therefore introduce the exact expressions for NIE and MP with a binary outcome without the rare outcome assumption and compare its performance with the approximate estimators. Based upon these theoretical developments and empirical studies, we offer several practical recommendations to inform practice. An R package mediateP is developed to implement the methods for point and variance estimation discussed in this paper.

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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