Evaluating and rejecting true mediation models: a cautionary note.
Evaluating and rejecting true mediation models: a cautionary note.
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评估和拒绝真正的调解模型：警告。
DOI：
10.1023/a:1020828709115
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
Herting,JeraldR
中科院分区：
文献类型：
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作者：
Herting,JeraldR
本研究报告描述了一个被忽视的问题，即理解模型中的给定变量是否真正充当某些外生变量和某些最终因变量之间的中介。中介的论证和识别规则依赖于简单的三变量模型，并以明确的直接效应替代模型作为竞争解释。纳入第四个变量表明，当存在真正的调解形式时，拒绝调解是非常简单的。在中介变量和结果变量之间存在不可观察的关系（相关误差）的情况下，三变量模型将始终显示直接影响，而事实上，外生变量没有直接影响。在这种情况下，应用既定规则来测试调解无法区分纯调解被拒绝的模型与真正调解正确的模型。这对巴伦和肯尼程序提供的典型调解评估提出了一个根本问题。
This research note describes an overlooked problem in understanding whether a given variable in a model truly acts as a mediator between some exogenous variable(s) and some final dependent factor. Demonstrations of mediation and the rules for identifying have relied on simple 3-variable models with an explicit direct effects alternative model as the competing explanation. Incorporating a 4th variable demonstrates that it is quite simple to reject mediation when a true form of mediation exists. In the presence of an unobserved relation, correlated error, between mediator variable and outcome variable, the 3-variable model will consistently show direct effects when, in fact, there is no direct effect of the exogenous variable. Applying well-established rules to test for mediation in this circumstance cannot distinguish a model in which pure mediation is rejected from a model in which true mediation is correct. This poses a fundamental problem for the typical assessment of mediation offered by the Baron and Kenny procedures.