Testing Multilevel Mediation Using Hierarchical Linear Models
总结了三种基于分层线性模型的多层次中介模型，指出其中两种在组内效应与组间效应不同时会产生混淆，导致中介效应被高估或低估，并给出正确检验的建议。
Testing multilevel mediation using hierarchical linear modeling (HLM) has gained tremendous popularity in recent years. However, potential confounding in multilevel mediation effect estimates can arise in these models when within-group effects differ from between-group effects. This study summarizes three types of HLM-based multilevel mediation models, and then explains that in two types of these models confounding can be produced and erroneous conclusions may be derived when using popularly recommended procedures. A Monte Carlo simulation study illustrates that these procedures can underestimate or overestimate true mediation effects. Recommendations are provided for appropriately testing multilevel mediation and for differentiating within-group versus between-group effects in multilevel settings.