Behavior Research Methods

, Volume 46, Issue 4, pp 1184–1198 | Cite as

Monte Carlo based statistical power analysis for mediation models: methods and software

  • Zhiyong ZhangEmail author


The existing literature on statistical power analysis for mediation models often assumes data normality and is based on a less powerful Sobel test instead of the more powerful bootstrap test. This study proposes to estimate statistical power to detect mediation effects on the basis of the bootstrap method through Monte Carlo simulation. Nonnormal data with excessive skewness and kurtosis are allowed in the proposed method. A free R package called bmem is developed to conduct the power analysis discussed in this study. Four examples, including a simple mediation model, a multiple-mediator model with a latent mediator, a multiple-group mediation model, and a longitudinal mediation model, are provided to illustrate the proposed method.


Power analysis Mediation models Nonnormal data Bootstrapping R package bmem 


Author Note

We thank Scott Maxwell and Ke-Hai Yuan for helpful discussions and David Kenny and one anonymous reviewer for constructive suggestions that have significantly improved this research. Path diagrams used in the article were generated using WebSEM (


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Copyright information

© Psychonomic Society, Inc. 2013

Authors and Affiliations

  1. 1.University of Notre DameNotre DameUSA

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