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Required Sample Size to Detect the Mediated Effect

Overview
Journal Psychol Sci
Specialty Psychology
Date 2007 Apr 21
PMID 17444920
Citations 1100
Authors
Matthew S Fritz
David P MacKinnon
Affiliations
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Abstract

Mediation models are widely used, and there are many tests of the mediated effect. One of the most common questions that researchers have when planning mediation studies is, "How many subjects do I need to achieve adequate power when testing for mediation?" This article presents the necessary sample sizes for six of the most common and the most recommended tests of mediation for various combinations of parameters, to provide a guide for researchers when designing studies or applying for grants.

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References
1.
Shrout P, Bolger N . Mediation in experimental and nonexperimental studies: new procedures and recommendations. Psychol Methods. 2003; 7(4):422-45. View
2.
MacKinnon D, Lockwood C, Williams J . Confidence Limits for the Indirect Effect: Distribution of the Product and Resampling Methods. Multivariate Behav Res. 2010; 39(1):99. PMC: 2821115. DOI: 10.1207/s15327906mbr3901_4. View
3.
MacKinnon D, Fritz M, Williams J, Lockwood C . Distribution of the product confidence limits for the indirect effect: program PRODCLIN. Behav Res Methods. 2007; 39(3):384-9. PMC: 2819369. DOI: 10.3758/bf03193007. View
4.
Cole D, Maxwell S . Testing mediational models with longitudinal data: questions and tips in the use of structural equation modeling. J Abnorm Psychol. 2003; 112(4):558-77. DOI: 10.1037/0021-843X.112.4.558. View
5.
Holmbeck G . Toward terminological, conceptual, and statistical clarity in the study of mediators and moderators: examples from the child-clinical and pediatric psychology literatures. J Consult Clin Psychol. 1997; 65(4):599-610. DOI: 10.1037//0022-006x.65.4.599. View