The indirect effect is omitted variable bias. A cautionary note on the theoretical interpretation of products-of-coefficients in mediation analyses
Coenen,Lennert
Coenen,Lennert
Abstract
This paper intends to remind communication scientists that the indirect effect as estimated in mediation analyses is a statistical synonym for omitted variable bias (i.e. confounding or suppression). This simple fact questions the interpretability of statistically significant ‘indirect effects’ when using observational data: in social reality, all variables correlate with each other to some extent – the so-called ‘crud factor’ – which means that omitted variable bias and ‘indirect effects’ at the population level are virtually guaranteed regardless of the actual variables involved in the statistical mediation model. As a result, there can be no inferential link between the observation of a significant indirect effect and a theoretical claim of mediation. Through this argument, the paper hopes to add to the existing warnings on mediation analyses and cultivate a more critical interpretation of ‘indirect effects’ in communication science.
Description
Funding Information: The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: Part of the work for this paper was done during a postdoctoral fellowship supported by the Research Foundation – Flanders under Grant 12J7619N. Funding Information: The author would like to thank soon-to-be-dr. Anneleen Meeus and all members of the DCC Statistics Meeting for their useful comments on earlier versions of the manuscript. The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: Part of the work for this paper was done during a postdoctoral fellowship supported by the Research Foundation – Flanders under Grant 12J7619N. Publisher Copyright: © The Author(s) 2022.
Date
2022-12
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Publisher
Research Projects
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Keywords
Mediation analysis, indirect effect, omitted variable bias, significance, statistical inference
Citation
Coenen, L 2022, 'The indirect effect is omitted variable bias. A cautionary note on the theoretical interpretation of products-of-coefficients in mediation analyses', European Journal of Communication, vol. 37, no. 6, 02673231221082244, pp. 679-688. https://doi.org/10.1177/02673231221082244
License
info:eu-repo/semantics/openAccess