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Meta-analysis

Often, a large number of studies is available on a psychological issue. The method of meta-analysis provides a systematic approach for quantitatively integrating the findings of different primary studies into an overall result. The strength of the method lies in a transparent multi-step procedure: Definition of criteria for studies to be included, comprehensive literature search, coding of effects and characteristics of primary studies, integration of study results into an overall effect, and moderator analyses.

In our research, we are developing the R package "metaBMA" for Bayesian analysis of meta-analyses. To test whether there is an effect in the population, Bayesian statistics allows to quantify evidence for the alternative hypothesis as well as for the null hypothesis. Furthermore, with the help of "Bayesian Model Averaging" it is possible to integrate meta-analytical models with different statistical assumptions (fixed-effects versus random-effects). We also address the methodological question of how mediation processes and hypotheses can be most appropriately investigated meta-analytically. In terms of thematic research matters, we apply meta-analysis to meta-analytically summarize the findings of contact interventions to reduce ethnic prejudice. We are also particularly interested in how the effects of studies with different research designs can be most appropriately mapped and integrated.

Publications on Bayesian meta-analysis:

  • Berkhout, S. W., Haaf, J. M., Gronau, Q. F., Heck, D. W., & Wagenmakers, E. (2021). A tutorial on Bayesian model-averaged meta-analysis in JASP. PsyArXiv. https://psyarxiv.com/ne8dw/
  • Gronau, Q. F., Erp, S. V., Heck, D. W., Cesario, J., Jonas, K. J., & Wagenmakers, E. (2017). A Bayesian model-averaged meta-analysis of the power pose effect with informed and default priors: the case of felt power. Comprehensive Results in Social Psychology, 2, 123-138. https://doi.org/10.1080/23743603.2017.1326760
  • Gronau, Q. F., Heck, D. W., Berkhout, S. W., Haaf, J. M., & Wagenmakers, E. (2021). A primer on Bayesian model-averaged meta-analysis. Advances in Methods and Practices in Psychological Science, 4, 1–19. https://doi.org/10.1177/25152459211031256
  • Heck, D. W., & Gronau, Q. F. (2017). metaBMA: Bayesian model averaging for random- and fixed-effects meta-analysis. Retrieved from https://cran.r-project.org/package=metaBMA

Publications on the application of meta-analysis:

  • Lemmer, G., & Wagner, U. (2015). Can we really reduce ethnic prejudice outside the lab?  A meta-analysis of direct and indirect contact interventions. European Journal of Social Psychology, 45, 152-168.
  • Lemmer, G., & Wagner, U. (2014, July). The effect of indirect contact on intergroup relations: A meta-analysis. 17th European Association of Social Psychology General Meeting. Amsterdam, the Netherlands.
  • Schwinger, M., Wirthwein, L., Lemmer, G., & Steinmayr. R. (2014). Academic self-handicapping and achievement: A meta-analysis. Journal of Educational Psychology, 106, 744-761.