Researcher allegiance in psychotherapy outcome research: an overview of reviews

Thomas Munder, Oliver Brütsch, Rainer Leonhart, Heike Gerger, Jürgen Barth

Research output: Contribution to journalArticleAcademicpeer-review

185 Citations (Scopus)


Researcher allegiance (RA) is widely discussed as a risk of bias in psychotherapy outcome research. The relevance attached to RA bias is related to meta-analyses demonstrating an association of RA with treatment effects. However, recent meta-analyses have yielded mixed results. To provide more clarity on the magnitude and robustness of the RA-outcome association this article reports on a meta-meta-analysis summarizing all available meta-analytic estimates of the RA-outcome association. Random-effects methods were used. Primary study overlap was controlled. Thirty meta-analyses were included. The mean RA-outcome association was r=.262 (p=.002, I(2)=28.98%), corresponding to a moderate effect size. The RA-outcome association was robust across several moderating variables including characteristics of treatment, population, and the type of RA assessment. Allegiance towards the RA bias hypothesis moderated the RA-outcome association. The findings of this meta-meta-analysis suggest that the RA-outcome association is substantial and robust. Implications for psychotherapy outcome research are discussed.

Original languageEnglish
Pages (from-to)501-11
Number of pages11
JournalClinical Psychology Review
Issue number4
Publication statusPublished - Jun 2013

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Copyright © 2013 Elsevier Ltd. All rights reserved.


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