Assumptions and Consequences of Treating Providers in Therapy Studies as Fixed Versus Random Effects: Reply to Crits-Christoph, Tu, and Gallop (2003) and Serlin, Wampold, and Levin (2003)

Matthias Siemer, Jutta Joormann

Research output: Contribution to journalArticle

13 Scopus citations


In their comments on the authors' article (M. Siemer & J. Joormann, 2003), R. C. Serlin, B. E. Wampold, and J. R. Levin (2003) and P. Crits-Christoph, X. Tu, and R. Gallop (2003) took issue with the authors' suggestion to evaluate therapy studies with nested providers with a fixed model approach. In this reply, the authors comment on Serlin et al.'s critique by showing that their arguments do not apply, are based on misconceptions about the purpose and nature of statistical inference, or are based on flawed reasoning. The authors also comment on Crits-Christoph et al.'s critique by showing that the proposed approach is very similar to, but less inclusive than, their own suggestion.

Original languageEnglish (US)
Pages (from-to)535-544
Number of pages10
JournalPsychological Methods
Issue number4
StatePublished - Dec 1 2003


ASJC Scopus subject areas

  • Psychology (miscellaneous)

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