Well, that's a good question. It actually applies to many different contexts (not just meta-analysis). Think of the ANOVA F-test and post-hoc/planned contrasts. It's essentially the same situation. And if you would ask 10 different statisticians about this, you may get 11 different answers.
My suggestion would be this: If you have no particular hypotheses in mind and are just screening for group differences, then adjust. If you have a priori hypotheses, then test them without adjustment (and in that case, you may even ignore the omnibus test). Best, -- Wolfgang Viechtbauer Department of Psychiatry and Neuropsychology School for Mental Health and Neuroscience Maastricht University, P.O. Box 616 6200 MD Maastricht, The Netherlands Tel: +31 (43) 368-5248 Fax: +31 (43) 368-8689 Web: http://www.wvbauer.com ________________________________________ From: r-help-boun...@r-project.org [r-help-boun...@r-project.org] On Behalf Of Holger Steinmetz [holger.steinm...@web.de] Sent: Wednesday, June 01, 2011 10:10 AM To: r-help@r-project.org Subject: Re: [R] Metafor: Differences between two categories of a moderator Hi Wolfgang that's good news. One further small follow-up question: When I conduct multiple comparisons via the relevel-command: should I adjust the p-value? Thanks in advance, Holger -- View this message in context: http://r.789695.n4.nabble.com/Metafor-Differences-between-two-categories-of-a-moderator-tp3562778p3565210.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
