[R-meta] Threshold values for Cook's Distances and DFBETAS
Hello Wolfgang, hello Michael, thanks for taking the time to answer my question. This was very helpful. Best, Theresa
Von: Michael Dewey <lists at dewey.myzen.co.uk>
Gesendet: Freitag, 30. September 2022 11:07:31 An: Th?lking, Theresa; r-sig-meta-analysis at r-project.org Betreff: Re: [R-meta] Threshold values for Cook's Distances and DFBETAS Dear Theresa My feeling is that these diagnostics are better seen as identifying values which may benefit from further investigation. If I was concerned that they were unduly influential in the model I might try fitting leave-one-out models but since those models are essentially data-driven they are also only useful in an exploratory sense. So, even if there is a formula I would be sceptical about its value in answering the scientific question. Michael On 29/09/2022 21:35, Th?lking, Theresa wrote: > Hello everybody, > > > I am trying to apply the outlier and influence diagnostics as described by Viechtbauer and Cheung (2010) on a meta-analysis I conducted, using a four-level random-effects model with 528 included effect sizes. I have calculated the Cook's Distances and DFBETAS in R, using the functions for model diagnostics for rma.mv objects as described here: https://wviechtb.github.io/metafor/reference/influence.rma.mv.html > > > However, I don't know how to decide about which studies are influential based on these values. I read the paper by Viechtbauer and Cheung, but I don't quite understand it. Is there some kind of formula to determine the threshold values of CD and DFBETAS for a meta-analytic model with k outcomes? Thanks in advance for your help. > > > Best, > > Theresa > > [[alternative HTML version deleted]] > > _______________________________________________ > R-sig-meta-analysis mailing list @ R-sig-meta-analysis at r-project.org > To manage your subscription to this mailing list, go to: > https://stat.ethz.ch/mailman/listinfo/r-sig-meta-analysis > -- Michael http://www.dewey.myzen.co.uk/home.html