[R-meta] Question on funnel plot interpretation
Dear Gabriel Apart from Michael observation on data checking before analyses (which is always a good practice), I add one. The funnel plot is just a visual check of publication bias. So the observations based on the funnel plots are inevitably subjective - I mean you think that is "randomly scattering", while others might think not. In contrast, Egger's test is a more objective way to test the asymmetry of a funnel plot. Regarding how to do it, you can try to find them in the archives associated with this mailing list. Please be noted that whether none funnel plot and Egger's test can indicate publication bias directly. But it is common to assume the asymmetry of a funnel plot is caused by publication bias (or more precisely. small study effects), after accounting for heterogeneity. Best, Yefeng
From: R-sig-meta-analysis <r-sig-meta-analysis-bounces at r-project.org> on behalf of Michael Dewey via R-sig-meta-analysis <r-sig-meta-analysis at r-project.org>
Sent: Wednesday, 5 July 2023 19:31
To: R Special Interest Group for Meta-Analysis <r-sig-meta-analysis at r-project.org>
Cc: Michael Dewey <lists at dewey.myzen.co.uk>; Gabriel Cotlier <gabiklm01 at gmail.com>
Subject: Re: [R-meta] Question on funnel plot interpretation
Sent: Wednesday, 5 July 2023 19:31
To: R Special Interest Group for Meta-Analysis <r-sig-meta-analysis at r-project.org>
Cc: Michael Dewey <lists at dewey.myzen.co.uk>; Gabriel Cotlier <gabiklm01 at gmail.com>
Subject: Re: [R-meta] Question on funnel plot interpretation
Dear Gabriel My interpretation looking at your plots is that you have a very strange set of primary studies. If the x-axis is really the z transformation of r then some of the r are .999 and some 0.001 which seems worthy of investigation before looking further. Michael On 05/07/2023 09:14, Gabriel Cotlier via R-sig-meta-analysis wrote: > Hello all, > > I have produced a funnel plot on the basis of an rma.mv > <http://rma.mv>() objectapplied to all the data set together ( not > subsetting using moderators ) as follows: > > image.png > > > When looking at the figure I tried to think that maybe one of the > following two interpretations could be the correct one: > > a. There is a kind of random scattering of the effect sizes, therefore > no symmetry is found and thus publication bised is observed. > b. Given the randomness of the effect sizes distribution covering the > plot's space unevenly there is not a clear pattern that can indicate > publication bias is observed. > > Is any of this interpretation the correct one? > > Thanks a lot. > Kind regards, > Gabriel > > > #### CODE. ###### > funnel_all <- rma.mv <http://rma.mv>(yi, > vi, > random = ~ 1 | Article / Sample_ID, > data=dat) > png(file = "funnel.png", > width = 250, > height = 200, > res = 600, > units = "mm") > # par(mfrow = c(2, 1)) > > # full data > f1 <- funnel(funnel_all, > yaxis = "seinv", > level = c(90, 95, 99), > ylim = c(1, 20), > shade = c("white", "gray55", "gray75"), > refline = 0, > legend = TRUE) > mtext("A", side = 3, line = 0, adj = -0.13, cex = 2) > > dev.off() > > <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient> Virus-free.www.avg.com <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient> > > <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> > > _______________________________________________ > 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 _______________________________________________ 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