> -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] > On Behalf Of Antonello Preti > Sent: Monday, November 24, 2014 00:35 > To: r-help@r-project.org > Subject: [R] arcsine transformation with metafor > > # I'm trying to adapt to my own data the double arcsine transformation > according to Miller (1978) as described in the metafor site > # I've understood all passages (I think) > # I'm able to build a forest plot with the correct data > # I would like to build a funnel plot and a radial plot > # However, the rule that is helpful to build a forest plot does not work > for the radial or the funnel plot > # When I use the results of the fixed (or random) effects model, as > expected, the estimates are wrong (about two times the correct estimates) > # How can the radial and funnel plot be built for the double arcsine > transformation? > > # Thank you in advance, Antonello > > # Here the code I've used > > library(metafor) > > # The data used by Miller (1978) to illustrate the transformation and its > inversion can be re-created with: > > dat <- data.frame(xi=c(3, 6, 10, 1), ni=c(11, 17, 21, 6)) > dat$pi <- with(dat, xi/ni) > dat <- escalc(measure="PFT", xi=xi, ni=ni, data=dat)
[SNIP] > res <- rma(yi, vi, method="FE", data=dat) [SNIP] > ### However, this is wrong > > radial(res) > funnel(res) They are not wrong. The double arcsine transformed values are used for the plotting, not the raw proportions. In particular, the plots are based on 'yi' in: > dat xi ni pi yi vi 1 3 11 0.2727273 0.5695 0.0217 2 6 17 0.3529412 0.6444 0.0143 3 10 21 0.4761905 0.7626 0.0116 4 1 6 0.1666667 0.4758 0.0385 Best, Wolfgang ______________________________________________ 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.
