The metafor Package

By default, the forest() function places the annotations (giving the study-specific estimates and corresponding confidence interval bounds) to the right of the actual forest plot. See here for an example. Sometimes, we might prefer to show those annotations in a different position. This can be done with the textpos argument, which takes as input a vector of length 2 to specify the placement of the study labels and the annotations. The plot below illustrates the use of this argument.

library(metafor)
 
### copy BCG vaccine meta-analysis data into 'dat'
dat <- dat.bcg
 
### calculate log risk ratios and corresponding sampling variances (and use
### the 'slab' argument to store study labels as part of the data frame)
dat <- escalc(measure="RR", ai=tpos, bi=tneg, ci=cpos, di=cneg, data=dat,
              slab=paste(author, year, sep=", "))
 
### fit random-effects model
res <- rma(yi, vi, data=dat)
 
### forest plot with extra annotations
forest(res, atransf=exp, at=log(c(0.05, 0.25, 1, 4)), xlim=c(-20,2),
     ilab=cbind(tpos, tneg, cpos, cneg), ilab.xpos=c(-13.5,-12,-10,-8.5),
     cex=0.75, header="Author(s) and Year", mlab="", textpos=c(-20,-3.5), shade=TRUE)
op <- par(cex=0.75, font=2)
text(c(-13.5,-12,-10,-8.5), res$k+2, c("TB+", "TB-", "TB+", "TB-"))
text(c(-12.75,-9.25),       res$k+3, c("Vaccinated", "Control"))
par(op)
 
### add text with Q-value, dfs, p-value, and I^2 statistic
text(-20, -1, pos=4, cex=0.75, bquote(paste(
     "RE Model (Q = ", .(fmtx(res$QE, digits=2)),
     ", df = ", .(res$k - res$p), ", ",
     .(fmtp(res$QEp, digits=3, pname="p", add0=TRUE, sep=TRUE, equal=TRUE)), "; ",
     I^2, " = ", .(fmtx(res$I2, digits=1)), "%)")))