### Table of Contents

## Radial (Galbraith) Plot

### Description

The radial plot (also called Galbraith plot) was introduced by Rex Galbraith (1988a, 1988b, 1994) and can be useful in the meta-analytic context to examine the data for heterogeneity. For an equal-effects model, the plot shows the inverse of the standard errors on the horizontal axis against the observed effect sizes or outcomes standardized by their corresponding standard errors on the vertical axis. On the right hand side of the plot, an arc is drawn corresponding to the observed effect sizes or outcomes. A line projected from (0,0) through a particular point within the plot onto this arc indicates the value of the observed effect size or outcome for that point. An example of such a plot is shown below

### Plot

### Code

library(metafor) ### fit equal-effects model res <- rma(yi, vi, data=dat.hackshaw1998, method="EE") ### adjust margins so the space is better used par(mar=c(5,4,0,3)) ### draw radial plot radial(res)

### References

Galbraith, R. F. (1988a). Graphical display of estimates having differing standard errors. *Technometrics, 30*(3), 271โ281.

Galbraith, R. F. (1988b). A note on graphical presentation of estimated odds ratios from several clinical trials. *Statistics in Medicine, 7*(8), 889โ894.

Galbraith, R. F. (1994). Some applications of radial plots. *Journal of the American Statistical Association, 89*(428), 1232โ1242.