The metafor Package

Happy New Year! Hope this one will be at least marginally less crazy than the previous ones ...

I was recently asked whether I would add the feature to show multiple confidence intervals for each of the studies in a forest plot (e.g., by using lines with varying thickness) to the metafor package. Turns out that one can already do this without too much difficulty using the existing tools, simply by superimposing two forest plots on top of each other. This is illustrated here.

I also wanted to see to what extent one can reproduce forest plots created by different software or using the aesthetics of certain journals. I started with the recreation of a forest plot that was obtained using RevMan, the software provided by the Cochrane Collaboration for conducting and authoring Cochrane reviews. You can find the figure and corresponding code for this here. Then I recreated a forest plot that was obtained from an article in the British Medical Journal. The resulting figure and code can be found here.

Although it takes a bit of effort to recreate these figures (especially if one wants to make them look almost identical to the originals), it shows that one can essentially recreate any forest plot using the various forest() functions from metafor and then some additional functions like text(), points(), and so on, which give you full control over how things are drawn and the information included in the figure.