Add prediction interval forest plot (package "meta")
At 12:39 07/06/2013, Bernd Wei? wrote:
Am 07.06.2013 13:17, schrieb Michael Dewey:
At 19:34 06/06/2013, Bernd Weiss wrote:
Dear all, I am struggling to add a prediction interval to a forest plot that was created with forest.meta(), package "meta". I checked the source of forest.meta() and realized that it is heavily relying on grid. I am lacking any experience with grid graphics. So, I am having difficulties to find out where the random effects estimate is actually plotted in order to add prediction intervals.
I appreciate this is not a direct answer to your question but the equivalent function in metafor (available from CRAN) does this and it might be easier to use that.
Thanks, Michael! Yes, I vaguely remember that the metafor package can calculate the PIs but most of our analyses rely on the meta package. On the other hand, this might be a good reason to finally switch to metafor. You probably refer to the function addpoly() which can be used for that. I will check it out.
I was thinking of the addcred parameter to forest.rma.uni in fact, although you could roll your own.
Again, thanks for your help, Bernd
Michael Dewey info at aghmed.fsnet.co.uk http://www.aghmed.fsnet.co.uk/home.html