addpoly function can be used to add polygons, sometimes called ‘diamonds’, to a forest plot, for example to indicate summary estimates for subgroups of studies or to indicate fitted/predicted values based on models involving moderators.
either an object of class
Currently, methods exist for two types of situations.
In the first case, object
x is a fitted model coming from the
rma.glmm functions. The model must either be a fixed- or random-effects model, that is, the model should not contain any moderators. The corresponding method is called
addpoly.rma. It can be used to add a polygon to an existing forest plot (usually at the bottom), showing the summary estimate (with its confidence interval) based on the fitted model.
x can be a vector with values at which one or more polygons should be drawn. The corresponding method is then
Viechtbauer, W. (2010). Conducting meta-analyses in R with the metafor package. Journal of Statistical Software, 36(3), 1--48. https://doi.org/10.18637/jss.v036.i03