addpoly is generic. It can be used to add polygons to a forest plot, for example, to indicate summary estimates for all or subgroups of studies and to indicate fitted/predicted values based on models involving moderators.addpoly(x, ...)"rma" or the values at which polygons should be drawn. See x is a fitted model coming from the rma.uni, rma.mh, rma.peto, or 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 (often at the bottom), showing the summary estimate with corresponding confidence interval based on the fitted model.
Alternatively, object x can be a vector with values at which one or more polygons should be drawn. The corresponding method is then addpoly.default.addpoly.rma, addpoly.default, forest.rma, forest.default