The `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.

addpoly(x, ...)

## Arguments

x |
either an object of class `"rma"` or the values at which polygons should be drawn. See ‘Details’. |

... |
other arguments. |

## Details

Currently, methods exist for two types of situations.

In the first case, object `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 (usually at the bottom), showing the summary estimate (with its 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`

.

## Author

Wolfgang Viechtbauer wvb@metafor-project.org http://www.metafor-project.org

## References

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

## See also