Below you can find some suggestions and tips on getting started with the metafor package and how to obtain help if you get stuck or have questions about the package.
A good starting place for those interested in using the metafor package is the following paper:
Viechtbauer, W. (2010). Conducting meta-analyses in R with the metafor package. Journal of Statistical Software, 36(3), 1–48.
You can download the paper here: https://doi.org/10.18637/jss.v036.i03. If the package is installed, you should also be able to open the paper with
The purpose of the paper is to provide a general overview of the metafor package and its capabilities (as of version 1.4-0). Not all of the functions and options are described (since a lot of additional functionality has been added to the package since the paper was published), but it should provide a useful introduction to the package.
At the beginning of 2022, I held an open workshop on meta-analysis with R (as part of the Evidence Synthesis & Meta-Analysis in R Conference). More details about the workshop can be found here. The materials from the workshop can be found here. The scripts from this workshop are heavily annotated and provide a pretty structured and thorough introduction to the use of the metafor package.
If you are learning meta-analysis itself, you might be in the process of reading one or multiple books on meta-analysis. I have created R code to reproduce the examples and illustrations from various books on meta-analysis, which you can find here. Using these scripts while reading the contents of these books will also provide you with a pretty thorough introduction not only to meta-analysis itself, but also the use of R and the metafor package.
The official reference manual (as a pdf) for the package can be found on CRAN. The manual describes all of the functions in the package together with their arguments and options. In R, you can also start browsing the documentation by typing
help(metafor) (after loading the package with
You can also read the entire documentation online at https://wviechtb.github.io/metafor/ (where it is nicely formatted, equations are shown correctly, and the output from all examples is provided).
A diagram showing the various functions in the metafor package (and how they are related to each other) can be found here. If the package is installed, you should also be able to open this diagram directly from R with the command
If you need help with using the package, please do not send emails to me directly. I get multiple emails per day with at times lengthy and complicated questions about meta-analysis in general and the metafor package in particular and I just cannot answer them all. Instead, please post your question to the R-sig-meta-analysis mailing list, one of the R Project mailing lists specifically dedicated to discussing the use of R for conducting meta-analyses. That way, you have a larger audience that may be able to provide answers and other users can benefit from the information and answers provided there. Before participating in any of the R-related mailing lists, please read the posting guide first. Also, here are some links to:
Questions around the metafor package have also been addressed on the R-help and the R-sig-mixed-models mailing lists. Here are links to:
Stack Exchange is a network of question and answer websites on a wide variety of topics. Two of the websites may be of particular interest to users of the metafor package, as questions about the package have already been raised and answered there: Cross Validated is a website for people interested in statistics, machine learning, data analysis, data mining, and data visualization and Stack Overflow is a website for professional and enthusiast programmers. You can search these sites directly for questions that may be related to the metafor package:
Again, the advantage of posting your question to these websites is that you have a larger audience that may be able to provide assistance and the answers provided will be available to other users in the future.