# Doing Meta Analysis in R

*A Hands-on Guide*

*Friedrich-Alexander-University Erlangen-Nuremberg & Vrije Universiteit Amsterdam*

# Chapter 1 About this Guide

This guide shows you how to conduct Meta-Analyses in R from scratch. The focus of this guide is primarily on clinical outcome research in psychology. It is designed for staff and collaborators of the **PROTECT Lab**, which is headed by **Dr. David D. Ebert**.

**The guide will show you how to:**

- Get
**R**and**RStudio**set for your Meta-Analysis - Get your data into R
**Prepare your data**for the meta-analysis- Perform
**fixed-effect**and**random-effects**meta-analysis using the`meta`

and`metafor`

packages - Analyse the
**heterogeneity**of your results - Tackle heterogeneity using
**subgroup analyses**and**meta-regression** - Check if
**selective outcome reporting (publication bias)**is a present in your data - Control for selective outcome reporting and publication bias
- Analyse the
**risk of bias**in your data - Do advanced types of meta-analyses, such as
**network analyses**or- meta-analyses with
**more than one outcome**

**What this guide will not cover**

Although this guide will provide some information on the statistics behind meta-analysis, it will not give you an **in-depth introduction** into how meta-analyses are calculated statistically.

It is also beyond the scope of this guide to advise in detail which meta-analytical strategy is suited best in which contexts, and on how the search, study inclusion and reporting of meta-analyses should be conducted. The *Cochrane Handbook for Systematic Reviews of Interventions*, however, should be a great source to find more information on these topics.

**Generally, there a two other sources to recommended when conducting Meta-Analyses:**

- If you’re looking for a easily digestable, hands-on introduction on how Meta-Analyses are conducted, we can recommend
**Pim Cuijpers’ online courses on Meta-Analysis**. The courses are freely available on YouTube. To have a look, click here. - If you’re interested in more details on how to conduct Meta-Analyses in R, you can either have a look at Wolfgang Viechtbauer’s page for the
`metafor`

package (Link). Or you can consult a book on the`meta`

package which was recently published (Schwarzer, Carpenter, and Rücker 2015).

**How to get the R code for this guide**

All code behind this book is available online on **GitHub**. We have created a website containing a **download link** for all codes, and a **quick guide** on how to get the code running on your computer. The site can be found here.

**How to cite this guide**

Harrer, M. & Ebert, D. D. (2018). Doing Meta-Analysis in R: A practical Guide. *PROTECT Lab Friedrich-Alexander University Erlangen-Nuremberg*. https://bookdown.org/MathiasHarrer/Doing_Meta_Analysis_in_R/

**To get started, proceed to the next chapter!**

### References

Schwarzer, Guido, James R Carpenter, and Gerta Rücker. 2015. *Meta-Analysis with R*. Springer.