Analyzing data of a Multilab replication project with individual participant data meta-analysis: A tutorial

Multilab replication projects such as Registered Replication Reports (RRR) and Many Labs projects are used to replicate an effect in different tabs. Data of these projects are usually analyzed using conventional meta-analysis methods. This is certainly not the best approach because it does not make optimal use of the available data as a summary rather than participant data are analyzed. I propose to analyze data of multilab replication projects with individual participant data (IPD) meta-analysis where the participant data are analyzed directly. The prominent advantages of IPD meta-analysis are that it generally has larger statistical power to detect moderator effects and allows drawing conclusions at the participant and lab level. However, a disadvantage is that IPD meta-analysis is more complex than conventional meta-analysis. In this tutorial, I illustrate IPD meta-analysis using the RRR by McCarthy and colleagues, and 1 provide R code and recommendations to facilitate researchers to apply these methods.