I have decided to write an R version of the PROCESS macro for mediation, moderation, and conditional process analysis, which is called RePROCESS.
I will regularly update the package as I add more models and post updates on this blog.
Unlike the SPSS macro, it generates the plots for you, and runs the analyses run at least four times faster! However, I’m not sure how computation time compares to the SAS version.
The development version of the package has now been released and allows you to run Model 1, which is for a single predictor and moderator variable.