**UPDATE:** Please see the following post for an all-in-one solution: RePROCESS Model 1

This post was was inspired by Nicholas Michalak’s Novum R-ganum blog posts on reproducing Hayes’ PROCESS Model 1 in *R*. He has two posts where he presents the *R* code for examining a continuous × continuous moderation and a dichotomous × continuous moderation.

However, a quick Google search suggests a paucity of information for conducting moderation analyses using a multicategorical moderating variables.

Therefore, this post will outline how to run the PROCESS Model 1 with a multicategorical moderator (*M*) in *R*. We will examine how to code the *M* variable, simulate some data, run the PROCESS analyses in both *SPSS* and *R,* and compare the results from both software packages.

Continue reading “Moderation with a multicategorical moderating variable”