I have a question concerning the inclusion of control variables into my research. I have data from an experimental, randomly distributed social protection program. I want to test whether a moderating variable influences the relationship between treatment and outcome. Also, I want to test for other confounds. However, the experimental design should eliminate the effect of all third variables, right? But in this case, I want to focus on the moderating variable, not the treatment itself. Is it ok to include control variables or is it rather a mediated moderation?