I am estimating a longitudinal GMM, where i am interested first, in a number of trajectories in children's executive function (based on their rate of change), and second, how children's rate of change in executive function in elementary school is associated with different achievement outcomes in middle school (e.g., distal outcomes).
I am wondering if it is possible to include continuous moderators in these analyses? something like creating an interaction variable, moderator X executive function, or should it be moderator X class?
I have only seen discussions about GMM models with the distal outcomes and covariates, but nothing about moderators. Should i treat my moderators as covariates then?