I have a question about centering with random slopes in MSEM. I am using version 8.0.
I have a 1-1-1 multilevel path analysis (with a level 2 moderator on the b-path). Here is a simplified version of my syntax:
USEVARIABLES ARE x m y w; Centering is groupmean(x); Centering is grandmean(w); Cluster=id; Within=x; Between=w;
Analysis: Type = TWOLEVEL Random; Estimator = mlr;
%Within% sa|m on x; sb|y on m; sc|y on x;
%Between% sb on w; y on w;
sa with sb sc m y; sb with sc m y; sc with m y; m with y;
As you can see, I used observed centering to ensure that my x variable is group mean centered, because when using random slopes in Mplus, "the random slope precludes the latent variable decomposition of X when using ML estimation". However, in the above syntax, would m (my mediator variable) be latent mean centered (i.e., the within- and between-person variance of these variables are latently partialed)? Or should I also be using observed centering for variable m to ensure that the within- and between-person variance of that variable is properly separated?
Please let me know which set-up is correct. How does Mplus treat the centering of the mediator variable in each of these two scenarios?