I will be testing a moderated mediation model with the approach described in Preacher, Rucker & Hayes (2007) in Figure 2 model 5 where W influences both indirect paths of the model.
For testing model 5, I have determined my Mplus code should be similar to the below code. However, I am unsure what (if any) modifications are necessary to test the nonlinear interaction involving the moderator? I am just beginning to use Mplus, but I have used other SEM software in the past.
Many Thanks, Jenny
ANALYSIS: BOOTSTRAP = 1000;
MODEL: M WITH MW; M ON X (a1) W XW (a3); Y ON M (b1) X W XW MW (b2);
MODEL CONSTRAINT: NEW(eff1 eff2 eff3); eff1=(a1+a3*.42)*(b1+b2*.42); eff2=(a1+a3*.53)*(b1+b2*.53); eff3=(a1+a3*.64)*(b1+b2*.64); OUTPUT: CINTERVAL(bcbootstrap);
...where .42, .53, and .64 are example values of W at which I want conditional indirect effects.