yk leung posted on Wednesday, November 01, 2017 - 3:19 am
I am trying to replicate the results I obtained from model 4 (simple mediation) of the SPSS macro PROCESS. But the results, seems to be very different. Specifically, the indirect effect estimated by PROCESS is highly significant while it is not in Mplus.
I was wondering why would this be the case and more importantly how might I obtain the same result as in PROCESS? Many thanks!!
Code in Mplus: Mplus code for the model: ! Predictor variable - X ! Mediator variable(s) – M ! Moderator variable(s) - none ! Outcome variable - Y ! Control variable - C
USEVARIABLES = X C M Y;
MISSING = ALL(-999);
BOOTSTRAP = 1000;
! In model statement name each path using parentheses MODEL: Y ON X C (cdash); Y ON M (b1); M ON X C (a1);
! Use model constraint to calculate indirect and total effect
MODEL CONSTRAINT: NEW(a1b1 TOTAL); a1b1 = a1*b1; ! Indirect effect of X on Y via M TOTAL = a1*b1 + cdash; ! Total effect of X on Y