Multiple mediation analysis PreviousNext
Mplus Discussion > Growth Modeling of Longitudinal Data >
 Patrick A. Palmieri posted on Thursday, May 04, 2006 - 8:54 am

I don't have a lot of MPlus experience. I am trying to modify an example program from the manual to run a multiple mediation analysis and could use some assistance.

I have time 1 measurements for an independent variable, two mediator variables, and two outcomes. I have time 2 measurements of the two mediators. I have time 3 measurements of the two outcomes. I would like to test the total indirect effect of both time 2 mediators on time 3 outcomes, as well as each of their specific indirect effects after accounting for the other mediator, and I also would like to control for time 1 levels of both mediators and both outcomes.

Below is my input file. My questions are:
1. What modifications to the model paragraph would control for time 1 measurement of the mediators and the outcomes?
2. Does the rest of the syntax look correct for the intended analysis?
Patrick Palmieri

file is C:\mplus\mediation.dat;
format is free;
type is individual;
nobservations are 625;
names are iv t1med1 t1med2 t1dv1 t1dv2 t2med1 t2med2 t3dv1 t3dv2;
usevariables iv t1med1 t1med2 t1dv1 t1dv2 t2med1 t2med2 t3dv1 t3dv2;
missing are all (-9);
type = general missing H1;
estimator = ML;
iterations = 50000;
bootstrap = 5000;
t2med1 on iv;
t2med2 on iv;
t3dv1 on t2med1 t2med2 iv;
t3dv2 on t2med1 t2med2 iv;
t2med1 with t2med2;
t3dv1 with t3dv2;

model indirect:
t3dv1 IND t2med1 iv;
t3dv1 IND t2med2 iv;
t3dv2 IND t2med1 iv;
t3dv2 IND t2med2 iv;

sampstat standardized cinterval(bcbootstrap);
 Linda K. Muthen posted on Thursday, May 04, 2006 - 2:32 pm
I think you want to regress t1dv1 t1dv2 on
t1med1 t1med2. I don't see that in the MODEL command. That would be:

t1dv1 t1dv2 ON t1med1 t1med2;

Otherwise, I can't see any problems. The best way to see if you have set the input up correctly is to run the analysis and see if you get what you want.
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