Simulation and Growth Modeling
Message/Author
 Anonymous posted on Thursday, October 06, 2005 - 1:28 pm
I'm trying to simulate a growth model for a grant. I have the model developed the way that I want to determine power. However, I am unable to control the means and variances for the growth factors. For example, I'm trying to constrain these factors of means (2.50 1.75 1.50 .75).

I've tried the following syntax:
[p1@2.50]; p1*10.00;

However, when I put the covariates into the model, these means go away and they are inflated. Without keeping the means in place, I'm unable to be confident in the simulation. How should I proceed with this issue? Any advice you can offer would be great. Thank you very much.
 Linda K. Muthen posted on Saturday, October 08, 2005 - 2:02 pm
When you have covariates in the model, the values in square brackets are no longer means, they are intercepts. You need to take that into account. Likewise, when covariates are added to the model, residual variances and not variances are estimated.
 QianLi Xue posted on Tuesday, August 20, 2013 - 11:12 am
In the simulation file named "mcex6.11.inp" for your EXAMPLE 6.11: PIECEWISE GROWTH MODEL FOR A CONTINUOUS OUTCOME, I did not find the specification of the variance and covariance parameters for random growth factors: i,s1,s2.What are your default values for them? Thanks!
 Linda K. Muthen posted on Tuesday, August 20, 2013 - 1:24 pm
The variances are shown as

i*1; s1-s2*.2;

The covariance is not shown so the value zero is used. Any parameter for which a population value is not shown is given the value zero.
 JIKIM posted on Friday, April 13, 2018 - 3:41 am
Hi, I am struggling to get an outcome for my research model.

After I read your article "Auxiliary Variables in Mixture Modeling: Three-step Approaches Using Mplus", I doing a similar practice study in GMM context.

So the point is, I did simulation study to compare the performance of mixture approaches(LTB, 3STEP(BCH, ML), one-step.

When I try to take LTB approach(DCON), Mplus does not show me any results nor any warning. It's just that the black screen stops only few seconds after it starts to work
Isn't it that the syntax for LTB approach is the same as BCH?
Do I need to change anything?
 Bengt O. Muthen posted on Friday, April 13, 2018 - 4:18 pm
We need to see your output/input and data for the problematic run - send to Support along with your license number.