Parallel process count and continuous... PreviousNext
Mplus Discussion > Growth Modeling of Longitudinal Data >
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 Jacqueline Homel posted on Tuesday, December 11, 2012 - 4:01 pm
I am trying to estimate a parallel process latent growth model with five waves of data from adolescence to early adulthood. The outcomes are depression (continuous) and number of conduct disorder symptoms (count, maximum 4). The sample size is 662. My input is:

usevar are DEP1 DEP2 DEP3 DEP4 DEP5 cdc41 cdc42 cdc43 cdc44 cdc45 ;

count are cdc41 cdc42 cdc43 cdc44 cdc45 ;

Analysis:
estimator = mlr ;
Algorithm = integration ;
Integration =5 ;
starts 40 2 ;
stiterations = 20 ;

MODEL:
icond scond qcond | cdc41@0 cdc42@1 cdc43@2 cdc44@3 cdc45@4 ;
idep sdep qdep | dep1@0 dep2@1 dep3@2 dep4@3 dep5@4 ;

However, I receive the following error messages:

THE ESTIMATED COVARIANCE MATRIX COULD NOT BE INVERTED. COMPUTATION COULD NOT BE COMPLETED IN ITERATION 227. CHANGE YOUR MODEL AND/OR STARTING VALUES.

THE MODEL ESTIMATION DID NOT TERMINATE NORMALLY. ESTIMATES CANNOT BE TRUSTED.

Is there a special way to model continuous and non-continuous growth curves together? Any advice would be much appreciated.
 Linda K. Muthen posted on Tuesday, December 11, 2012 - 5:31 pm
As a first step, I would try each growth model separately.

I would not use INTEGRATION = 5. I would instead use INTEGRATION = MONTECARLO (5000).
 Jacqueline Homel posted on Tuesday, December 11, 2012 - 10:00 pm
Thanks - I have already tried each growth model separately, and they run fine and make sense.

I tried your montecarlo suggestion, but still fail to get estimates, and the following error message:

THE MODEL ESTIMATION DID NOT TERMINATE NORMALLY DUE TO A NON-ZERO DERIVATIVE OF THE OBSERVED-DATA LOGLIKELIHOOD.

THE MCONVERGENCE CRITERION OF THE EM ALGORITHM IS NOT FULFILLED. CHECK YOUR STARTING VALUES OR INCREASE THE NUMBER OF MITERATIONS. ESTIMATES CANNOT BE TRUSTED. THE LOGLIKELIHOOD DERIVATIVE FOR PARAMETER 17 IS -0.66093711D+01.

Is it possible that the data are simply not suitable for this type of model?
 Linda K. Muthen posted on Wednesday, December 12, 2012 - 8:48 am
Please send the output and your license number to support@statmodel.com.
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