Factor mixture model for 2 classes wi... PreviousNext
Mplus Discussion > Latent Variable Mixture Modeling >
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 Arpana posted on Thursday, August 10, 2006 - 1:55 pm
Dear Dr. Muthen, I am trying to fit a FMA with 2 latent classes (where one is a zero class) and each class has 2 factors:
MODEL: %overall%
drug1 by sed* cann@1 coke tranq opit amphe hall inhal@0 ; drug2 by sed@0 cann@1 coke tranq opit amphe hall inhal;
drug1 with drug2 ;drug1*1; drug2*1;[drug1@0] ;[drug2@0] ;
%c#1%
[cann$1-inhal$1@15] ;
drug1 by cann-inhal@0 ;
drug2 by cann-inhal@0 ;
drug1@0 ; drug2@0 ;
drug1 with drug2@0 ;
%c#2%
[cann$1-inhal$1] ;
drug1 by sed cann@1 coke tranq opit amphe hall inhal@0 ;
drug2 by sed@0 cann@1 coke tranq opit amphe hall inhal ;
drug1 with drug2 ;drug1 ; drug2 ;
I get several error messages related to model identification. Is there a parameter/s I should constrain to identify this model?
 Bengt O. Muthen posted on Friday, August 11, 2006 - 12:41 am
I can't see a problem off hand, so please send your input, output, data and license number to support@statmodel.com. Be sure to include Tech1 in the output.
 Arpana posted on Monday, August 14, 2006 - 12:11 pm
Dear Dr. Muthen,

I fixed the factor variances in c#2 to 1.0 and that seemed to do it. Thanks!
 Bengt O. Muthen posted on Monday, August 14, 2006 - 12:46 pm
But you already have one loading fixed at 1 for each factor, which identifies the factor variances. Seems like there is something else going on. You have a regular factor model in class 2 with factor means zero so that should be fine. Look at Tech1 to see that you get the parameters freed that you expect.
 Arpana posted on Thursday, August 24, 2006 - 12:37 pm
Dear Dr. Muthen,
I have emailed the code and data to the above email address and look forward to your suggestions.
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