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Mplus Discussion > Latent Variable Mixture Modeling >
 Gary Chan posted on Monday, June 02, 2014 - 4:53 pm
Hi all,

I am very new to LCA and I would be very grateful if I can get some directions on performing LCA.

I would like to run a LCA on 6 items and would like to constrain the item endorsement probabilities to be all 0 for one class. Can anyone please tell me or direct me to an example on how this can be done?

Thank you very much.
 Bengt O. Muthen posted on Monday, June 02, 2014 - 5:43 pm
See our UG ex 7.13 for examples of how you add constraints. You also want to read the reference we give there.
 Gary Chan posted on Wednesday, June 04, 2014 - 6:22 am
Thank you very much for your direction. I have set up a LCA and I got very strange results from the Lo-Mendell-Rubin test when I run a 4-class model with one class constraint to have 0 item endorsement probabilities for all items. The mean and standard deviation was not shown. The followings are the output.

Number of initial stage random starts 500
Number of final stage optimizations 250


H0 Loglikelihood Value -6232.377
2 Times the Loglikelihood Difference 35.222
Difference in the Number of Parameters 2
Mean *****************
Standard Deviation *****************
P-Value 1.0000

I also run a unconstraint model and I got an extremely large mean and standard deviation. Can you please advise why this happens? Any help would be greatly appreciated. Thank you very much.
 Linda K. Muthen posted on Wednesday, June 04, 2014 - 11:39 am
The asterisks mean the number was too large to fit in the space provided. Please send the output and your license number to
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