TECH11 - Replication of H0 Loglikelih... PreviousNext
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 Jen posted on Friday, December 20, 2013 - 1:14 pm
Hello,

I am having issues replicating the H0 loglikelihood value for the K-1 solution in the TECH11 output when comparing 5- and 6-class solutions in a LCA.

I have read "Using Mplus TECH11 and TECH14 to test the number of latent classes" and generally had good luck with the described method.

I have no problems replicating the loglikelihood values for either the c(5) or c(6) solutions themselves (with a modest number of starts, such as STARTS = 400 80), yet no matter how high I put the K-1STARTS for c(6) (I have gone up to 5000 1000), I cannot replicate the c(5) loglikelihood value in the TECH11 output (the loglikelihood for the c(5) = -5974.33, but in TECH11 it consistently = -5989.43).

Should I worry about this, and is there anything else I might try?

Thank you!
 Bengt O. Muthen posted on Friday, December 20, 2013 - 2:24 pm
I assume this is a regular "exploratory" LCA so that the first class - which is dropped when doing the k-1 class model in the k-class run - doesn't have any parameter restrictions.

You can try stscale=10 or 20 or 30.

Mplus drops the first class of the 6-th class solution this gives the starting values for the 5-th class solution. If there is a some kind of perfect indicator in the 6-class solution that is not there for the 5-class solution this can happen.

If you can match the classes between the 5-class and the 6-class solution, put the extra class as class one (you can do that by using stvalues or different optseed for the 6 class solution) so that the extra class come up as class 1 in the 6-class solution.
 Jen posted on Monday, January 06, 2014 - 8:50 pm
Thank you! stscale fixed the problem immediately, with a much lower k-1starts.
 Pia H. posted on Friday, August 11, 2017 - 6:23 am
Hello,

I am running a factor mixture analysis and am facing a similar problem as described above. This is my input for a 3 class model:

ANALYSIS:
TYPE = MIXTURE;
STARTS = 8000 2000;
ALGORITHM = INTEGRATION;
PROCESSORS = 32(STARTS);


MODEL:

%OVERALL%
f1 BY PCL1 PCL2 PCL3
PCL4 PCL5 PCL6;
f2 BY PCL7 PCL8 PCL9
PCL10 PCL11 PCL12;

[PCL1$1-PCL12$2](1-24);

%c#1%
f1-f2;
f1 with f2;
[f1-f2@0];


%c#2%
f1-f2;
f1 with f2;
[f1-f2*];


%c#3%
f1-f2;
f1 with f2;
[f1-f2*];

The loglikelihood is replicated > 10 times. However, the loglikelihood I get for this model slightly differs from the k-1 loglikelihood obtained with TECH11 in the next step (not only for 3 vs. 2 classes, but also for 4 vs. 3 and 2 vs.1). The differences are quite small (i.e. -3409.149 vs. -3409.151). Are these differences negligible?

Thank you!
 Bengt O. Muthen posted on Friday, August 11, 2017 - 10:13 am
Yes, with numerical integration involved I would say this difference is negligible.
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