Latent curve model on the basis of cl... PreviousNext
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 Veronica Cole posted on Tuesday, April 29, 2014 - 4:45 pm
Drs. Muthen,

My question concerns the manual 3-step estimation. Is it possible to put any model one desires into that third step, even a latent curve?

Specifically, Iíve estimated a latent class model on the basis of some indicators (say, X1-X10). Then I want to see if the resultant latent classes are linked to different latent curves based on different variables (say, Z1-Z5).

I have tried to run this in a way similar to Input File 16 in Web Note 15. So for instance, given that modal class is treated as a categorical variable N, the overall statement and the first classí model look like this:

%OVERALL%
I S | Z1@0 Z2@1 Z3@2 Z4@3 Z5@4;
S@0;

%C#1%
[N#1@3.789];
[N#2@-.546];
[N#3@1.345];
[I] (i1);
[S] (s1);

...etc.

I set the overall within-class variance of the slope to zero to ease estimation burden. The model estimated just fine, and I got results that make sense. My question, though: is this a tenable way of doing things? The classes do appear to change slightly, but I will be checking allocation consistency in the way outlined in the Web Note.

Thank you very much!
 Linda K. Muthen posted on Wednesday, April 30, 2014 - 5:10 pm
This is fine.
 Veronica Cole posted on Wednesday, May 14, 2014 - 11:51 am
Hi Dr. Muthen,

Thanks so much for your response. I have (what I hope is) a quick follow-up question.

When I ran the model as written above, allocation consistency from Step 1 to Step 3 wasn't great. However, I decided to try ALGORITHM = INTEGRATION and for some reason when I do that the class assignment barely changes at all from Step 1 to Step 3. It was pretty much perfect.

However, it doesn't seem to say anything about using ALGORITHM = INTEGRATION in Web Note 15, so I was concerned that this wasn't the right way to go about it.

Do you have any thoughts about why ALGORITHM = INTEGRATION changes things so much for the better? And, absent any red flags in the output, is it OK to proceed having used ALGORITHM = INTEGRATION?

Thank you very much!
 Veronica Cole posted on Wednesday, May 14, 2014 - 11:57 am
Hi Dr. Muthen,

Sorry, I just realized that I made an error here -- ALGORITHM = INTEGRATION obviously doesn't make things better, since STARTS = 0. My mistake.

I retract my most recent question. Thank you, and apologies.
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