Aaron Fisher posted on Thursday, December 03, 2009 - 6:56 pm
I have a GMM with 4 latent classes. When I estimate the model using this syntax:
classes = c(4); analysis: type = mixture; starts = 25 2; model: %overall% i s | d2@email@example.com@firstname.lastname@example.org; c#1 on d1; c#2 on d1; c#3 on d1;
%c#2% i s; %c#3% i s; %c#4% i s;
I discover that there are negative error variances for the slopes for classes 2 and 3. I would like to fix these to zero however, every time I try to do so the classes change order and I am fixing the variances for the wrong class. I have seen advice on this message board re: using starting values to get a particular order for the latent classes. Nevertheless, I have been unable to effectively manipulate the order of the classes.
Any help you can give will be greatly appreciated.