Elisabeth Su posted on Thursday, September 24, 2015 - 7:58 am
I'm a new learner of Mplus. I'm calculating a GMM with 3 classes and one covariate. However, I get the following warning, and one class has 0 class counts:
One or more parameters were fixed to avoid singularity of the information matrix. The singularity is most likely because the model is not identified, or because of empty cells in the joint distribution of the categorical variables in the model. The following parameters were fixed: 5 6 7 8 18 20
I tried to run a 3-class unconditional model and a 2-class GMM with one covariate, and the results were fine.
My question is what does the warning means and how to deal with it? I would be very thankful for your help!