

Loglikelihood for H0 in VLMR and BLRT... 

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George Y posted on Sunday, October 06, 2013  7:41 pm



Hi, I am running growth mixture models and am trying to interpret the output from the VuongLoMendellRubin likelihood ratio test and bootstapped parametric likelihood ratio tests. When running simple latent class growth models (i.e., with growth parameter variances fixed) then I can see that the loglikelihood for H0 (i.e., K1 classes) is the same as what is estimated if I was to run the K1 class model itself. However, if I start freeing up some of the variances (e.g., say I free up two intercept variances) then I am unsure of what model this H0 model is. Is it the same as the K1 model also with two intercept variances freed? I cannot seem to identify what this H0 model is that it is comparing to. I assumed that I should be able to estimate this H0 model itself. For example, if I was comparing the K=3 class model with 2 intercept variances free, then I thought that the K1 H0 model in the VLMR and BLRT tests would have the same loglikelhood as if I just estimated a K=2 class model with the same 2 intercept variances free. But the loglikelihoods are not the same when I run it myself. I also quickly tried to increase the starts for the VLMR and BLRT tests thinking that perhaps it was a local solution but not sure whether that was the right thinking or not. I didn't get any error saying the loglikelihood was not replicated. Any guidance here would be much appreciated. Thanks for your time. 


We drop the first class for the k1 model. 

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