# Distinguishing between types of GMM

GMM is an abbreviation for

• Generalized Method of Moments
• Gaussian Mixture Models
• Growth Mixture Models

The second usage seems to be far more common on CV, but now that Lars Hansen has finally won a Nobel, would it be possible to somehow separate out the GMM questions? At the very least, it makes it hard to search.

• Maybe you can give a start by: i) creating a different tag from gmm, and ii) editing the excerpt and tag wiki in both tags to remove ambiguity. This would help with the future. Oct 22 '13 at 2:56
• For a more general version of this topic, see here Oct 22 '13 at 4:03
• I created a new tag for gmm. It also looks like there's an older generalized moments tag, but I can't add gmm as synonym since I don't have enough points on that tag. Oct 22 '13 at 7:51
• I also think that usage is rare, so perhaps the generalized moments tag should be retired. Oct 22 '13 at 7:56
• I've suggested gmm as synonym for generalized moments. I think both of the tags should be synonyms. Questions about GMM are rare, but so are question on econometrics. I wonder maybe generalized-moments tag came from economics.SE, when it was merged to crossvalidated.com? Oct 22 '13 at 11:25
• See here for previous discusion, Should the gmm tag be added? Oct 22 '13 at 15:08

Ah, not again!

Dimitriy, I did some work a few months ago of weeding out the generic gmm tag, and separating it into generalized-moments (generalized-method-of-moments was too long), gaussian-mixture for the classification/machine learning folks, and growth-mixture-model (which is what psychologists and education researchers think when they hear GMM). I think I kept the gmm wiki entry saying that the use of this tag is confusing and discouraged, in favor of these three specific ones, but since no questions were tagged gmm after my overhaul, it disappeared. Your... uhm... help in re-establishing gmm is... uhm... appreciated, but it would be much better if you folded the gmm description into generalized-moments.

Moderators: is there any way to protect a tag even if there are no entries for it?

• The tag can be banned forever, but it would be best if it is simply turned into a synonym. Oct 22 '13 at 16:08
• The problem with turning it into a synonym @gung is that the GMM acronym can't be differentiated between several different types of statistical analysis. I'd prefer not to (by default) choose one of those options as a synonym given the ambiguity. Oct 22 '13 at 17:41
• @gung, there has to be a disambiguation, something along the lines of "Please do not use gmm tag. Instead, use the generalized-moments for GMM in econometrics; gaussian-mixutre for GMM in machine learning and classification; and growth-mixture-model for GMM in psychology." Oct 22 '13 at 18:41
• I would suggest to clear the gmm tag and refer in the About section to the three other tags, as suggested by Stas. Also, 'generalized-method-of-moments' cannot be recorded as a synonym for generalized-moments (too many characters), but a moderator can easily discard the 'gmm' <-> 'generalized-moments' association that was suggested recently.
– chl
Oct 24 '13 at 17:54
• I've folded in the description of GMM that Dimitriy provided into generalized-moments tag, and wrote a strong language in gmm tag to discourage users from actually using it. Oct 25 '13 at 16:34
• Thanks, Stas! I think it should be clear now.
– chl
Oct 25 '13 at 17:08