GMM for skewed positive dependent var... PreviousNext
Mplus Discussion > Growth Modeling of Longitudinal Data >
 SF Wang posted on Friday, August 08, 2014 - 1:20 pm
Dear professors,

when we do GMM for positive extremely-skewed dependent variables, should we do transformation so that the dependent variable is roughly normally distributed?

The variable we'd like to model varies from 0 to 18, but most scored from 0-2.

 Bengt O. Muthen posted on Friday, August 08, 2014 - 4:15 pm
I am not fond of making variable transformations, but instead prefer to make the model accommodate the variables they way they are.

You should investigate why/how the DVs are so skewed. Do they have floor or ceiling effects in which case 2-part GMM might be more suitable? Or, are they skewed without floor/ceiling effects in which case the new option Distribution = skewt can be used.
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