Syntax for basic growth model with or... PreviousNext
Mplus Discussion > Growth Modeling of Longitudinal Data >
 Margot Jackson posted on Wednesday, February 13, 2008 - 11:57 am
Hi, I have data at 3 time points (0, 1 year later, and then 5 years later), and I'm trying to model change in an ordinal (three-category) outcome, and want to begin by just looking at the trend without any covariates. I'm using the following syntax (beginning from the "categorical" specification):

Categorical are y1 y2 y3 ;

Type = meanstructure;
Estimator= ml ;

level trend | y1@0 y2@1 y3@5 ;
[y1@1 y2 y3] ;
y1-y3 (1) ;
[level trend] ;

When I do this I get the following error: *** ERROR in Model command
The categorical variables in the growth model do not have the same number of categories. Use the CATEGORICAL option to allow the number of categories to differ for maximum likelihood estimation. Problem with: LEVEL TREND

I'm confused because each "bmicat" variable is coded identically, with three categories and no missings. Is there something obviously wrong here? I am brand new to MPlus and would appreciate any feedback!
 Linda K. Muthen posted on Wednesday, February 13, 2008 - 12:02 pm
It sounds like you are not reading your data correctly. You may have blanks in the data and are reading it with free format which is not allowed. Send your input, data, output, and license number to if you cannot figure it out.
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