THE MODEL MAY NOT BE IDENTIFIED PreviousNext
Mplus Discussion > Growth Modeling of Longitudinal Data >
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 Nathan Smith posted on Thursday, September 15, 2016 - 2:25 pm
Hello, I am estimating a growth curve model and trying to find the proper parametric curve that most appropriately fits the data. So, model 1 was an estimate of the intercept and slope only - bad model fit. Model 2 adds a quadratic - model fit improves significantly, but still bad. I try a model with a cubic - error message.

"THE STANDARD ERRORS OF THE MODEL PARAMETER ESTIMATES COULD NOT BE COMPUTED. THE MODEL MAY NOT BE IDENTIFIED. CHECK YOUR MODEL."

I check the problem parameter, its the variance of the intercept (wasn't a problem in the previous models). I would appreciate some help in understanding how to deal with this. My belief is that the cubic model will be better than the quadratic.
 Linda K. Muthen posted on Thursday, September 15, 2016 - 3:13 pm
Please send the output and your license number to support@statmodel.com.
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