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Mplus Discussion > Growth Modeling of Longitudinal Data >
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 Sarah Racz posted on Tuesday, February 05, 2013 - 12:54 pm
Dear Drs. Muthen,
I am conducting an observed (continuous covariate; e.g., SES) by latent variable (intercept and slope) interaction in a latent growth curve model using the XWITH command. When running the analyses I get the following warning:

"WARNING: THE MODEL ESTIMATION HAS REACHED A SADDLE POINT OR A POINT WHERE THE OBSERVED AND THE EXPECTED INFORMATION MATRICES DO NOT MATCH. AN ADJUSTMENT TO THE ESTIMATION OF THE INFORMATION MATRIX HAS BEEN MADE. THE CONDITION NUMBER IS -0.419D-02. THE PROBLEM MAY ALSO BE RESOLVED BY DECREASING THE VALUE OF THE MCONVERGENCE OR LOGCRITERION OPTIONS OR BY CHANGING THE STARTING VALUES OR BY USING THE MLF ESTIMATOR."

I have decreased the mconvergence and logcriterion options and increased the starting values, which did not resolve the warning. I also have weights in my data, which means I cannot use the MLF estimator (however, the warning does go away if I remove the weights and use the MLF estimator). Even with this saddle point warning, I receive output which is interpretable and includes standard errors (although not standardized results). Does this mean I can ignore the error? Or do I need to try something else?

Thank you so much for your assistance!
-Sarah Racz
 Bengt O. Muthen posted on Tuesday, February 05, 2013 - 1:48 pm
You can ignore the message.
 Sarah Racz posted on Tuesday, February 05, 2013 - 2:19 pm
Great - thank you Bengt for the quick reply!
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