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Nick Mumford posted on Wednesday, September 05, 2012 - 5:49 pm
Thanks for that info Linda. I'm currently working my way through the lecture videos you've posted on the Mplus site, which have been very helpful in getting started.
That said, as a psychologist (rather than a statistician), I will likely have further questions as things progress, so it's good to have some options to follow up when the time comes.
Nick Mumford posted on Tuesday, September 11, 2012 - 8:38 pm
Hi Linda and Bengt,
Just wanted to follow up with a question regarding the model we've discussed above.
On running the model I've received an error message mixed in with the results as follows:
WARNING: THE LATENT VARIABLE COVARIANCE MATRIX (PSI) IN GROUP C12 IS NOT POSITIVE DEFINITE. THIS COULD INDICATE A NEGATIVE VARIANCE/ RESIDUAL VARIANCE FOR A LATENT VARIABLE, A CORRELATION GREATER OR EQUAL TO ONE BETWEEN TWO LATENT VARIABLES, OR A LINEAR DEPENDENCY AMONG MORE THAN TWO LATENT VARIABLES. CHECK THE TECH4 OUTPUT FOR MORE INFORMATION. PROBLEM INVOLVING VARIABLE S.
This error is repeated 12 times in the output, once for each of our 12 groups.
I'm struggling to know what the next step to take here is, and whether this means that the model results we've gotten should be discarded.