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 Alcohol Study posted on Monday, April 25, 2011 - 6:28 pm
Hello Drs. Muthen,

I am running a path model with a categorical predictor. Specifically, I have fne (social anxiety scores), a mood variable (condition) and the interaction term (fnexcond) as predicting two mediators (tension reduction and enhancement cognitions) and two measures of alcohol urges (pos or neg reinf. urges).

I run the model with the following code:

IAT_TR IAT_EN ON cfne_m ccond fnexcond;
NEGreinf POSreinf ON cfne_m ccond fnexcond;
NEGreinf ON IAT_TR IAT_EN;
POSreinf ON IAT_EN;

Cfne_m WITH ccond fnexcond;
Ccond WITH fnexcond;
IAT_TR WITH IAT_EN;
POSreinf WITH negreinf;

And get this error:

THE MODEL ESTIMATION TERMINATED NORMALLY

THE STANDARD ERRORS OF THE MODEL PARAMETER ESTIMATES MAY NOT BE
TRUSTWORTHY FOR SOME PARAMETERS DUE TO A NON-POSITIVE DEFINITE
FIRST-ORDER DERIVATIVE PRODUCT MATRIX. THIS MAY BE DUE TO THE STARTING
VALUES BUT MAY ALSO BE AN INDICATION OF MODEL NONIDENTIFICATION. THE
CONDITION NUMBER IS 0.167D-15. PROBLEM INVOLVING PARAMETER 31.

According to TECH1, parameter 31 is the condition variable. Initially it was coded using -.5 and .5, so I tried it with a 0 and 1 coding as well and received the same error. I know the variables are not skewed or kurtotic.

Any idea why this might be happening?

Thanks
 Linda K. Muthen posted on Monday, April 25, 2011 - 8:14 pm
Please send your full output and license number to support@statmodel.com.
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