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09-12-2014 02:56 PM

hello,

I have this warning. How can I resolve the problem?

WARNING: The covariance across equations (the S matrix) is singular. A generalized inverse was

computed by setting to zero the part of the S matrix for the following 9 equations

whose residuals are linearly dependent with residuals from earlier equations: aone atwo

athree afour afive asix anine aten power

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Posted in reply to sasphd

09-12-2014 03:17 PM

Not sure, what type of analysis is this, but most likely this is a problem of multicollinearity.

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Posted in reply to stat_sas

09-15-2014 08:22 AM

It is exact collinearity, in that one of the variables is a linear combination of some the others. That is why a generalized inverse is used. You have two choices--accept the GI approach (my preference) or reparameterize your model.

Steve Denham

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Posted in reply to SteveDenham

06-18-2017 07:02 AM

Hi Steve,

I also got a similar message as the other member (SASPHD) above.

Can you kindly provide a syntax on how to correct for singularity using the IV approach in a source-differentiated AIDS model?

Thanks.

Patrick