Programming the statistical procedures from SAS

WARNING: Obtaining minimum variance quadratic unbiased estimates as starting values for the covarian

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WARNING: Obtaining minimum variance quadratic unbiased estimates as starting values for the covarian

[ Edited ]

Hi all, 

I am trying to do logistic regression with random effiect for binary data by GLIMMIX.

However, I get warinig message as follows;

 

WARNING: Obtaining minimum variance quadratic unbiased estimates as starting values for the covariance parameters failed

 

Anyone know how I can overcome this problem?

Thanks,

 

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proc glimmix data=logitbank method=quad;
class fid;
model ydat2(event='1') = D1013 fid*D1013
/dist = binary link=logit ddfm=none solution;
random intercept/ subject=fid;
output out =glmout pred =xbeta pred(ilink) =predprob;
covtest;
run;

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‎05-20-2017 07:05 AM
Grand Advisor
Posts: 9,458

Re: WARNING: Obtaining minimum variance quadratic unbiased estimates as starting values for the cova

Or try PARAM statement . and I quoted here.
"The PARMS statement specifies initial values for the covariance or scale parameters, or it requests a grid search over several values of these parameters in generalized linear mixed models."

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Grand Advisor
Posts: 9,458

Re: WARNING: Obtaining minimum variance quadratic unbiased estimates as starting values for the cova

Why you include subject term in the independent variables ?

Try option type=chol.

 

random intercept/ subject=fid type=chol ;

Occasional Contributor
Posts: 10

Re: WARNING: Obtaining minimum variance quadratic unbiased estimates as starting values for the cova

Hi Ksharp!

 

Thank you for reply!

 

>Why you include subject term in the independent variables ?

 

Because I want to include not only random intercept but also random slope.

 

>Try option type=chol.

 

I received same warning message: WARNING: Obtaining minimum variance quadratic unbiased estimates as starting values for the covariance parameters failed...

Tissue5454

 

 

Solution
‎05-20-2017 07:05 AM
Grand Advisor
Posts: 9,458

Re: WARNING: Obtaining minimum variance quadratic unbiased estimates as starting values for the cova

Or try PARAM statement . and I quoted here.
"The PARMS statement specifies initial values for the covariance or scale parameters, or it requests a grid search over several values of these parameters in generalized linear mixed models."

Occasional Contributor
Posts: 10

Re: WARNING: Obtaining minimum variance quadratic unbiased estimates as starting values for the cova

Hi Ksharp!

 

Thank you for reply!

 

I tried PARAM statement and succeed in getting result!

I think the warning message;

"WARNING: Obtaining minimum variance quadratic unbiased estimates as starting values for the covariance parameters failed" tend to come up when the model is too complicated.

In my case, independent variable "D1013" is nonsignificant .

 

Thank you again,

 

tissue5454

 

Grand Advisor
Posts: 9,458

Re: WARNING: Obtaining minimum variance quadratic unbiased estimates as starting values for the cova

I am glad that worked and pround of your effort .

☑ This topic is SOLVED.

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