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05-14-2017 06:27 AM - edited 05-14-2017 06:29 AM

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,

--------------------------------------------------------------------------------

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;

---------------------------------------------------------------------------------

Accepted Solutions

Solution

05-20-2017
07:05 AM

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Posted in reply to Tissue5454

05-15-2017 09:06 AM

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Posted in reply to Tissue5454

05-14-2017 07:13 AM

Why you include subject term in the independent variables ?

Try option type=chol.

random intercept/ subject=fid type=chol ;

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Posted in reply to Ksharp

05-14-2017 07:50 AM

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

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Posted in reply to Tissue5454

05-15-2017 09:06 AM

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Posted in reply to Ksharp

05-16-2017 08:37 PM

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

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Posted in reply to Tissue5454

05-17-2017 08:12 AM

I am glad that worked and pround of your effort .

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Posted in reply to Tissue5454

05-10-2018 01:42 PM

Hey there, tissue5454 -

Do you mind sharing the syntax of your PARAM fix. I am having a similar code and error log, and would like to know how/where the PARAM fix was inserted.

Many thanks, in advance.

-R

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Posted in reply to rplum64

05-10-2018 08:14 PM

Sorry... I could not find the above file.

tissue5454

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Posted in reply to rplum64

05-16-2018 05:00 PM

Lots of good information in this recent SGF paper by Kathleen Kiernan (2018) of SAS, including possible solutions to the warning message that you are getting

Insights into Using the GLIMMIX Procedure to Model Categorical Outcomes with Random Effects

This older paper by Kiernan, Tao, and Gibbs (2012) is good, too

Tips and Strategies for Mixed Modeling with SAS/STAT® Procedures

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05-16-2018 08:24 PM

Thank you sld !

Your information is valuable for me and rplum64.

These papers containe some examples which use "PARMS" statement.

Thank you again for your help.