Date: Wed, 2 Mar 2011 15:09:08 -0500
Reply-To: Jonas Bilenas <jonas.bilenas@CHASE.COM>
Sender: "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From: Jonas Bilenas <jonas.bilenas@CHASE.COM>
Subject: Re: Survey logistic warnings
Have you run a collinearity diagnostic on your information matrix?
Preferably using PROC REG with the COLLIN option in the MODEL statement.
On Wed, 2 Mar 2011 14:22:52 -0500, Thevenet-Morrison, Kelly <Kelly_Thevenet-
>I am running a proc survey logistic on an NHANES sample. I run similar
models on the sample but I change the classification of my primary exposure
> I increased the max iteration from 25-50 and had the majority of the
models converge with no errors or warnings.
>However, a few of the models gave the following warnings:
>WARNING: Ridging has failed to improve the loglikelihood. You may want to
use a different ridging technique (RIDGING= option),
> or switch to using linesearch to reduce the step size
(RIDGING=NONE), or specify a new set of initial estimates
> (INEST= option).
>WARNING: The SURVEYLOGISTIC procedure continues in spite of the above
warning. Results shown are based on the last maximum
> likelihood iteration. Validity of the model fit is questionable.
>I changed the ridging to absolute in some of the models and that seemed to
take care of the error but not in all of them.
>I also get the warning
>WARNING: The information matrix is singular and thus the convergence is
>I change the convergence to the different options
>Four convergence criteria are allowed: ABSFCONV=, FCONV=, GCONV=, and
>But I continue to get the information matrix warning.
>I also checked the SAS-L archives but I only saw the option about changing
>Any help with these warnings would be greatly appreciated.
>Kelly Thevenet-Morrison MS
>Lead Programmer Analyst
>Department of Community and Preventive Medicine
>University of Rochester School of Medicine and Dentistry
>601 Elmwood Ave., box 644
>Rochester, NY 14642