Date:         Wed, 11 Apr 2007 20:22:23 -0700
Reply-To:     David L Cassell <davidlcassell@MSN.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         David L Cassell <davidlcassell@MSN.COM>
Subject:      Re: Proc Glimmix without Random _residual_ VS Glimmix Macro
In-Reply-To:  <BAY139-F32F5170940E16FAAADF09FC15F0@phx.gbl>
Content-Type: text/plain; format=flowed

aneliecarsin@HOTMAIL.COM wrote:
>
>Dear SAS-lister,
>
>I would like to run a multi-level analysis on some data structured as
>follow: level 1=Patient, level 2=surgeon nested in hospital (level 3).  The
>outcome is potsop=0/1.
>I used the Macro %Glimmix before, and it works fine.
>Now, I wanted to use proc Glimmix (seems easier and give the Odds Ratio
>which save me time).
>Anyway, I translated the macro code to the procedure code as follow:
>
>%glimmix(   DATA = may06,
>     procopt =   method=reml covtest ,
>     stmts=%str(
>       class surgeon hospital hosp_ter;
>       id surgeon hospital ;
>       model postop=hosp_ter /  ddfm=kr ;
>       random int / subject=hospital ;
>       random int / subject=surgeon(hospital) ;
>     ),
>    error = binomial,
>    link = logit
>);
>run;
>
>proc glimmix DATA = may06;
>     class surgeon hospital hosp_ter;
>     id surgeon hospital ;
>     model postop=hosp_ter / ddfm=kr oddsratio link=logit dist=binomial ;
>     random int  / subject=hospital;
>     random int  / subject=surgeon(hospital) ;
>     nloptions tech=nrridg;
>     random _residual_;
>run;
>
>I just don't get why the RANDOM _residual_; is needed in the Proc Glimmix?
>Results are slighlty different when omitted and I wonder what results would
>be the correct ones? Any idea?
>
>Thanks for your help!
>
>Anne-Elie

Could you write back to SAS-L and explain how the data were collected?

This sounds like you have a multi-stage survey sample, in which case
you would be doing the wrong thing.  If this is a survey sample, and
if you do have the design information and the sampling weights, then
this could be a heck of a lot easier to analyze using PROC SURVEYLOGISTIC
instead.

HTH,
David
--
David L. Cassell
mathematical statistician
Design Pathways
3115 NW Norwood Pl.
Corvallis OR 97330

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