Date:         Fri, 19 Sep 2008 01:39:43 -0400
Reply-To:     Wensui Liu <liuwensui@GMAIL.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Wensui Liu <liuwensui@GMAIL.COM>
Subject:      Re: Logistic, Genmod, and Repeated Measures
Comments: To: stringplayer_2@yahoo.com
In-Reply-To:  <771246.21385.qm@web32205.mail.mud.yahoo.com>
Content-Type: text/plain; charset=ISO-8859-1

well, dale, are you suggesting a repeated measure has to be a mixed model
with random effect?

On Fri, Sep 19, 2008 at 1:08 AM, Dale McLerran <stringplayer_2@yahoo.com>wrote:

> Well, subject looks like a random effect.  Whether to use GLIMMIX
> or GENMOD (or NLMIXED!) has more to do with whether a marginal
> interpretation is desired or whether a conditional interpretation
> is desired.  That is, do we want to make statements about average
> effects in a population or about effects that might be observed
> for an individual in some population.
>
> If you want a population average interpretation, then you want
> to use GENMOD.  If you want a subject-specific interpretation,
> then you want to fit a random effects model.
>
> Dale
>
> ---------------------------------------
> Dale McLerran
> Fred Hutchinson Cancer Research Center
> mailto: dmclerra@NO_SPAMfhcrc.org
> Ph:  (206) 667-2926
> Fax: (206) 667-5977
> ---------------------------------------
>
>
> --- On Thu, 9/18/08, Wensui Liu <liuwensui@GMAIL.COM> wrote:
>
> > From: Wensui Liu <liuwensui@GMAIL.COM>
> > Subject: Re: Logistic, Genmod, and Repeated Measures
> > To: SAS-L@LISTSERV.UGA.EDU
> > Date: Thursday, September 18, 2008, 8:25 PM
> > peter,
> >
> > i have to disagree with you and see no point to use
> > glimmix. where is the
> > random effectin bruce's model?
> >
> > On Thu, Sep 18, 2008 at 1:28 PM, Peter Flom <
> > peterflomconsulting@mindspring.com> wrote:
> >
> > > "Bruce A." <coreklenelim@YAHOO.COM>
> > wrote
> > > >
> > > >I'm trying to analyze a dataset with repeated
> > observations on the same
> > > >subject with a dependent variable which is
> > dichotomous.  So I used PROC
> > > >GENMOD with the repeated statement.  However, when
> > I compare that to the
> > > >output when I use PROC LOGISTIC (which ignores
> > dependency) I get the same
> > > >estimates, the same confidence intervals of those
> > estimates, and therefore
> > > >I get the same p-hat values.
> > > >
> > > >Shouldn't I get different answers?  Am I using
> > PROC GENMOD wrong?  Am I
> > > >going crazy?
> > > >
> > > >These are the two codes I used:
> > > >
> > >
> > > Not sure about your genmod code, but I think you
> > should be using PROC
> > > GLIMMIX
> > >
> > > Peter
> > >
> > > Peter L. Flom, PhD
> > > Statistical Consultant
> > > www DOT peterflom DOT com
> > >
> >
> >
> >
> > --
> > ===============================
> > WenSui Liu
> > Acquisition Risk, Chase
> > Email : wensui.x.liu@chase.com
> > Blog : statcompute.spaces.live.com
> > ===============================
>



--
===============================
WenSui Liu
Acquisition Risk, Chase
Email : wensui.x.liu@chase.com
Blog   : statcompute.spaces.live.com
===============================