Date:         Thu, 5 Feb 2009 07:39:23 -0800
Reply-To:     Zai Saki <zaisaki@GMAIL.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Zai Saki <zaisaki@GMAIL.COM>
Organization: http://groups.google.com
Subject:      Re: Adjacent Category Models
Comments: To: sas-l@uga.edu
Content-Type: text/plain; charset=ISO-8859-1

Thanks!
Zai


On Feb 5, 3:10 am, John Hendrickx <John2.Hendri...@gmail.com> wrote:
> Hello Zai,
>
> One way of doing this is as a "multinomial conditional logit" (MCL)
> model. The idea is to use program for a conditional logit model to
> estimate an multinomial logit model. This will produce the same
> results but allows you to impose constraint on the parametrization of
> the dependent variable.
>
> More information is available athttp://home.wanadoo.nl/john.hendrickx/statres/mcl/
> The LR.SAS program athttp://home.wanadoo.nl/john.hendrickx/statres/mcl/sas/
> shows how to estimate a multinomial logistic model using PROC PHREG.
> For a dependent variable with 3 categories, you'd have to make the
> following modification:
>
> array y{3};
> do i=1 to 3;
>     if newy <= i then y[i]=1-i/3;
>     else y[i]=-i/3;
> end;
>
> (And create interactions of y: with your independent variables).
>
> Good luck,
>
> John Hendrickx
>
> Statistician
> Clinquest Europe BV, Oss - The Netherlandswww.clinquest.com
>
> On 3 feb, 17:50, Zai Saki <zais...@gmail.com> wrote:
>
>
>
> > Hi All,
> > I am trying to build a model with an ordinal dv (scale 1 to 4). We are
> > looking for something like theadjacentcategorymodel that is
> > available in proc catmod. However our independent variables are
> > ratings on a scale of 1 to 10 and we have upto 25 of these. So proc
> > catmod is ruled out.
>
> > One key goal is to have unique parameter estimates for each transition
> > unlike a proportional odds model.
>
> > I believe we can do it in proc genmod by specifying a customized link
> > using "fwdlink", "invlink", "deviance", and "variance" statements as
> > such a link is not available inherently in proc genmod.
>
> > Any suggestions on how to fit such a model using proc genmod or any
> > other sas procedure would be greatly appreciated.
>
> > Thanks,
> > Zai- Hide quoted text -
>
> - Show quoted text -