Date:         Thu, 29 Sep 2005 14:14:07 -0500
Reply-To:     "Nick ." <ni14@MAIL.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         "Nick ." <ni14@MAIL.COM>
Content-Type: text/plain; charset="iso-8859-1"

Thanks David. So, we do bootsrapping to know, say, at the 95% level that the C-statistic is between, say, 0.65 and 0.71 as an example. How does that help me any? I built a logistic model, I am happy with the results, I get a c-statistic of 0.65, why do I now need to do more work to get a CI on this? And why not do all the others to? I think proc logistic gives us 3 or 4 such numbers not just c. Aside from some pesky boss, is there a reason for doing this, is what the crux of my question is.
NICK

----- Original Message -----
From: "David Neal"
To: "'Nick .'" , SAS-L@LISTSERV.UGA.EDU
Subject: RE: Bootstrapping a C statistic
Date: Thu, 29 Sep 2005 10:59:49 -0800

Nick,
In logistic regression, SAS only provides a single C statistic. If you want
a confidence interval, you will need to do something like bootstrapping.
David Neal
-----Original Message-----
From: SAS(r) Discussion [mailto:SAS-L@LISTSERV.UGA.EDU] On Behalf Of Nick .
Sent: Thursday, September 29, 2005 10:48 AM
To: SAS-L@LISTSERV.UGA.EDU
Subject: Bootstrapping a C statistic
Hello all,
I was reading this topic about Bootstrapping a C statistic from proc
logistic modeling. My question is, why does one wish to do bootstraping on
this? I don't see the meaning of this post because I don't know what it is
we are trying to see here.
NICK
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