Date:         Wed, 21 Sep 2005 16:27:57 -0400
Reply-To:     Peter Flom <flom@NDRI.ORG>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Peter Flom <flom@NDRI.ORG>
Subject:      Re: Proc Logistic,why are the main effects identical for 2
              populatio n subsets?
Comments: To: Todd.Case@FRX.COM
Content-Type: text/plain; charset=US-ASCII

Peter L. Flom, PhD
Assistant Director, Statistics and Data Analysis Core
Center for Drug Use and HIV Research
National Development and Research Institutes
71 W. 23rd St
http://cduhr.ndri.org
www.peterflom.com
New York, NY 10010
(212) 845-4485 (voice)
(917) 438-0894 (fax)


>>> Todd Case <Todd.Case@FRX.COM> 09/21/05 9:16 AM >>> wrote
<<<<
I am using 2 identical Proc Logistic statements (only difference is the
2 are subset using 2 different populations).  So the estimates of all
interaction terms which include the subset populations are different (as
expected) but the estimate for the main effect terms are identical (I
know this cant be the same because they are identcial to the 1/10000th
place)!
Any ideas?
>>>>

Coould you write back to SAS-L (not just to me) and provide the code?


Peter