Date: Sun, 17 Jan 2010 18:11:06 -0800
Reply-To: haiyan chen <haiyan_c@YAHOO.COM>
Sender: "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From: haiyan chen <haiyan_c@YAHOO.COM>
Subject: Question regarding PROC SURVEYLOGISTIC
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I am running logistic regression to the complex survey data using PROC SURVEYLOGISTIC and got some strange outputs:
My program was as follows:
Proc surveylogistic data=one;
model response (event='1') = predictor;
The predictor has 5 levels (originally were represented by 5 binary variables: level1, level2, level3, level4, and levelm). Before running the model, I've made the desired reference group, level4, as the highest level of predictor by setting predictor=1*level1+2*level2+3*level3+4*levelm+5*level4;
Some strange outputs I got showed that, for example, the odds ratio (95%CI) for level2 was estimated 1.50(1.20, 1.99) with a p-value =0.87!
I can't come out with a reasonable explanation of this output. I was wondering if Anybody on this list has ever encountered the situation or know why so?
Many thanks in advance!