Date: Fri, 4 Jul 2008 10:29:24 +0530
ReplyTo: Praveen <ipkrishna@GMAIL.COM>
Sender: "SAS(r) Discussion" <SASL@LISTSERV.UGA.EDU>
From: Praveen <ipkrishna@GMAIL.COM>
Subject: Combining categories and estimating Odds Ratio
ContentType: text/plain; charset=ISO88591
Hi Listers,
I am faced with problem where I have the customer survey responses. I am
trying to build up an ordinal logistic regression with the 11point ordered
categories in response variable. Upto this point it works out fine. Now I
want to compare few clubbed categories, i.e.,
New Category "A" = 1,2,3,4,5 combined from original 11point responses
New Category "B"=6,7,8,9 combined from original 11point responses
New Category "C"=10,11 combined from original 11point responses
I did it using running three different logistic regression comparing (A,B),
(B,C) & (A,C) and got the estimates of odds ratio for each combination which
was making a lot of sense to me.
But other guys in my group said clubbing the categories is not a good idea
as it results in loss of information, I completely agree with them. But the
problem is with the technique. None of us know how to get to different
estimates of odds ratios for different combinations mentioned above. I know
we can compute individual probabilities on each observations using ordinal
logistic regression, but I am interested in odds ratio which are
different/relevant for clubbed categories.
It would really help me if someone can guide me through getting my 'desired'
result by using OLR on 11point dependent variable.

Regards,
Praveen Krishna

All measurements are subject to variation.
