Date: Wed, 18 Jun 2003 14:21:49 0800
ReplyTo: Dan Jeffers <ojodelmar@HOTMAIL.COM>
Sender: "SAS(r) Discussion" <SASL@LISTSERV.UGA.EDU>
From: Dan Jeffers <ojodelmar@HOTMAIL.COM>
Subject: binary outcomes and repeated observations
ContentType: text/plain; format=flowed
Dear SASL readers,
I am working with a dataset composed of a series of explanatory variables
and a binary response. My approach to analysis had been using PROC GENMOD
to model the probability of the occurrence of the response in relation to
the explanatory variables. However, the data are from repeated observations
taken from the same set of subjects over time.
Is there a maximum likelihood based approach to analyzing this type of data?
I have read of populationaverage logistic regression models to deal with
correlation within subects, is this type of analysis available in SAS?
ALso, is there a way to look at the correlation within observations taken on
the same subjects to see if the correlation is significant to potentially
justify taking a standard logistic regression approach as if all
observations were independent? And finally, is the problem of correlation
among outcomes measured from the same subject related to the problem over
overdispersion, i.e. will acounting for overdispersion using a variance
inflation factor deal with correlation among repeated observations?
Thanks for your help.
Dan Jeffers
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