LISTSERV at the University of Georgia
Menubar Imagemap
Home Browse Manage Request Manuals Register
Previous messageNext messagePrevious in topicNext in topicPrevious by same authorNext by same authorPrevious page (September 2000, week 2)Back to main SAS-L pageJoin or leave SAS-L (or change settings)ReplyPost a new messageSearchProportional fontNon-proportional font
Date:         Fri, 8 Sep 2000 17:34:29 -0700
Reply-To:     Cassell.David@EPAMAIL.EPA.GOV
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         "David L. Cassell" <Cassell.David@EPAMAIL.EPA.GOV>
Subject:      Re: Poisson Vs Negative Binomial Regressions
Comments: To:
Content-type: text/plain; charset=us-ascii

Ogbonnaya John Nwoha wrote: > How can I determine the better of a poisson regression result and a > negative binomial regression result. Attached are the outputs of an > actual regression. Which one is better?

I would hesitate to judge "better" based on mere statistical performance, particularly when your test statistics indicate that neither fit is really a lot better than the other. [I did have real trouble reading your attachments so I could have overlooked something - in future please do not use MIME in a mailing list which is gateway'd to a Usenet newsgroup!]

You'll be better off attacking this problem from a different direction. Or two. Here are two to start with. First, how do the residual plots look? Is one clearly a better fit than the other? Is one clearly meeting the underlying assumptions of the modeling process better than the other? And second [this is where I would actually start if I were consulting on this], what are the underlying features of your process? How do you expect the process to work, and hence which of the two models is a more rational model from the *scientific* perspective?

"Don't let statistics drive your science; let the science drive your statistics."

David -- David Cassell, OAO Corp. Senior computing specialist mathematical statistician

Back to: Top of message | Previous page | Main SAS-L page