Date:         Thu, 31 Oct 2002 08:31:22 -0800
Reply-To:     "Parise, Carol A." <PariseC@sutterhealth.org>
Sender:       "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From:         "Parise, Carol A." <PariseC@sutterhealth.org>
Subject:      logit linearity in ordinal logistic
Comments: To: Marcos Sanches <marcos_sanches@gallup.com>
Content-Type: text/plain; charset=us-ascii

Hi all,

One of the assumptions of logistic regression when using a continuous
predictor is that the variable is liner in the log odd of the DV. The way I
have been doing this in SPSS for 2-category logistic regression is by taking
the contiunous variable and making quartiles or quintiles out of it and then
sticking it a logistic model with the DV. if the ORs increase or decrease
linearly for each category of the DV then I say this is linear in the log
odds and the assumption is met. Is this the same approach that needs to be
taken for ordinal logistic regression or is there a more streamlined method
of testing this assumption that i'm missing?

Thanks for any ideas.

Carol
Sacramento CA