Date:         Fri, 5 Sep 2008 15:00:51 -0700
Reply-To:     SR Millis <srmillis@yahoo.com>
Sender:       "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From:         SR Millis <srmillis@yahoo.com>
Subject:      Re: Logistic Regression - Threshold effect sizes?
Comments: To: Jon Bernard <jon563@gmail.com>
In-Reply-To:  <cd3517fa0809051442y3fbf7dfasccc44c3778ab4bc7@mail.gmail.com>
Content-Type: text/plain; charset=us-ascii

Jon,

What is puzzling in the results?

Have you examined the degree of collinearity among the predictors/covariates?



Scott R Millis, PhD, MEd, ABPP (CN,CL,RP), CStat
Professor & Director of Research
Dept of Physical Medicine & Rehabilitation
Wayne State University School of Medicine
261 Mack Blvd
Detroit, MI 48201
Email:  smillis@med.wayne.edu
Tel: 313-993-8085
Fax: 313-966-7682


--- On Fri, 9/5/08, Jon Bernard <jon563@gmail.com> wrote:

> From: Jon Bernard <jon563@gmail.com>
> Subject: Logistic Regression - Threshold effect sizes?
> To: SPSSX-L@LISTSERV.UGA.EDU
> Date: Friday, September 5, 2008, 5:42 PM
> Fellow SPSSers,
>
> I am struggling with a logistic regression issue and
> thought I'd put it out
> to the list for some clarity.
>
> The dependent variable of interest is a binary event (0 =
> Did not happen, 1
> = Did happen).  The independent variables of interest are
> ordinal
> attitudinal survey items, with responses on a 5-point scale
> (1 = Strongly
> Disagree, 5 = Strongly Agree).  I have been using logistic
> regression for
> the analysis, but either I'm missing something in the
> results output or I'm
> using the wrong statistical technique.  I have an inkling
> that the intervals
> between categories of the independent variables are not all
> equal.  In other
> words, I think that the impact on the dependent variable of
> an independent
> variable score of 3 vs. one of 2 is greater than that of a
> score of 5 vs.
> one of 4.  Is that clear?  If so, what would you recommend
> in order to test
> that hypothesis?  Is there a class of techniques designed
> particularly for
> this kind of test?
>
> Very many thanks in advance for your assistance with this
> matter.
>
> Kind regards,
>
> Jon
>
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