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Re: st: Help please re Ocratio


From   "Anders Alexandersson" <andersalex@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Help please re Ocratio
Date   Tue, 30 Oct 2007 08:50:40 -0400

Please provide complete references. Rory Wolfe's command -ocratio-
uses a "forward stopping" continuation ratio model, P[Y=j|Y>=j] (i.e.,
like "Armstrong and Sloan" below), but with reverse sign of the slope
compared with logistic regression on expanded data so that the sign of
the slope is the same as in the usual proportional odds model.

Anders Alexandersson
andersalex@gmail.com

Jon Heron (ALSPAC) <Jon.Heron@bristol.ac.uk> wrote:
>
>  I would like to fit a continuation ratio model to a 6-level outcome
>  using ocratio. I would then like to assess the constancy of model
>  parameters by fitting a series of logistic models
>
>  A quick lit search is showing variability in which comparisons are being
>  made with a CR model.
>
>   e.g. for 3-level outcome - 1/2/3
>
>   Armstrong and Sloan (1989)
>     1 versus 2 & 3
>     2 versus 3
>
>   Manor, Matthews and Power (2000)
>     1 versus 2
>     1 & 2 versus 3
>
>   Greenland (1994)
>     2 & 3 versus 1,2 & 3
>     3 versus 2 & 3
>
>  I imagine these are all permitted alternatives, but i would like to know
>  which particular comparisons are made using ocratio so I can fit the
>  appropriate logistic models.
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