[R] partial proportional odds model (PPO)

[Frank E Harrell Jr]

On 13 Dec 2003 10:11:19 +0100
Christoph Lehmann <christoph.lehmann at gmx.ch> wrote:

> Hi
> 
> Since the 'equal slope' assumption doesn't hold in my data I cannot use
> a proportional odds model ('Design' library, together with 'Hmisc'). I
> would like to try therefore a partial proportional odds model
> 
> Please, could anybody tell me, where to find the code and how to specify
> such a model
> 
> ..or any potential alternatives
> 
> many thanks for your kind help
> 
> christoph
> -- 
> Christoph Lehmann <christoph.lehmann at gmx.ch>

I do not know of an implementation of the partial PO model in S.  You can
easily fit continuation ratio ordinal response models in S using lrm and
glm, with easy-to-construct non-equal slope components, after suitable
expansion of the dataset (see Regression Modeling Strategies, Springer
2001 for a detailed case study using lrm, with code).

Frank Harrell

---
Frank E Harrell Jr   Professor and Chair           School of Medicine
                     Department of Biostatistics   Vanderbilt University