R help - Oct 2015 - additive proportional odds model in R

Hi all!
I'm looking for a way to fit an additive proportional odds model in R since
I need to analyse ordinal data. 
The polr() function of the MASS package of R allows only to fit a linear
proportional odds model so I can't use it. 
The gam() function of the gam package of R allows to fit additive models and
generalized additive models. This package uses smoothing splines and loess
as smoothers. I've read the documentation and it doesn't seem to be
possible
to fit an additive proportional odds model in R.      
Do you know which function should I use?
Thank you in advance.



--
View this message in context:
http://r.789695.n4.nabble.com/additive-proportional-odds-model-in-R-tp4713259.html
Sent from the R help mailing list archive at Nabble.com.

On Oct 7, 2015, at 3:33 AM, Neverstop wrote:
> Hi all!
> I'm looking for a way to fit an additive proportional odds model in R
since
> I need to analyse ordinal data. 
> The polr() function of the MASS package of R allows only to fit a linear
> proportional odds model so I can't use it. 
Can you explain the additional requirements you understand for your request. The
polr function is additive on the log-odds scale.
> The gam() function of the gam package of R allows to fit additive models
and
> generalized additive models. This package uses smoothing splines and loess
> as smoothers. I've read the documentation and it doesn't seem to be
possible
> to fit an additive proportional odds model in R.      
Are you looking for an identity link with binomial errors? 
> Do you know which function should I use?
I doubt that it would allow a identity link, but the `lrm` function in `pkg:rms`
is also used for ordinal proportional odds models. It supports several spline
representations of functional form.

> Thank you in advance.
> --
> View this message in context:
http://r.789695.n4.nabble.com/additive-proportional-odds-model-in-R-tp4713259.html
> Sent from the R help mailing list archive at Nabble.com.
I think you should understand that Nabble postings to R-help will soon not be
allowed.
> ______   So you _should_ read    ________________________________
R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

-- 

David Winsemius
Alameda, CA, USA

Thank you David Winsemius for the answer.

With the ambiguous term "additive proportional odds model", I meant
the
nonparametrical generalization of the parametrical proportional odds model.
In other words, I meant to fit a generalized additive model (GAM) with a
cumulative logit as link function.
>I think you should understand that Nabble postings to R-help will soon not
be allowed. 
I didn't know that. Why? Should I post this topic somewhere else?



--
View this message in context:
http://r.789695.n4.nabble.com/additive-proportional-odds-model-in-R-tp4713259p4713317.html
Sent from the R help mailing list archive at Nabble.com.