[R] working with ordinal predictor variables?

Bert Gunter bgunter.4567 at gmail.com
Thu Oct 5 21:35:15 CEST 2017

I would consider this is a question for a statistics forum such as
stats.stackexchange.com, not R-help, which is about R programming. They do
sometimes intersect, as here, but I think you need to *understand what
you're doing* before you write the R code to do it.

Obviously, IMO.


Bert Gunter

"The trouble with having an open mind is that people keep coming along and
sticking things into it."
-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )

On Thu, Oct 5, 2017 at 10:54 AM, Alexandra Thorn <alexandra.thorn at gmail.com>

> I'm trying to develop a linear model for crop productivity based on
> variables published as part of the SSURGO database released by the
> USDA.  My default is to just run lm() with continuous predictor
> variables as numeric, and discrete predictor variables as factors, but
> some of the discrete variables are ordinal (e.g. drainage class, which
> ranges from excessively drained to excessively poorly drained), but
> this doesn't make use of the fact that the predictor variables have a
> known order.
> How do I correctly set up a regression model (with lm or similar) to
> detect the influence of ordinal variables?
> How will the output differ compared to the dummy variable outputs for
> unordered categorical variables.
> Thanks,
> Alex
> ______________________________________________
> 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.

	[[alternative HTML version deleted]]

More information about the R-help mailing list