[R] Step wise regression

[(Ted Harding)]

On 03-May-05 Frank E Harrell Jr wrote:
> walmir-rodrigues wrote:
>> Dear Fellows,
>> 
>> How can I do to proced a step wise regression in R, if it´s possible ?
>> 
>> Thanks,
>> 
>> Walmir 
> 
> Here is an easy approach that will yield results only slightly less 
> valid than one actually using the response variable:
> 
> x <- data.frame(x1,x2,x3,x4,..., other potential predictors)
> x[,sample(ncol(x))]
> 
>:-)   -Frank

Frank, you are a sneaky subversive! But you have given me a
technical clue for a project long near to my heart (with
Andy's important "random parsimony" refinement).

This is to implement software-driven Clinical Trials articles,
for submission to standard peer-reviewed journals.

The underlying engine would be the dada-engine. For samples
of what this can generate, visit

  http://www.elsewhere.org/cgi-bin/postmodern

repeatedly (or click on the "To generate another essay, follow
this link" link you will find just below the article generated;
repeat ad libitum).

Also at the foot of the page, you will find links to explanations
of how it works. See also

  http://dev.null.org/dadaengine/

The basis is that articles of certain kinds have a predictable
structure, and utilise terminology, phrases, sentence-structures
and substantive elements drawn from typical usage, and are such
that the real thing is indistiguishable from the results of sampling
these elements at random, under the control of a rulebased recursive
transition network automaton.

Tailor-made for Clinical Trials, methinks. (Mind you, someone
once did a lot of work setting up the rulebase for the PostModern
Lit Crit genre which is what you get in the above samples).

Best wishes,
Ted.