[R] Visualization of coefficients

[Achim Zeileis]

On Wed, 7 Jul 2010, Michael Friendly wrote:

> Tal Galili wrote:
>> Hello David,
>> Thanks to your posting I started looking at the function in the arm 
>> package.
>>  It appears this function is quite mature, and offers (for example) the
>> ability to easily overlap coefficients from several models.
>> 
>> I updated the post I published on the subject, so at the end of it I give 
>> an
>> example of comparing the coef of several models:
>> http://www.r-statistics.com/2010/07/visualization-of-regression-coefficients-in-r/
>> 
>> Thanks again for the pointer.
>> 
>> Best,
>> Tal
>
> Achim Zeileis wrote:
>> Re: more mature. arm's coefplot() is more flexible in certain respects, 
>> mine is more convenient in others. The overlay functionality is something 
>> arm's coefplot() is better in and it also as some further options (vertical 
>> vs. horizontal etc.). My coefplot() has the advantage that it does not need 
>> any modification as long as coef() and vcov() methods are available. 
>> Furthermore, "level" can specify the significance level (instead of always 
>> using one and two standard errors, respectively).
>> But it shouldn't be too hard to create a superset of all options.
>
>
> @Tal:
> For the example using library(arm) and the Mroz data, you posted the wrong 
> image.  And loose the intercept in the example.
>
> @Achim:
> It would be worthwhile combining the generality of your version with the
> overlay capability of the arm version, which is extremely useful for model 
> comparison.

Yes, that's what Thomas Lumley already suggested as well.

> However, the arm version uses S4 methods.

Yes. If I do get round to fully implement this, I would take the same 
approach as with the coeftest() function. That is: Having a default method 
that typically works out of the box, and a thin layer of S3 methods, in 
case it needs adaption. The latter is necessary for example for "multinom" 
objects where the coef() method returns a matrix whose elements need to be 
matched to the elements of the matrix returned by vcov().

Best,
Z

> -Michael
>
>
> -- 
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