R help - Feb 2008 - how to create ROC curve for 2 dimensional classifiers

Hi,

I understand for 1 d classifiers, you can use ROCR package.

Is there a package you can plot ROC curve for 2d classifiers?  One of
my colleagues asked me about this.  I have been quite puzzled,
conceptually, how you can do the ROC curve for 2d classifiers.  Can
someone share his/her knowledge or experience?

Thanks in advance.

-- 
Waverley @ Palo Alto

I'm not aware of any packages for doing such plots. Conceptually, 
presumably a ROC curve for a 2d classifier would be a 3d chart, with 
x-axis being FPR for 1st classifier, z-axis being FPR for 2nd classifier 
and y-axis being TPR. You would get a "ROC surface" rather than a ROC 
curve. Does that make sense?

Regards

Richard.


Waverley wrote:
> Hi,
>
> I understand for 1 d classifiers, you can use ROCR package.
>
> Is there a package you can plot ROC curve for 2d classifiers?  One of
> my colleagues asked me about this.  I have been quite puzzled,
> conceptually, how you can do the ROC curve for 2d classifiers.  Can
> someone share his/her knowledge or experience?
>
> Thanks in advance.
>
>

The are some papers on the topic (google for "roc surfaces"), but no R
packages for multi-class ROC analysis.
I personally have some doubts about the practical value of these
approaches in the case of more than two classes, but others may
disagree.

Kind regards,
  Tobias


On Thu, Feb 21, 2008 at 8:26 PM, Waverley <waverley.paloalto at gmail.com>
wrote:
> Hi,
>
>  I understand for 1 d classifiers, you can use ROCR package.
>
>  Is there a package you can plot ROC curve for 2d classifiers?  One of
>  my colleagues asked me about this.  I have been quite puzzled,
>  conceptually, how you can do the ROC curve for 2d classifiers.  Can
>  someone share his/her knowledge or experience?
>
>  Thanks in advance.
>
>  --
>  Waverley @ Palo Alto
>
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