Re: [R] ROC analysis

From: Eleni Christodoulou <elenichri_at_gmail.com>
Date: Wed, 19 Mar 2008 12:21:37 +0200

Richard, thanks, I think it will work. I will calculate the cutoff value and then, from the prediction object, find the fpr that is related to it and put it as argument to performance. I will keep you informed.

Eleni

On Wed, Mar 19, 2008 at 11:51 AM, Richard Pearson < richard.pearson_at_postgrad.manchester.ac.uk> wrote:

> Eleni
>
> Does the fpr.stop argument do what you want? This is described in
> ?performance under the details of the "auc" measure. Try, e.g.
>
> perform=performance(pred,measure="auc",fpr.stop=0.5)
>
>
> Richard.
>
>
> Eleni Christodoulou wrote:
> > Hello list,
> >
> > I am trying to perform ROC analysis and count the AUC in order to
> validate
> > my results. I use package ROCR. I would like to count the AUC not under
> the
> > cutoff found by "performance" but to use another cutoff that I
> calculate.
> > How could I change the following command in order to get what I want?
> > perform=performance(pred,measure="auc",x.measure="cutoff"), where pred
> is a
> > prediction object.
> >
> > Thank you very much,
> > Eleni
> >
> > [[alternative HTML version deleted]]
> >
> > ______________________________________________
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> >
> >
>
> ______________________________________________
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