On 1/24/07, Frank E Harrell Jr <f.harrell@vanderbilt.edu> wrote:
>
> nitin jindal wrote:
>
> Using a cutoff is not a good idea unless the utility (loss) function is
> discontinuous and is the same for every subject (in the medical field
> utilities are almost never constant).  And if you are using the data to
> find the cutoff, this will require bootstrapping to penalize for the
> cutoff not being pre-specified.


Thnx for this info. If I still have to use cutoff, I will do bootstrapping.
I dont know any alternative to this to compute precision/recall for logistic
regression model.

No, that is not clear.  The overall classification error would only be
> 0.02 in that case.  It is true though that one of the two conditional
> probabilities would not be good.


I forgot to mention that for my data, overall classification error is
non-significant. I am only interested in precision/recall for rare outcome.

nitin

>
> > Frank
>
> --
> Frank E Harrell Jr   Professor and Chair           School of Medicine
>                       Department of Biostatistics   Vanderbilt University
>

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