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From Ted Dunning <ted.dunn...@gmail.com>
Subject Re: What does percentCorrect of CrossFloderLearner mean?
Date Wed, 01 Jun 2011 01:47:47 GMT
Yes.

0 is perfect prediction.  It can only be achieved by a score of 1 for the
correct answer every time.

Note that average log-likelihood only works for probability scores.

On Tue, May 31, 2011 at 6:38 PM, Xiaobo Gu <guxiaobo1982@gmail.com> wrote:

> On Tue, May 31, 2011 at 11:54 PM, Ted Dunning <ted.dunning@gmail.com>
> wrote:
> > Argh....
> >
> > log-likelihood should approach the percentage of INcorrect answers
> > (negated).
>
> Then we just only to see if the average log likeliyhood is closer to 0
> to determine the perfmonce of the model, regardless the relationship
> between it and percentage of INcorrect or correct answers?
>
>
> > On Tue, May 31, 2011 at 7:49 AM, Xiaobo Gu <guxiaobo1982@gmail.com>
> wrote:
> >
> >> Page 228 of version 7 of Mahout in Action says :
> >>
> >> Log-likelihood has a maximum value of zero and no bound on how far
> >> negative it can go. For highly accurate classifiers, the value of
> >> average log-likelihood should be close to the average percent correct
> >> for the classifier times the number of target categories.
> >>
> >> Average percent correct times the number of target categories is more
> >> than 0, while Log-likelihood is always less than 0, then is the above
> >> statement correct ?
> >>
> >>
> >>
> >> On Tue, May 31, 2011 at 10:45 PM, Xiaobo Gu <guxiaobo1982@gmail.com>
> >> wrote:
> >> > Does it mean the percent of records that the model has correctlly
> >> > predicted the target on the validate protion of the data set, then it
> >> > should be between 0 and 1, and the bigger the better performance of
> >> > the model ?
> >> >
> >> > Regards,
> >> >
> >> > Xiaobo Gu
> >> >
> >>
> >
>

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