CostsensitiveClassifier and ThresholdSelector

classic Classic list List threaded Threaded
3 messages Options
Reply | Threaded
Open this post in threaded view
|

CostsensitiveClassifier and ThresholdSelector

Fer137
For the same data set is Costsensitiveclassifier equivalent to some
Thresholdselector in a certain manual probability? Or the cost calculation
is more complex than assigning that probability to the class?



--
Sent from: https://weka.8497.n7.nabble.com/
_______________________________________________
Wekalist mailing list -- [hidden email]
Send posts to: To unsubscribe send an email to [hidden email]
To subscribe, unsubscribe, etc., visit
https://list.waikato.ac.nz/postorius/lists/wekalist.list.waikato.ac.nz
List etiquette: http://www.cs.waikato.ac.nz/~ml/weka/mailinglist_etiquette.html
Reply | Threaded
Open this post in threaded view
|

Re: CostsensitiveClassifier and ThresholdSelector

Eibe Frank-2
Administrator
The following assumes that you have switched CostSensitiveClassifier to the minimum expected cost approach, which simply adjust predictions made by the base classifier, based on the costs provided, and does not adjust the training process used for constructing the base classifier. By default, CostSensitiveClassifier will reweight the training data based on the costs provided. The base classifier will then of course be different from the one used in ThresholdSelector.

If you restrict consideration to two-class problems and you consider pure classification only (i.e., no probability estimation), then, yes, you should be able to find a threshold in ThresholdSelector that gives you the same classifications as CostSensitiveClassifier with a particular cost matrix. (Of course, this also assumes that your cost matrix does not specify instance-specific costs.)

Cheers,
Eibe

On Sun, Jan 26, 2020 at 7:58 PM Fer137 <[hidden email]> wrote:
For the same data set is Costsensitiveclassifier equivalent to some
Thresholdselector in a certain manual probability? Or the cost calculation
is more complex than assigning that probability to the class?



--
Sent from: https://weka.8497.n7.nabble.com/
_______________________________________________
Wekalist mailing list -- [hidden email]
Send posts to: To unsubscribe send an email to [hidden email]
To subscribe, unsubscribe, etc., visit
https://list.waikato.ac.nz/postorius/lists/wekalist.list.waikato.ac.nz
List etiquette: http://www.cs.waikato.ac.nz/~ml/weka/mailinglist_etiquette.html

_______________________________________________
Wekalist mailing list -- [hidden email]
Send posts to: To unsubscribe send an email to [hidden email]
To subscribe, unsubscribe, etc., visit
https://list.waikato.ac.nz/postorius/lists/wekalist.list.waikato.ac.nz
List etiquette: http://www.cs.waikato.ac.nz/~ml/weka/mailinglist_etiquette.html
Reply | Threaded
Open this post in threaded view
|

Re: CostsensitiveClassifier and ThresholdSelector

Fer137
Thank you very much.



--
Sent from: https://weka.8497.n7.nabble.com/
_______________________________________________
Wekalist mailing list -- [hidden email]
Send posts to: To unsubscribe send an email to [hidden email]
To subscribe, unsubscribe, etc., visit
https://list.waikato.ac.nz/postorius/lists/wekalist.list.waikato.ac.nz
List etiquette: http://www.cs.waikato.ac.nz/~ml/weka/mailinglist_etiquette.html