explain ROC graph

Dhiii12

Help me,

can anyone explain about this ROC graph on rapidminer, I'm just learning? how to get the AUC 7.511 value on this ROC chart

Thank you for your time and help!

dhiya

BalazsBarany

Hi!

ROC (Receiver Operator Characteristics) charts are described in the help of the Compare ROCs operator.
https://docs.rapidminer.com/latest/studio/operators/validation/visual/compare_rocs.html

For drawing this chart, the predictions are sorted descending by confidence. At each confidence level, the red line goes up for every correct prediction and to the right for every wrong prediction. The ideal "curve" would always go up because every decision would be right with a 100 % confidence. 

The Area Under the Curve is calculated by literally determining the area under the red curve. It can be 1 as the maximum (the area of a square going from (0, 0) to (1, 1) and theoretically 0 as the minimum. 0.5 is like tossing coins: Random true or false results.

Regards,
Balázs

BalazsBarany

Hi!

ROC (Receiver Operator Characteristics) charts are described in the help of the Compare ROCs operator.
https://docs.rapidminer.com/latest/studio/operators/validation/visual/compare_rocs.html

For drawing this chart, the predictions are sorted descending by confidence. At each confidence level, the red line goes up for every correct prediction and to the right for every wrong prediction. The ideal "curve" would always go up because every decision would be right with a 100 % confidence. 

The Area Under the Curve is calculated by literally determining the area under the red curve. It can be 1 as the maximum (the area of a square going from (0, 0) to (1, 1) and theoretically 0 as the minimum. 0.5 is like tossing coins: Random true or false results.

Regards,
Balázs

Dhiii12

Hello @BalazsBarany

thanks for the answer it was very helpful
@BalazsBarany

Dhiii12

two question please, 

what is the difference between blue line and red line, 

what is the shadow blue and red behind the line?

Thank you for your time and help!

@BalazsBarany

BalazsBarany

Hi!

As you can see in the charts, the blue line is called "ROC (Thresholds)". These are the confidence levels as described.

The areas are the variance resulting from cross validation iterations.

Regards,
Balázs