Cost Sensitive Classification Walkthrough
- Open Weka as normal and go to the "Classify" tab.
- Instead of choosing J48 (or any of the standard learners) choose "CostSensitiveClassifier"
under the "meta" category.
- Open the classifier's options like any other learner
- Use the "Choose" button to pick the learner you wish to use (eg
- Next, click where it says "1 x 1 Cost Matrix", this will open a
new window where you can edit the cost matrix.
- Change the number of classes to 2, and change the costs of type 1 and type
2 errors. You must press <enter> after typing values in these
boxes for the tool to record the changes.
- Close the cost matrix editor, close the CostSensitiveClassifier options by
clicking "OK" then run the tool.
- Vary the cost ratio by repeating steps 5 through 7 as required by the