Optimize Threshold
Synopsis
This operator evaluates different thresholds and delivers a model with the best threshold attached.
Description
When solving a classification task one derives confidences for each class. By default, RapidMiner assigns the prediction to the class with the highest confidence. In a binominal classification case this yields to the fact, that you assign the prediction to the class which has more than 0.5 confidence of being correct. This operator automatically changes this threshold to get the threshold which results in the highest accuracy.
Input
exa
The ExampleSet you want the thresholds to be optimized on.
mod
The model for scoring. It is not mandatory to provide a model, but recommended to get a GroupedModel as result. If you do not have a model provided your provided ExampleSet needs to be scored already.
Output
exa
The scored example set with the best thresholds applied.
mod
If you provide a model as an input, you will receive a GroupedModel with the original Model and the Threshold Model combined. You can use this to score new data and apply the threshold at the same time. If you do not provide a model you will only get the threshold model. This threshold model can be applied using Apply Model.
per
The performance of the best threshold.