what is the usage of parameter “confidence” in operator “Decision Tree”？

Answers

• yyhuang RM Data Scientist

  April 2021 edited April 2021

  Hi @lg21c,
  
  Not sure about the definition of f and q in your probability function. But you can refer to the source code of decision tree and pessimisticpruner.java scripts here
  https://github.com/rapidminer/rapidminer-studio-modular/blob/master/rapidminer-studio-core/src/main/java/com/rapidminer/operator/learner/tree/DecisionTreeLearner.java
  
  https://github.com/rapidminer/rapidminer-studio-modular/blob/master/rapidminer-studio-core/src/main/java/com/rapidminer/operator/learner/tree/PessimisticPruner.java
  
  If the tree grows too big, the model is easily overfitting. The confidence level is used to determine whether or not prune the branches based on pessimistic errors.
  
  
  
  HTH!
  
  YY

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• lg21c Contributor II

  April 2021

  Hi @yyhuang , it would be a lot easier for people to know the complex parameters if rapidminer company provide detailed technical manual，many users can't read java
  

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• lg21c Contributor II

  April 2021

  The formula in the program is complicated，I just want to know
  
  
  

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• yyhuang RM Data Scientist

  April 2021

  This operator for decision tree is the same as Quinlan's C4.5 or CART depending on the criterion, e.g. using gain_ratio or Gini.
  Useful reference
  Quinlan,J.R.: C4.5: Programs for Machine Learning Morgan Kauffman, 1993
  

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