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Copyright © 2010 SAS Institute Inc. All rights reserved.
Decision Trees Using SAS
Sylvain Tremblay
SAS Canada – Education
SAS Halifax Regional User GroupApril 29, 2011
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Copyright © 2010, SAS Institute Inc. All rights reserved.
Agenda
What is a decision tree?
Decision trees using SAS Enterprise Miner
Decision trees using JMP
Conclusion / Questions
5
Copyright © 2010, SAS Institute Inc. All rights reserved.
A Decision Tree is
A predictive model
A representation of the relationship between a target (dependant variable) and a set of inputs (independant variables)
A supervised learning method
A recursive partitionning algorithm
Also know by the name of algorithms that were commercialized:
CART (Classification And Regression Tree)
CHAID (CHi-squared Automatic Interaction Detector)
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Copyright © 2010, SAS Institute Inc. All rights reserved.
Simple Prediction Illustration
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Predict P(Y=1| X1, X2)
Training Data
...
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Copyright © 2010, SAS Institute Inc. All rights reserved.
Decision Tree Split Search
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0.63
x2<0.63 ≥0.63
Create a partition rule from the best partition across all inputs.
...
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Copyright © 2010, SAS Institute Inc. All rights reserved.
Decision Tree Prediction Rules
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60%55%
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<0.52 ≥0.52 <0.51 ≥0.51x1
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<0.63 ≥0.63
root node
interior node
leaf node
...
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Copyright © 2010, SAS Institute Inc. All rights reserved.
Decision Tree Prediction Rules
40%
60%55%
x1
<0.52 ≥0.52 ≥0.51
<0.63
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Decision = Estimate = 0.70
70%
<0.51x1
x2
≥0.63
Predict:Predict:
...
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Copyright © 2010, SAS Institute Inc. All rights reserved.
Agenda
What is a decision tree?
Decision trees using SAS Enterprise Miner
Decision trees using JMP
Conclusion / Questions
11
Copyright © 2010, SAS Institute Inc. All rights reserved.
Decision Trees with SAS Enterprise Miner
Trees can be created manually or automatically
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Copyright © 2010, SAS Institute Inc. All rights reserved.
Decision Trees with SAS Enterprise Minermanually
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Copyright © 2010, SAS Institute Inc. All rights reserved.
Decision Trees with SAS Enterprise Minermanually
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Copyright © 2010, SAS Institute Inc. All rights reserved.
Decision Trees with SAS Enterprise Minermanually
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Copyright © 2010, SAS Institute Inc. All rights reserved.
Decision Trees with SAS Enterprise Minerautomatically
EM Tree Parameters
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Copyright © 2010, SAS Institute Inc. All rights reserved.
Agenda
What is a decision tree?
Decision trees using SAS Enterprise Miner
Decision trees using JMP
Conclusion / Questions
20
Copyright © 2010, SAS Institute Inc. All rights reserved.
Agenda
What is a decision tree?
Decision trees using SAS Enterprise Miner
Decision trees using JMP
Conclusion / Questions