Hello, If you do
my.tree <- rpart(cancel ~ experience) and then you check my.tree$frame you will note that the complexity parameter there is 0. Check ?rpart.object to get a description of what this output means. But essentially, you will not be able to break the leaf unless you set a complexity parameter below that value, this is, never. You may need to go into the internals of the function (and the C code) in order to understand how this parameter is calculated. It looks to me as an oddity and it is worth trying to understand why. Best regards, Carlos J. Gil Bellosta http://www.datanalytics.com P.S.: Note that there is a bug in your submitted code that requires some hand fixing. On Sun, 2009-07-26 at 11:37 -0700, Robert Smith wrote: > Hi, > > I am using rpart decision trees to analyze customer churn. I am finding that > the decision trees created are not effective because they are not able to > recognize factors that influence churn. I have created an example situation > below. What do I need to do to for rpart to build a tree with the variable > experience? My guess is that this would happen if rpart used the loss matrix > while creating the tree. > > > experience <- as.factor(c(rep("good",90), rep("bad",10))) > > cancel <- as.factor(c(rep("no",85), rep("yes",5), rep("no",5), > rep("yes",5))) > > table(experience, cancel) > cancel > experience no yes > bad 5 5 > good 85 5 > > rpart(cancel ~ experience) > n= 100 > node), split, n, loss, yval, (yprob) > * denotes terminal node > 1) root 100 10 no (0.9000000 0.1000000) * > > I tried the following commands with no success. > rpart(cancel ~ experience, control=rpart.control(cp=.0001)) > rpart(cancel ~ experience, parms=list(split='information')) > rpart(cancel ~ experience, parms=list(split='information'), > control=rpart.control(cp=.0001)) > rpart(cancel ~ experience, parms=list(loss=matrix(c(0,1,10000,0), nrow=2, > ncol=2))) > > Thanks a lot for your help. > > Best regards, > Robert > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
