Terry Therneau
2011-Jan-11 13:55 UTC
[R] Some questions concerning survival tree analysis using the rpart module
All the documentation that I have on survival splitting is found in the technical report you mention. However, there is both a short form and a long form of this on our web site, did you get the larger one (52 pages)? I admit it is not a lot. There are no other split algorithms implimented for survival data. It would be possible to add your own. Attached is a slightly updated version of the technical report that has a section on user written split rules. The pruning method is based on cost-compexity. It is one area where substantial improvment may be possible. I thought a lot about this at one time, but it's now been a decade since I put any intellectual energy into rpart. Terry Therneau ------begin included message ---- I succeeded in performing survival tree analysis using the ?method=exp? function, and by defining a ?Surv object?. However, I wonder what kind of splitting algorithm and pruning method are used by R to obtain the survival tree. I know that for classification trees, it is possible to specify the split algorithm using the function ?parms=list(split=?)?, which can be specified as ?gini? or ?info?. Are there also multiple options for the splitting algorithm using the ?Exp? method for survival trees, that can be defined or is there only one default option? Is the pruning method for the survival tree in the rpart package also based on tree cost complexity? I have read the report ?An introduction to recursive partitioning using the rpart routines? that you have written. It was really helpful in familiarizing myself with CART analysis using the rpart package. However, I missed some detail on the background of survival tree analysis (using rpart and in general). Do you know whether there is another document or book that elaborates more on this subject? --end inclusion ---- -------------- next part -------------- A non-text attachment was scrubbed... Name: zed.pdf Type: application/pdf Size: 356858 bytes Desc: not available URL: <https://stat.ethz.ch/pipermail/r-help/attachments/20110111/05710d10/attachment.pdf>