Hi All, I am fitting a tree to censored survival data using the rpart package and wanted to better understand the results.
I am trying to interpret the output from the tree. I am interested in understanding what "yval" is for a survival tree. I see in the output of summary, the phrase "estimated rate". The estimated rate is 1 for the entire tree, and more of less for each node. So, I am guessing it is some function of the event rate in each node compared to the full tree. But then I saw a node with no events a non-null estimated rate, that is a little confusing. I have the document called "An Introduction to Recursive Partitioning Using the RPART Routines", while it does mention "exponential scaling", the explanation rather brief. I will be very grateful if someone could guide me to some more documentation. Here is some reproducible code: library(rpart) bladder1 <- bladder[bladder$enum < 5, ] fit <- rpart(Surv(stop, event) ~ rx + size + number, bladder1) print(fit) summary(fit) plot(fit, uniform=T, branch=.4, compress=T) text(fit, use.n=T) Here is an excerpt from summary(fit): Node number 56: 8 observations events=0, estimated rate=0.1858292 , mean deviance=0.2035427 Thanks in advance, Ritwik > R.Version() $platform [1] "i386-pc-mingw32" $arch [1] "i386" $os [1] "mingw32" $system [1] "i386, mingw32" $status [1] "" $major [1] "2" $minor [1] "10.0" $year [1] "2009" $month [1] "10" $day [1] "26" $`svn rev` [1] "50208" $language [1] "R" $version.string [1] "R version 2.10.0 (2009-10-26)" -- Ritwik Sinha ritwik.si...@gmail.com | +12038160799 | http://ritwik.sinha.googlepages.com/ [[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.
