Check out caret::varImp.rpart(). It's described in the original CART book.
Andy From: Tal Galili > > Hello all, > > When building a CART model (specifically classification tree) > using rpart, > it is sometimes interesting to know what is the importance of > the various > variables introduced to the model. > > Thus, my question is: *What common measures exists for > ranking/measuring > variable importance of participating variables in a CART > model? And how can > this be computed using R (for example, when using the rpart package)* > > For example, here is some dummy code, created so you might show your > solutions on it. This example is structured so that it is clear that > variable x1 and x2 are "important" while (in some sense) x1 is more > important then x2 (since x1 should apply to more cases, thus make more > influence on the structure of the data, then x2). > > set.seed(31431) > > n <- 400 > > x1 <- rnorm(n) > > x2 <- rnorm(n) > > x3 <- rnorm(n) > > x4 <- rnorm(n) > > x5 <- rnorm(n) > > X <- data.frame(x1,x2,x3,x4,x5) > > y <- sample(letters[1:4], n, T) > > y <- ifelse(X[,2] < -1 , "b", y) > > y <- ifelse(X[,1] < 0 , "a", y) > > require(rpart) > > fit <- rpart(y~., X) > > plot(fit); text(fit) > > info.gain.rpart(fit) # your function - telling us on each variable how > important it is > > (references are always welcomed) > > > Thanks! > > Tal > > ----------------Contact > Details:------------------------------------------------------- > Contact me: tal.gal...@gmail.com | 972-52-7275845 > Read me: www.talgalili.com (Hebrew) | www.biostatistics.co.il > (Hebrew) | > www.r-statistics.com (English) > -------------------------------------------------------------- > -------------------------------- > > [[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. > Notice: This e-mail message, together with any attachme...{{dropped:11}} ______________________________________________ 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.