Thanks Liaw! I just implemented it using tapply: tapply(fit$splits[, "improve"], rownames(fit$splits), sum)
If you can reference me to any other source / example and so on - it would be great. but either way - you helped me a lot, thank you ! 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) ---------------------------------------------------------------------------------------------- On Mon, Mar 8, 2010 at 4:52 PM, Liaw, Andy <andy_l...@merck.com> wrote: > One way to do it (no p-values) is explained in the original CART book. > You basically add up all the "improvement" (in fit$split[, "improve"]) > due to each splitting variable. > > Andy > > From: Tal Galili > > > > Simple example: > > > > # Classification Tree with rpart > > > > library(rpart) > > > > # grow tree > > > > fit <- rpart(Kyphosis ~ Age + Number + Start, > > > > method="class", data=kyphosis) > > > > Now I would like to know how can I measure the "importance" > > of each of my > > three explanatory variables (Age, Number, Start) in the model? > > > > If this was a regression model, I could have looked at p > > values from the > > "anova" F test (between lm models with and without the > > variable). But what > > is the equivalence of using "anova" on lm to an rpart object ? > > > > Any pointers, insights and references to this question will > > be helpful. > > > > 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 attach...{{dropped:15}} ______________________________________________ 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.
