[R] how to use the randomForest and rpart function?

Tim Howard tghoward at gw.dec.state.ny.us
Thu Mar 9 13:39:01 CET 2006


Michael - 
I recall reading something Breiman wrote that said essentially "don't skimp on the number of trees - they are cheap to build and it makes for a better model."  Also, look at your error rates (using plot), and make sure you run enough trees so that the error settles down. You'll likely be building 1000 or so trees. 

Tim


************
>Hi Andy,

Does the randomForest have a Cross Validation built-in to decide what is the
best number of trees or I have to find the best number manually by myself?

Thanks a lot!

Michael.

On 3/7/06, Liaw, Andy <andy_liaw at merck.com> wrote:
>
> Yes, I do know.  That's why I pointed you to the reference linked from the
> help page.
>
> BTW, there's also an R News article describing the initial version of the
> package.  Have you perused that?
>
> Andy




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