[R] CART vs. Random Forest

[Andrew Baek]

> One suggestion if making sure you find the 1's is more important than having
> a low overall error rate:  in rpart, you can specify a loss matrix to say
> that certain kinds of errors are more important than others.  In a random
> forest, you can use different voting thresholds for "1-ness" and "0-ness" to
> bias things -- that is, instead of just taking majority vote, you might
> require (for example) 85% of the trees to agree for something to be declared
> in class 0.

If I use loss matrix in "rpart" and different threshold in "RF", how 
can I compare two packages? Well, Andy Liaw told me "classwt" in RF does
not help much. But when I modified priors in rpart, I got totall new 
results. So I thought this should be applied to RF.

Also, I'll appreciate if you tell me how to change the voting threshold in
RF. I couldn't find it in the manual. Thank you.

Andrew


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