R help - Apr 2010 - Question on: Random Forest Variable Importance for Regression Problems

I am trying to use the package RandomForest performing regression.
The variable importance estimates are given as:  "%IncMSE"     and
"IncNodePurity"
Can anyone explain me what these refer to and how they are calculated?
I found a lot of information on variable importance measures for 
classification problems, but nothing on regression.

Thanks a lot.
Mareike

I would have thought that the help page for importance() is an (the?) obvious
place to look...

If that description is not clear, please let me know which part isn't clear
to you.

Andy

From: Mareike Lies
> 
> I am trying to use the package RandomForest performing regression.
> The variable importance estimates are given as:  "%IncMSE"    
>  and      
> "IncNodePurity"
> Can anyone explain me what these refer to and how they are calculated?
> I found a lot of information on variable importance measures for 
> classification problems, but nothing on regression.
> 
> Thanks a lot.
> Mareike
> 
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