Message-ID: <dae9a2a60904100828n35771262q3fc4c5d27387164e@mail.gmail.com>
Date: 2009-04-10T15:28:01Z
From: Dimitri Liakhovitski
Subject: Random Forests: Question about R^2
Dear Random Forests gurus,
I have a question about R^2 provided by randomForest (for regression).
I don't succeed in finding this information.
In the help file for randomForest under "Value" it says:
rsq: (regression only) - "pseudo R-squared'': 1 - mse / Var(y).
Could someone please explain in somewhat more detail how exactly R^2
is calculated?
Is "mse" mean squared error for prediction?
Is "mse" an average of mse's for all trees run on out-of-bag holdout samples?
In other words - is this R^2 based on out-of-bag samples?
Thank you very much for clarification!
--
Dimitri Liakhovitski
MarketTools, Inc.
Dimitri.Liakhovitski at markettools.com