Meaning of "TRUE" column in R RandomForest output for Importance()?
I don't see any columns like that. Here's a simple example:

library(randomForest)
data(iris)
iris.rf &lt;- randomForest(Species ~ ., data=iris, importance=TRUE)
colnames(importance(iris.rf))

# [1] "setosa"               "versicolor"          
# [3] "virginica"            "MeanDecreaseAccuracy"
# [5] "MeanDecreaseGini" 


If you're seeing columns named "TRUE" and "FALSE" in the matrix returned by importance, my best guess is that those are the names of columns in your training data.