title: Interpretation of negative value in varImp() of Random Forest
body: <p>I am using <code>randomForest()</code> function from package randomForest. I am trying the understand the output given by the function <code>varImp()</code> of package caret. For few variables it is showing negative values. What does negative value indicate?</p>
  
  <p>Below is the output:</p>
  
  <pre><code>           Overall
  Year        6.7712260
  Month      -2.6684553
  DOW         2.2681865
  City.Group -0.3534247
  Type        1.4049568
  P1          8.5207072
  P2          6.0449333
  P3          5.3579060
  P4          4.1441309
  P5          5.9207454
  P6          7.3744485
  P7          3.6858546
  </code></pre>
  
  <p>Thanks in advance!!.</p>