diff --git a/metrics/raf.sh b/metrics/raf.sh
index a3b61790..993656b1 100755
--- a/metrics/raf.sh
+++ b/metrics/raf.sh
@@ -44,4 +44,6 @@ else
     raf=0
 fi
 
-echo "raf ${raf} Relative Age of File (To repository existence)" > "${output}"
+echo "raf ${raf} Relative Age of File (in the entire timeframe of repository existence),
+    where 0.0 means the file was added in the first commit and 1.0 means that
+    the file was added in the last commit" > "${output}"