diff --git a/config.tutorial.yaml b/config.tutorial.yaml
index 31ca7f99..edf0091c 100755
--- a/config.tutorial.yaml
+++ b/config.tutorial.yaml
@@ -31,7 +31,7 @@ clustering:
       committable: any
       ramp_limit_up: max
       ramp_limit_down: max
-      efficiency:mean
+      efficiency: mean
 
 snapshots:
   start: "2013-03-01"