--- loncom/interface/statistics/lonproblemstatistics.pm	2013/10/01 17:52:03	1.123
+++ loncom/interface/statistics/lonproblemstatistics.pm	2013/12/30 13:51:37	1.124
@@ -1,6 +1,6 @@
 # The LearningOnline Network with CAPA
 #
-# $Id: lonproblemstatistics.pm,v 1.123 2013/10/01 17:52:03 bisitz Exp $
+# $Id: lonproblemstatistics.pm,v 1.124 2013/12/30 13:51:37 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -283,7 +283,7 @@ my @Fields = (
              sortable  => 'yes',
              graphable => 'yes',
              long_title => 'Degree of Difficulty'.
-                           ' { 1 - ((#YES+#yes) / Tries) }',
+                           ' ~[ 1 - ((#YES+#yes) / Tries) ~]',
              selectable => 'yes',
              defaultselected => 'yes',
            },