Index: trunk/autoquest-core-usability/src/main/java/de/ugoe/cs/autoquest/usability/CommonTaskRateRule.java
===================================================================
--- trunk/autoquest-core-usability/src/main/java/de/ugoe/cs/autoquest/usability/CommonTaskRateRule.java	(revision 1950)
+++ trunk/autoquest-core-usability/src/main/java/de/ugoe/cs/autoquest/usability/CommonTaskRateRule.java	(revision 1959)
@@ -61,5 +61,6 @@
                                    UsabilityEvaluationResult results)
     {
-        // the mean should tend to 0.1 (all subsequent 10 actions are covered by the same task).
+        // the mean indicates how many different root nodes 10 subsequent actions have.
+        // The mean should tend to 0.1 (all subsequent 10 actions are covered by the same root task).
         // The ratio must be similar, i.e., if the mean is 0.1 the ratio is 0, if the mean is 1.0
         // the ratio is 1000
@@ -91,4 +92,6 @@
         final List<IEventTaskInstance> leafNodes = new ArrayList<>();
         
+        // determine for always 10 subsequent actions the root tasks performed for them.
+        // then determine, the ratio of different root tasks to 10.
         for (IUserSession session : sessions) {
             rootNodes.clear();