A few weeks ago I guided a faculty member in how to create a two tiered system for her class.  1 tier of work for all students, and a tier of work for the students who are ahead in the class above and beyond what is required.  The only incentive for going above and beyond is at the end the students don’t need to take a final if they have a 90% in the class.  Along with this the faculty member began allowing mastery based test retaking for failing students.  This all started 4 weeks ago because half way through the semester they were very anxious and aggravated with the drastic varying levels in her class.  Some students were very far ahead, and others very far behind.  4 weeks since implementation and successful students have been doing the extra activities more for their own enjoyment and mental stimulation then the grade, and she is able to now provide more intense assistance to struggling students because she can focus her efforts on them while others go beyond in the higher tier activities.  This is student success in action, and it can start anytime in the semester.