Retention Rate

I wonder about the retention rate of students for fixed-term classes, i.e. the breakdown of number of students who sign-up, who actually start the course, and who complete the course.  The behavior of students in this matter obviously impacts the sustainability and revenue model of MOOC offerings (though I hope they can remain free to most students!).

The one class I haven't able to complete so far has been Martin Odersky's Functional Programming Principles in Scala on Coursera.  There were a few reasons, like the fact that I started a few weeks late, but it ultimately boils down to the fact that functional programming isn't at the top of my current priority queue.

Part of the beauty of free courses, of course, is that the only cost of walking away is the opportunity cost.  Free to come and go -- Udacity seems to embrace this principle the most.