A survey of faculty and students at Harvard Business school found that what engages students most in a case is that it tell a story: “a good case presents an interestprovoking issue and promotes empathy with the central characters. It delineates their individual perspectives and personal circumstances well enough to enable students to understand the characters’ experience of the issue. The importance of the compelling issue and the empathetic character reflects the fact that cases typically focus on the intersection between organizational or situational dynamics and individual perception, judgment, and action” (Boehrer and Linsky, 1990).
Speaking of Teaching, Stanford University Newsletter on Teaching. Winter 1994, Vol. 5, No. 2 Teaching with Case Studies (pdf)