A group of 20 preservice teachers who just completed their studentteaching internships was posed with the following situation (which was bound to be poignantly realistic for at least some of them): Suppose that in the course of student teaching, you taught a unit of study that you developed yourself, working long and hard on it. It represented your best work and you thought that it would be effective, engaging, and intelli-gent. You expected your students to enjoy the material and to learn a great deal because you were introducing them to wonderful new ideas and useful skills. Unfortunately, when you calculated student grades for the unit following the final assessment, you found that most of the students not only received low scores, but also clearly failed to grasp the material. Whom would you blame for the many failures?