Our instituition is lock step. Faculty have a great deal of influence over retention. Another group not mention is a student's peers. What about group assignments, with fixed groups (that rotate over time) with students enhancing a peer's attendance (through phone calls if needed) as well as with one's peers' enthusiasm?

Another common mistake that I have heard is for the instructor to tell the call that “we will not be using the assigned text.” This is usually done after the students have invested substantial capital in obtaining the book. This de-motivates students almost as much as telling students that one has never taught the course before.