Course evaluation is often a big waste of time.
Here is an idea for making evaluations more useful by Dale Roy, Instructional Development Centre. The information comes too late - usually too long after the course is over and the students have gone. I decided that a better time to ask students how the course was going was about six weeks into the term, early enough to make subtle changes in the course. In the first six weeks, I try for variety in how I teach. The evaluation consists of asking students to consider which kind of teaching they have found most helpful and the kind they have found least helpful.