In the framework of an ISO 9001 certification, a permanent evaluation system of an educational programme has been installed. All students evaluate very frequently the quality of courses and seminars. The evaluations are summarized and made public in such a way that they constitute a regular, quantitative teaching appraisal for every professor and teaching assistant. This system has some advantages, but also unexpected disadvantages: it engenders a lot of work; there are interpretation difficulties; it causes some uneasiness among staff members; and, most importantly, it reinforces the student's attitude of non-involvement.