Nowadays， it has become as common in colleges and universities for students to grade teachers as for teachers to grade students. In some universities students' rating has even become the only source of information on teaching effectiveness.。
This， however， has caused great controversy. Some are in favor of the rating system， They hold that since students attend the teachers' classes every day， they should have their opinion about their teachers' effectiveness. Others， on the contrary， are strongly against it. They believe that there is much more to teaching than what is shown on students' rating forms. Students should not be expected to judge whether the materials they use are up to date or how well the teacher knows about the subject. These judgments require professional knowledge， which is best left for the teachers' colleagues.
I think students' rating of their teachers is necessary， but it should be conducted in a way that can really shed meaningful light on teachers' performance. Instead of rating the teachers' knowledge on the subject， students should be asked to estimate what they have learned in a course， and to report on such things as a teacher's ability to communicate with students， his or her relationship with students， and his or her ability to arouse students' interest in the subject.
