To find out how useful the student evaluation on a lecture is, an interesting experiment was done many years ago that the researcher found an actor to deliver a lecture that he had no idea about. He only tried to make it sound impressive and confusing. Interestingly, most students, despite being trained scientists from different fields, found that the lecture was great and they had learned from Dr. Fox. The results were so profound that they call it Dr. Fox effect now. A great coverage on this experiment can be found from weirdexperiments.com.