On the Effect of Class Size on the Evaluation of Lecturers' Performance

In various universities, the evaluation of lecturers by their students is based on questionnaires.The final grade of a lecturer is obtained as a weighted average of questions averaged over all questionnaires of the class.The lecturers with the highest averages are declared as the best.The purpose of this note is to point out the effect of the number of questionnaires on the average grade.We show by a heuristic argument that lecturers of large classes have a smaller chance of being elected best, as compared with equivalent lecturers of smaller classes.