Students confidentially comment on and grade each other's papers. This offers them a chance to think critically about what makes a good paper. Students submit their first draft of their term paper (topics vary). Each student is given four or five term papers to grade and comment on. Students are told that, independently of their submission of grades, they can offer whatever constructive criticism they like to their fellow students. These grades are given to the instructor and are not communicated to the writers of the papers and have no impact on the writers' grades. The aim is to get each student to see a range of papers and consider which succeed and why. The students then submit a revised version of their own paper which is graded.
The instructor reports that students find this exercise useful, and that it potentially improves the average quality of papers.