Extra Credit can often be used to allow students to compensate for their performance on other assignments. Know that if used liberally, extra credit can become an expectation among students.
Curving grades can be harmful to learning overall. By curving student grades, teachers suggest that "grades, and the learning they supposedly represent, are a limited commodity dispensed by the teacher according to a statistical formula." Curving grades can facilitate competition among students, which can be destructive to the learning process.