Quality of diverse types of projects is often very difficult to evaluate. Teachers are often ambiguous in the criteria used. The teacher decides the criteria for a passing grade or credit. Advantages Students are more relaxed and less anxious. Students are more free to take risks and explore.
Some students learn more.
Disadvantages Both students and instructors may do less work. It is easy to slight such a course when others are taken under traditional grading. These courses often cannot be counted toward a major, concentration, etc. The teacher decides and announces to the class at the beginning that anyone who does the required amount of work will receive the blanket grade. At this point the scheme tends to become a group contract grading system.