A complete description of the grading system should appear in the course syllabus, including the amount of credit for each assignment, how the final grades will be calculated, and the grade equivalents for the final scores. Also, students should perceive the grading system as fair and equitable, rewarding them proportionately for their achievements. From the standpoint of measurement, many different kinds of assignments, spread over the entire semester provide a fairer estimate of student learning than one or two large tests or papers. In relative grading, students are in competition with one another for a limited number of grades in each category, and a student's grade is based on his or her relative position in the class. No grading system is foolproof, for the integrity of any system depends on the teacher's ability to devise valid and reliable measurements of student performance.
Measurement error is therefore the greatest hindrance to effective grading.
Students like relative grading for much the same reason. Although it is true that the larger the class, the more likely that student performance will begin to look something like a normal curve, the assumption that performance is normally distributed is usually unjustified, even in large sections. In the first place, college students are a highly selected group, not representative of the general population with respect to background or intelligence. Forcing students into this scale tends to wreak havoc with their motivation. Typically, the rationale for grade cutoff points is based on tradition rather than on analysis of student performance over time.