Grading Comparisons

Some kind of comparison is being made when grades are assigned. For example, an instructor may compare a student's performance to that of his or her classmates, to standards of excellence (i.e., predetermined objectives, contracts, professional standards) or to combinations of each. Four common comparisons used to determine college and university grades and the major advantages and disadvantages of each are discussed in the following section.

Comparisons with other students

By comparing a student's overall course performance with that of some relevant group of students, the instructor assigns a grade to show the student's level of achievement or standing within that group. An "A" might not represent excellence in attainment of knowledge and skill if the reference group as a whole is somewhat inept. All students enrolled in a course during a given semester or all students enrolled in a course since its inception are examples of possible comparison groups. The nature of the reference group used is the key to interpreting grades based on comparisons with other students.

Some advantages of grading based on comparison with other students

  1. Individuals whose academic performance is outstanding in comparison to their peers are rewarded.
  2. The system is a common one that many faculty members are familiar with. Given additional information about the students, instructor, or college department, grades from the system can be interpreted easily.

Some disadvantages of grading based on comparison with other students

  1. No matter how outstanding the reference group of students is, some will receive low grades; no matter how low the overall achievement in the reference group, some students will receive high grades. Grades are difficult to interpret without additional information about the overall quality of the group.
  2. Grading standards in a course tend to fluctuate with the quality of each class of students. Standards are raised by the performance of a bright class and lowered by the performance of a less able group of students. Often a student's grade depends on who was in the class.
  3. There is usually a need to develop course "norms" which account for more than a single class performance. Students of an instructor who is new to the course may be at a particular disadvantage since the reference group will necessarily be small and very possibly atypical compared with future classes.

Comparisons with established standards

Grades may be obtained by comparing a student's performance with specified absolute standards rather than with such relative standards as the work of other students. In this grading method, the instructor is interested in indicating how much of a set of tasks or ideas a student knows, rather than how many other students have mastered more or less of that domain. A "C" in an introductory statistics class might indicate that the student has minimal knowledge of descriptive and inferential statistics. A much higher achievement level would be required for an "A." Note that students' grades depend on their level of content mastery; thus the levels of performance of their classmates has no bearing on the final course grade. There are no quotas in each grade category. It is possible in a given class that all students could receive an "A" or a "B."

Some advantages of grading based on comparison to absolute standards

  1. Course goals and standards must necessarily be defined clearly and communicated to the students.
  2. Most students, if they work hard enough and receive adequate instruction, can obtain high grades. The focus is on achieving course goals, not on competing for a grade.
  3. Final course grades reflect achievement of course goals. The grade indicates what a student knows rather than how well he or she has performed relative to the reference group.
  4. Students do not jeopardize their own grade if they help another student with course work.

Some disadvantages of grading based on comparison to absolute standards

  1. It is difficult and time consuming to determine what course standards should be for each possible course grade issued.
  2. The instructor has to decide on reasonable expectations of students and necessary prerequisite knowledge for subsequent courses. Inexperienced instructors may be at a disadvantage in making these assessments.
  3. A complete interpretation of the meaning of a course grade cannot be made unless the major course goals are also available.

Comparisons based on learning relative to improvement and ability

The following two comparisons--with improvement and ability--are sometimes used by instructors in grading students. There are such serious philosophical and methodological problems related to these comparisons that their use is highly questionable for most educational situations.

Relative to improvement

Students' grades may be based on the knowledge and skill they possess at the end of a course compared to their level of achievement at the beginning of the course. Large gains are assigned high grades and small gains are represented by low grades. Students who enter a course with some initial knowledge of the material are obviously penalized; they have less to gain from a course than does a relatively naive student. The post test-pretest gain score is more error-laden, from a measurement perspective, than either of the scores from which it is derived. Though growth is certainly important when assessing the impact of instruction, it is less useful as a basis for determining course grades than end-of-course competence. The value of grades which reflect growth in a college-level course is probably minimal.

Relative to ability

Course grades might represent the amount students learned in a course relative to how much they could be expected to learn as predicted from their measured academic ability. Students with high ability scores (e.g., scores on the Scholastic Aptitude Test or American College Test) would be expected to achieve higher final examination scores than those with lower ability scores. When grades are based on comparisons with predicted ability, an "overachiever" and an "underachiever" may receive the same grade in a particular course, yet their levels of competence with respect to the course content may be vastly different. The first student may not be prepared to take a more advanced course, but the second student may be. A course grade may, in part, reflect the amount of effort the instructor believes a student has put into a course. The high ability students who can satisfy course requirements with minimal effort are penalized for their apparent lack of effort. Since the letter grade alone does not communicate such information, the value of ability-based grading does not warrant its use.


A single course grade should represent only one of the several grading comparisons noted above. To expect a course grade to reflect more than one of these comparisons is too much of a communication burden. Instructors who wish to communicate more than relative group standing, or subject matter competence or level of effort, must find additional ways to provide such information to each student.