by Thanh-Van (Vicky) Nguyen, Pharm.D., PGY 1 Pharmacy
Practice Resident, Kaiser Permanente Mid-Atlantic
When students hear
the terms “curve” and “grades” used together in a sentence, they automatically assume
that grades will be scaled upwards. In
fact, this is not always the case. The act
of scoring on a curve has been performed for years and is commonplace in higher
education, particularly in science curricula.
However, grading on the curve has multiple meanings and, as with all
other practices, there are pros and cons to grading on a curve.
Typically, curving
an exam is achieved by adding points to everyone’s score in order to shift the
average upward. The score of the
student(s) who performed the best on the exam is boosted to 100% and then the other
exam scores are scaled up by a similar amount.
This consequently boosts all scores on the exam and often translates
into higher grades for everyone. If the
procedure is rarely performed and students are not accustomed to curving,
students wouldn’t anticipate receiving addition points and will likely put
effort into studying. But when curving
becomes routine, potential pitfalls may occur.
Students may become less motivated to perform at their best if they know
that they will automatically receive additional points. The question then becomes whether or not curving
grades accurately reflects knowledge and performance. By curving grades, are we merely boosting students’ egos only to send them off into the world less prepared? Does it create a false sense of security?
There are certain
circumstances that may warrant curving exam scores. For example, when creating exams, professors
may misjudge the difficulty or clarity of their questions. In these instances, it is simply unfair to
punish students with point deductions due to poorly written questions. In other situations, the subject matter may
not have been taught well, resulting in poor student performance. When the decision is made to curve scores for
these reasons, its important to resolve the underlying problem. This can be as simple as rewording future
exam questions, modifying one’s teaching method, or providing additional
instruction. Unfortunately, some instructors
move forward without conducting a root cause analysis or taking any corrective
action.
Some proponents
argue that curving can prevent grade inflation and ensures that grades are
appropriately distributed among students.
In one form of curving, instructors assign grades based on a normal
distribution. The grades are distributed
such that students who score near the average receive a high C or a low B. Students above the mean would receive an A or
B. Students below the mean would receive
a C or D. Outliers are assigned an F. This form of curving exists but it’s rarely
used. Assigning an “F” to someone who
scored 82% on an exam where the class average was 93% would likely be met with
outrage. This method of curving
penalizes students for not performing as well as their peers – even when they
demonstrate reasonably good mastery of the material.
The procedures used
to curve scores are not standardized and practices vary among professors and
institutions. Some professors review exam
questions and curve based on the number of questions where a substantial portion
of students got the answer incorrect.
Other professors simply bump the highest grade up to 100% and scale the
rest by a similar amount. Whether all
scores should be curved across the board is another aspect to consider. Curving can also be done selectively to help boost a few students’ scores or to reduce the number of students
who fail. This practice calls into
questions fairness and smacks of favoritism.
Regardless, there is a lack of consensus regarding the best method of
curving. There comes a
point when curving no longer accurately represents student learning but rather
a manipulation of numbers.
There is a time and
place when curving grades may be appropriate but the practice should not be commonplace. When curving scores becomes
a routine practice, it’s time to re-evaluate the teaching and evaluation
methods.
References
1. Kulick G, Wright R. The Impact of Grading on a Curve:
A Simulation Analysis.
International Journal for the Scholarship of Teaching and Learning.
2008;2(2):1-17.
2. Bradley B. To Curve or Not to Curve:
Norm-referenced Grading vs. Criterion-referenced Grading. Focus on Faculty. 2005:3-4.
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