To Curve or Not to Curve Revisited

Yellow traffic signs showing a bell curve and a stylized graph referencing criterion-referenced grading.The practice of normalizing grades, more popularly known as curving, was a subject of an Innovative Instructor post, To Curve or Not to Curve on May 13, 2013. That article discussed both norm-referenced grading (curving) and criterion-referenced grading (not curving). As the practice of curving has become more controversial in recent years, an op-ed piece in this past Sunday’s New York Times caught my eye. In Why We Should Stop Grading Students on a Curve (The New York Times Sunday Review, September 10, 2016), Adam Grant argues that grade deflation, which occurs when teachers use a curve, is more worrisome than grade inflation. First, by limiting the number of students who can excel, other students who may have mastered the course content are unfairly punished. Second, curving creates a “toxic” environment, a “hypercompetitive culture” where one student’s success means another’s failure.

Grant, a professor of psychology at the Wharton School at the University of Pennsylvania, cites evidence that curving is a “disincentive to study.” Taking observations from his work as an organizational psychologist and applying those in his classroom, Grant has found he could both disrupt the culture of cutthroat competition and get students to work together as a team to prepare for exams. Teamwork has numerous advantages in both the classroom and the workplace as Grant details. Another important aspect is “…that one of the best ways to learn something is to teach it.” When students study together for an exam they benefit from each other’s strengths and expertise. Grant details the methods he used in constructing the exams and how his students have leveraged teamwork to improve their scores on course assessments. One device he uses is a Who Wants to Be a Millionaire-type “lifeline” for students taking the final exam. While his particular approaches may not be suitable for your teaching, the article provides food for thought.

Because I am not advocating for one way of grading over another, but rather encouraging instructors to think about why they are taking a particular approach and whether it is the best solution, I’d like to present a counter argument. In praise of grading on a curve by Eugene Volokh appeared in The Washington Post on February 9, 2015. “Eugene Volokh teaches free speech law, religious freedom law, church-state relations law, a First Amendment Amicus Brief Clinic, and tort law, at UCLA School of Law, where he has also often taught copyright law, criminal law, and a seminar on firearms regulation policy.” He counters some of the standard arguments against curving by pointing out that students and exams will vary from year to year making it difficult to draw consistent lines between, say an A- and B+ exam. This may be even more difficult for a less experienced teacher. Volokh also believes in the value of the curve for reducing the pressure to inflate grades. He points out that competing law schools tend to align their curves, making it an accepted practice for law school faculty to curve. As well, he suggests some tweaks to curving that strengthen its application.

As was pointed out in the earlier post, curving is often used in large lecture or lab courses that may have multiple sections and graders, as it provides a way to standardize grades. However, that issue may be resolved by instructing multiple graders how to assign grades based on a rubric. See The Innovative Instructor on creating rubrics and calibrating multiple graders.

Designing effective assessments is another important skill for instructors to learn, and one that can eliminate the need to use curving to adjust grades on a poorly conceived test. A good place to start is Brown University’s Harriet W. Sheridan Center for Teaching and Learning webpages on designing assessments where you will find resources compiled from a number of Teaching and Learning Centers on designing “assessments that promote and measure student learning.”  The topics include: Classroom Assessment and Feedback, Quizzes, Tests and Exams, Homework Assignments and Problem Sets, Writing Assignments, Student Presentations, Group Projects and Presentations, Labs, and Field Work.

Macie Hall, Instructional Designer
Center for Educational Resources

Image Source: © Reid Sczerba, 2013.



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