Adjusting GPAs: A Statistician’s Effort to Tackle Grade Inflation

February 10, 2014
Physics & Mathematics

Nearly two decades ago, Texas A&M University statistician Valen E. Johnson found himself in the trenches of one of the most contentious fights in higher education: curbing grade inflation — a problem that still persists nationwide, as does Johnson’s interest in finding a solution.

As a professor at Duke University in 1997, Johnson became the face and statistical muscle behind a first-of-its-kind effort to address grade inflation. The plan would have created an adjusted grade-point average (GPA), but it was defeated because of opposition, mostly from faculty members in the humanities and students worried about having lower GPAs.

A recent analysis of 200 colleges and universities published in the Teachers College Record found that 43 percent of all letter grades awarded in 2008 were A’s, compared to 16 percent in 1960. And Harvard’s student paper recently reported that the median grade awarded to undergraduates at the elite school is now an A-.

“I think it’s resulting in something of a reduction in academic standards,” said Johnson, the author of Grade Inflation: A Crisis in College Education, published in 2003 and now in its second printing. “There’s no real incentive for change. The students want higher grades. The faculty — because their promotion, tenure and merit increases are based, to some extent, on student evaluations — know they’re more likely to get better evaluations if they give better grades. And administrators don‘t want to jump in to impose reform.”

Proposal created ‘adjusted GPA’

Johnson, who joined the Texas A&M Statistics faculty in 2012, is a renowned expert in Bayesian statistics, which uses probability distributions to represent uncertainties on all unknown quantities. His involvement in the Duke fight, which attracted national headlines at the time, started when the university’s provost asked Johnson to sit on a committee to examine grade inflation. Johnson requested and received a trove of data from the registrar’s office. It quickly became clear, he said, that different faculty members were using vastly different standards to assign grades. For instance, on aggregate, humanities instructors graded more leniently than social sciences instructors, who graded more leniently than natural sciences instructors.

“So I created a peer-reviewed statistical model that accounted for the differences in grading and came up with an adjusted GPA,” Johnson said. “There was then a semester-long discussion before the dean of undergraduate affairs proposed that the adjusted GPA replace GPA on student transcripts starting the next semester. That was a really bad move. Nobody knew what their adjusted GPA was. Students all thought they were taking easier classes than everybody else, so everyone thought their GPAs would go down, even though the overall average would remain the same.”

Johnson said that five universities had already asked him to compute adjusted GPAs and that he believed, had a powerhouse like Duke taken the first step, the other schools would have followed. But after contentious debate, Duke’s Arts and Sciences Council, which had the final say on the matter, defeated the proposal on a 19-14 vote.

Following the failed effort, the provost gave Johnson $10,000 to further study questions about grades raised by the debate. His research revealed a pair of key findings: Students gravitate toward taking courses offered by instructors they deem to have laxer standards, and they also tend to give better evaluations to instructors who gave them higher grades.

Better grades, better evaluations

As part of his follow-up research, Johnson set up a website where students could see mean grades that instructors had given in the past and course evaluations of instructors left by other students. When students looked at a past course’s mean grade, Johnson received a record of it. He then looked at whose courses those same students signed up for in the spring and examined the relationship between the variables.

“For example, if they looked at three sections of calculus with different instructors, and one instructor graded easier than the other instructors, I could see how much more likely they were to register in the class in which instructors graded more leniently,” Johnson said. “It turns out they were about twice as likely to enroll in a course that was graded with an A-minus average versus a B average after they looked at the course mean grades.”

To study the impact of course grades on student evaluations, Johnson had freshmen fill out evaluations for courses they were currently taking in the fall along with their grade expectations for that course. He then had those same students fill out course evaluations again in the spring for the same course with the knowledge of what they had actually earned in the course.

“That allowed me to look directly at the influence of course grades on student evaluations,” Johnson said. “As you might expect, the effect of either expected course grade or received course grade is very powerful in student evaluations of teaching. If a student was getting a C in a course, he or she was very unlikely to rate the instructor highly. If they were getting an A in the course, they’re more likely to rate the instructor highly. I think this provides quantitative evidence for something most instructors know: If they grade easier, they will tend to get better course evaluations.”


Today, Johnson is circumspect about the Duke effort. In hindsight, he calls it “a disaster.” And if he had it to do over again, he would have recommended a different approach rather than eliminating the current GPA system, which caused apprehension among faculty and students alike. He now recommends keeping the same GPA measure, but perhaps using the adjusted GPA to distinguish students with a special mark or honor so that graduate schools and employers know the student stood out.

To alleviate some of the fear that instructors have of receiving negative student evaluations in response to awarding poorer grades, Johnson said administrators should consider an approach that would eliminate a certain percentage of the instructor’s lowest evaluations. The percentage of evaluations that were eliminated would be tied to the number of lower grades that the instructor assigned.

“At least when students come to argue about grades to try to get them up, the instructor would feel more comfortable in holding the line, so that incentive would disappear,” Johnson said.

Johnson noted efforts to include the average or median grade for a course alongside the actual grade earned haven’t helped correct grade inflation when tried at other universities. While well intentioned, he said such measures have merely given students a new mechanism to figure out how to find the most lenient instructors. In addition, Johnson said, such a move actually could put the affected students at a disadvantage when potential employers compare them with students from other universities that don’t have such requirements.

To learn more about Johnson, his research into grade inflation and his applications of statistics to solve an eclectic range of issues impacting a variety of industries, visit http://www.stat.tamu.edu/~vjohnson/.Adjusting GPAs: A Statisticians Effort to Tackle Grade Inflation

Adjusting GPAs: A Statisticians Effort to Tackle Grade Inflation

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11 Responses to Adjusting GPAs: A Statistician’s Effort to Tackle Grade Inflation

  1. Cody Blankenship February 12, 2014 at 8:46 pm #

    As a student I do not see a problem in the grading scale, but maybe a problem with the teacher. The instructor of the course has total control of the exams and grades. I believe if the teachers could potentially give out more challenging exams it could eliminate the problem, but the teacher also has to be expected to cover more difficult material. Of course, you do have some that are extremely gifted in apprehending knowledge, and they will continue to achieve high grades. However, you will be able to see a better reflection on where the student norm is compared to with an easier exam. My reflection on this topic also comes with a bias due to my knowledge only pertains to my current university(WVU). I believe that at the Ivy League level of learning you have more gifted learners that could see success with adjusting the GPA, but not as much for Universities that are not as exclusive in acceptance.

  2. Cody Blankenship February 12, 2014 at 8:42 pm #

    As a student I do not see a problem in the grading scale, but maybe a problem with the teacher. The instructor of the course has total control of the exams and grades. I believe if the teachers could potentially give out more challenging exams. Of course, you do have some that are extremely gifted in apprehending knowledge, and they will continue to achieve high grades. However, you will be able to see a better reflection on where the student norm is compared to with an easier exam. My reflection on this topic also comes with a bias due to my knowledge only pertains to my current university(WVU). I believe that at the Ivy League level of learning you have more gifted learners that could see success with adjusting the GPA, but not as much for Universities that are not as exclusive in acceptance.

  3. BWMorlan February 11, 2014 at 9:15 pm #

    As a statistician I have to ask why we give grades at all? If the purpose is to measure performance against a standard, as in I wanted you to learn your ABCs and you did, therefore you get an A, that leads to one answer, and the comment that a C reflects bad teaching is correct. But when I am sitting on a selection committee looking for whom to admit to graduate school I also want to know if you are a better student than other applicants, in which case I would prefer to see some C’s even if I would not admit them. Of course, it is easy to give A’s in courses that don’t have good standards, just as it is easier for judges to give all gymnasts 10’s, but harder to give all baseball teams wins. Boils down to the difference between art and sports, and A vs C boils down to who do I want serving me coffee and who do I want designing bridges.

  4. Student View February 11, 2014 at 5:18 pm #

    As a student I believe that there is no problem with grade inflation. To say that institutions and or professors are inflating grades is preposterous. Seeing that the stat given of more “A’s” being achieved now than in the past leads me to believe that society as a whole has advanced intellectually, which would be for the best, and education is now being taken more seriously. Also, better strategies for studying are being promoted. In most colleges a “First-Year Seminar” is being required by all incoming freshman to take and pass. It is a course that basically teaches students better ways to study. This would lead to higher test grades as opposed to leaving students out to dry and to learn on their own.
    On the other hand as I see in my classes the average grade is usually much lower than an “A” and to say that it is easy to get an “A” is insulting to someone who has a 4.0 GPA.

  5. Statistical Observer February 11, 2014 at 9:42 am #

    When I taught, I assigned grades by setting point targets. 80-100 – A 70-80 B etc.

    Thus, if every person in the class got an 80 or higher, they all got As. This is not grade inflation. This is the students performing appropriately in the class. In point of fact, if you are good teacher, everyone should get an A. A C is a teaching failure.

    There is no such thing as grade inflation. There are changes in standards.

  6. Christopher Jastram February 10, 2014 at 5:20 pm #

    Most professors at my school graded by points, often amounting to many hundreds of points by the end of the semester. For example, there might be 3 exams worth 100 points each, a final worth 200 points, and homework worth an additional 200 points, for a total of 700 points. Those points are then normalized against a 0-100 scale, and grade letters assigned.

    Why not have the normalization against GPA be performed against the base scale, by the university instead of the professor? This frees the professor from the grade/feedback trap, and leads to a GPA that more accurately reflects actual performance (average, below average, above average).

    Of course, this proposal does not address a problem of decreasing average student performance. However, this problem is certainly not being handled in the current system, and would not seem to be worsened under this proposal.

  7. dt February 10, 2014 at 4:55 pm #

    No doubt that higher grades and positive course evaluations are related, but wouldn’t that make sense? A course that is taught well, should result in higher marks and better instructor evaluations.

    Perhaps what the author is suggesting is that teaching has improved and students actually know more today than they did thirty or forty years ago.

    In which case higher grades are a sign the system is working.

  8. allen February 10, 2014 at 4:07 pm #

    Many of the courses have common examinations. While partial credit may be given more easily the TA is usually responsible for that not the professor. Often some professors are just better than others. The physics teacher I had that used photocopies of the book for overhead slides and had a rudimentary grasp of the English language was a poor teacher. My calculus teacher that offered open study review before examinations and used clear an concise explanations was great.
    The first was a better researcher, but that does not translate into instruction. The better direction would be for universities to focus more on the product of education and less on research grants.

  9. M. Townes February 10, 2014 at 1:32 pm #

    Agreed grade inflation is a problem, but the assumption that grading practices and teaching ability are separable is false. Also, the assumption that teaching and learning methods have not improved in 40 years, never mind the Flynn effect, is pretty ambitious.

    College students pay money to learn things, and are graded on whether or not they learn those things. In most cases, a student will learn if the professor does a good job of teaching. Why would a student choose professors who self-report (through grades) that they do a bad job of teaching? An excellent professor can teach everyone in the class all of what they need to know, and give everyone an A with a clear conscience; of course students want those classes. Professor Johnson’s approach would penalize such professors and their students by normalizing their performance against incompetent colleagues.

    The source of grade inflation — the disconnect between grades and mastery of curriculum — has a pretty clear culprit: the grading curve. Lazy professors will curve their way out of failing an entire class, rather than put any effort into learning how to teach. If Professor Johnson wants to make a dent in grade inflation, he should be working to ban the grading curve.

  10. Never_Underestimate February 10, 2014 at 12:47 pm #

    @Harland – either you did not actually read this article or you just did not understand what you read. There is nothing in this research to indicate anything of the sort that you suggest. As someone with a life-long career in both secondary and higher education, I can attest that grade inflation exists, regardless of racial or ethnic backgrounds. I left a teaching position because it was so blatant. If you were to do a little research about the subject rather than just tossing out non-sequiturs, you would see that there is a large body of research on the subject.

  11. Harland February 10, 2014 at 12:24 pm #

    I notice that this article totally fails to address the elephant in the room: the racism issue. How do we know that this wasn’t an attempt by a white male to lower the GPAs of colored competitors? Statistics had a long and sordid history of being misused in this way.

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