How Republican and Democratic Professors Grade

Talia Bar and Asaf Zussman article explore \”Partisan Grading\” in the most recent issue (vol. 4, number 1) of the American Economic Journal: Applied Economics. The  article is not freely available on-line, although many can get on-line access to it if your library has a subscription to the publications of the American Economic Association. As they explain in their abstract: \”We study grading outcomes associated with professors in an elite university in the United States who were identified—using voter registration records from the county where the university is located—as either Republicans or Democrats. The evidence suggests that student grades are linked to the political orientation of professors.\”

Their useful starting point is that they have data on SAT scores for students–which are on average a good predictor of college grades. Measured by this standard, they show that the distribution of students headed into the classrooms of Republican and Democrat professors is essentially the same. However, the grading outcomes are not the same.

They have data from \”the College of Arts and Sciences of an elite university in the United States between the spring semester of 2000 and the spring semester of 2004.\” More specifically, they have grades of 17,062 students taking 3,277 undergraduate level courses with 417 professors. They find:

\”[T]he variance of grades is higher in courses taught by Republicans than in courses taught by Democrats. Moreover, in additional analysis, we find that relative to their Democratic colleagues, Republican professors tend to assign more very low and very high grades. The share of the lowest grades (F, D−, D, D+, and C−) out of the total is 6.2 percent in courses taught by Republican professors and only 4.0 percent in courses taught by Democratic professors. The share of the highest grade (A+) out of the total is 8.0 percent in courses taught by Republican professors and only 3.5 percent in courses taught by Democratic professors. Both differences are highly statistically significant.\”

This general  pattern holds up after adjusting for differences in grading across academic departments. Here\’s a graphical illustration of the same general theme. The horizontal axis shows SAT scored of students; the vertical axis shows the average grade received by students. Notice that students with low SAT scores–say, under 1200–receive an average grade of about 2.4 in classes taught by Republican professors, but 2.9 in classes taught by Democrat professors. At the higher end of the range, students with about 1400 on their SATs up to about 1600 get roughly the same grades on average from Democrat professors, at about 3.4. However, students with SAT scores in the top 1560-1600 range on average get grades of about 3.6 from Republican professors.

The authors are at pains to emphasize that there are multiple possible interpretations of these findings.

\”One interpretation is that it reflects a difference in grading practices but not in student performance. In other words, an identical distribution of student performance will translate into different distributions of grades, with Republican professors tending more than their Democratic colleagues to assign low grades to low-ability students and high grades  to high-ability students.

\”An alternative way to interpret the finding is that it reflects a difference in student performance but not in grading practices. The difference in student performance could be related to the amount of effort professors are willing to invest in helping students of different abilities or in the extent to which professors encourage students of different abilities. For example, it is possible that Democratic professors would devote more resources (e.g., in office hours time) to helping low-ability students, while Republican professors would devote more resources to nurturing high-ability students. It may also be the case that Republicans have different teaching or testing styles than Democrats (for example, with different needs for memorization or creativity), and that student performance varies across these heterogeneous learning environments. An additional possibility is that Democrats differentially reward something other than pre-existing talent.

\”These interpretations are all consistent with our hypothesis. … The important point from our perspective is that the evidence suggests that Republican professors are associated with less egalitarian grading outcomes.\”

 While Barr and Zussman are professionally cautious in their interpretation, readers are of course free  to offer their own interpretations. Let the parade of anecdote, speculation, innuendo and overstatement commence!

Grade Inflation and Choice of Major

Like so many other bad habits, grade inflation is lots of fun until someone gets hurt. Students are happy with higher grades. Faculty are happy not quarreling with students about grades.

When I refer to someone getting hurt by grade inflation, I\’m not talking about the sanctity of the academic grading process, which is a mildly farcical concept to begin with and at any rate too abstract for me. I\’m also not referring to how it gets harder for law and business schools to sort out applicants when so many students have high grades. In the great list of social problems, the difficulties of law and B-school admissions offices don\’t rank very high.

To me, the real and practical problem of grade inflation is that it causes students to alter their choices, away from fields with tougher grading, like the sciences and economics, and toward fields with easier grading.
A couple of recent high-profile newspaper stories have highlighted that college and university courses in the \”STEM\” areas of science, technology, engineering and mathematics tend to have lower average grades than courses in humanities, which is one factor that discourages students from pursuing those fields. Here\’s an overview of those stories, and then some connections to more academic treatments of the topic from my own Journal of Economic Perspectives.

A New York Times story on November 4, by Christopher Drew, was titled, \”Why Science Majors Change Their Minds (It’s Just So Darn Hard).\”  Drew writes: \”Studies have found that roughly 40 percent of students planning engineering and science majors end up switching to other subjects or failing to get any degree. That increases to as much as 60 percent when pre-medical students, who typically have the strongest SAT scores and high school science preparation, are included, according to new data from the University of California at Los Angeles. That is twice the combined attrition rate of all other majors.\”

Part of the reason is that most of the STEM fields start off with a couple of years of tough, dry, abstract courses, for which many students are not academically or emotionally prepared. Another reason is that the grading in these courses is tougher than in non-STEM fields. Drew describes some of the evidence: \”After studying nearly a decade of transcripts at one college, Kevin Rask, then a professor at Wake Forest University, concluded last year that the grades in the introductory math and science classes were among the lowest on campus. The chemistry department gave the lowest grades over all, averaging 2.78 out of 4, followed by mathematics at 2.90. Education, language and English courses had the highest averages, ranging from 3.33 to 3.36. Ben Ost, a doctoral student at Cornell, found in a similar study that STEM students are both “pulled away” by high grades in their courses in other fields and “pushed out” by lower grades in their majors.\”

(For those who want the underlying research, the Rask paper is available here, and the Ost paper is available 

On November 9, the Wall Street Journal had a story called \”Generation Jobless: Students Pick Easier Majors Despite Less Pay,\” written by Joe Light and Rachel Emma Silverman.

\”Although the number of college graduates increased about 29% between 2001 and 2009, the number graduating with engineering degrees only increased 19%, according to the most recent statistics from the U.S. Dept. of Education. The number with computer and information-sciences degrees decreased 14%.\” Again, part of the problem is insufficient preparation before college for the STEM classes, and part is the discouragement of getting lower grades than those in non-STEM fields. Also, even with lower grades, the STEM majors are more work: \”In a recent study, sociologists Richard Arum of New York University and Josipa Roksa of the University of Virginia found that the average U.S. student in their sample spent only about 12 to 13 hours a week studying, about half the time spent by students in 1960. They found that math and science—though not engineering—students study on average about three hours more per week than their non-science-major counterparts.\”

(For those who want to go for original sources, Arum and Roksa discuss the several thousand students that they surveyed over several years in their 2011 book Academically Adrift: Limited Learning on College Campuses. When they make comparisons back to how much students studied in 1960s, they are drawing on work by Philip Babcock and Mindy Marks. For a readable overview of that work, see their August 2010 essay on \”Leisure College, USA: The Decline in Student Study Time,\”  written as an Education Policy brief for the American Enterprise Institute. For the technical academic version of their work, see their essay in the May 2011 Review of Economics and Statistics (Vol. 93, No. 2, Pages 468-478), \”The Falling Time Cost of College: Evidence from Half a Century of Time Use Data.\”

As noted, there are lots of reasons why students don\’t persevere in STEM courses: inadequate preparation at the high school level, students who have unrealistic expectations or don\’t want to commit the time to studying, or that the courses are just hard. It\’s of course possible to address these issues, but difficult. However, if one of the issues discouraging students from taking STEM courses is that grade inflation is happening faster in the humanities, then surely, this cause at least is fixable? In my own Journal of Economic Perspectives, which is freely available from the current issue going back to the late 1990s courtesy of the American Economic Association, several authors have taken a stab at quantifying the differences in grades across majors and what difference it makes to course choice.

The first such paper we published was back in the Winter 1991 issue. It was by Richard Sabot and John Wakemann-Linn, and called \”Grade Inflation and Course Choice.\” It\’s too far back to be freely available on-line, but it\’s available through JSTOR. The complaints in that article sound quite familiar. They write:

\”The number of students graduating from American colleges and universities who had majored in the sciences declined from 1970-71 to1984-85, both as a proportion of the steadily growing total and in
absolute terms. … Students make their course choices in response to a powerful set of incentives: grades. These incentives have been systematically distorted by the grade inflation of the past 25 years. As a consequence of inflation, many universities have split into high- and low-grading departments. Economics, along with Chemistry and Math, tends to be low-grading. Art, English, Philosophy, Psychology, and Political Science tend to be high-grading.\” They present more evidence on grade inflation and course choice from Amherst College, Duke University, Hamilton College, Haverford College, Pomona College, the University
of Michigan, the University of North Carolina and the University of Wisconsin, and more detailed analysis from their own Williams College. As they write: \”This sample is admittedly small, but was selected so as to include private and state schools, large universities and small colleges, and Eastern, Southern, Midwestern and Western schools.\”

Based on more detailed statistical analysis from Williams College, where they have access to more detailed data, they write: \”Our simulation indicated that if Economics 101 grades were distributed as they are in English 101, the number of students taking one or more courses beyond the introductory course in Economics would increase by 11.9 percent. Conversely, if grades in English 101 were distributed as they are in Economics 101, the simulation indicated that the number of students taking one or more courses beyond the introductory course in English would decline by 14.4 percent. The results of applying this method to-the Math department, which had the lowest mean grade and the highest dispersion of grades, are more striking. If the Math department adopted in its introductory course the English 101 grading distribution, our simulation indicated an 80.2 percent increase in the number of students taking at least one additional Math course! Alternatively, if the English department adopted the Math grade distribution, there would be a decline of 47 percent in the number of students taking one or more courses beyond the introductory course in English.\”

We took another swing at the issue of grades and course choice with a couple of articles in our Summer 2009 issue. Alexandra C. Achen and Paul N. Courant asked \”What Are Grades Made Of?\” They argue: \”Grades are an element of an intra-university economy that determines, among other things, enrollments and the sizes of departments. … Departments generally would prefer small classes populated by excellent and highly motivated students. The dean, meanwhile, would like to see departments supply some target quantity of credit hours—the more the better, other things equal—and will penalize departments that don’t do enough teaching. In this framework, grades are one mechanism that departments can use to influence the number of students who will take a given class.\”

Focusing on 25 years of grade data from the University of Michigan, they find:  \”First, the distribution of grades is likely to be lower where courses are required, and where there are agreed-upon and readily assessed criteria—right or wrong answers—for grading. By contrast, departments that evaluate student performance using interpretative methods will tend to have higher grades, because using these methods increases the personal cost to instructors of assigning and defending low grades. Second, upper-division classes are likely to have higher grades than lower-division classes, both because students have selected into the upper-division courses where their performance is likely to be stronger and because faculty want to support (and may even like) their student majors. Third, grades can be used in conjunction with other tools to attract students to departments that have low enrollments and to deter students from courses of study that are congested. We find some evidence in support of each of these patterns. As it happens, the consequence of the preceding tendencies is that, indeed, the sciences (mostly) grade harder than the humanities. …\”
\”We argue that differential grading standards have potentially serious negative consequences for the ideal of liberal education. At the same time, we conclude that any discussion of a policy response to grade inflation must begin by recognizing that American colleges and universities are now in at least the fifth decade of well-documented grade inflation and differences in grading norms by field. Current grading behavior must and will be interpreted in the context of current norms and expectations about grades, not according to some dimly imagined (anyone who actually remembers it is retired) age of uniform standards across departments. Proposals that attempt to alter grading behavior will face the costs of acting against prevailing customs and expectations, whether in altering pre-existing patterns of grades across departments within a college or university or in attempting to alter grades in one institution while recognizing that other universities may
not change.\”
In that same issue, Talia Bar, Vrinda Kadiyali, and Asaf Zussman discuss one proposal to alter the incentives for grade inflation about \”Grade Information and Grade Inflation: The Cornell Experiment.\” They report that in \”April 1996, the [Cornell] Faculty Senate voted to adopt a new grade reporting policy which had two parts: 1) the publication of course median grades on the Internet; and 2) the reporting of course median grades in students’ transcripts. … Curbing grade inflation was not explicitly stated as a goalof this policy. Instead, the stated rationale was that “students will get a more
 accurate idea of their performance, and they will be assured that users of the transcript will also have this knowledge.\”

To given a sense of the institutional obstacles here, they report that while median grades were publicly available on-line in 1998, at the time the article was written this information did not yet appear on actual student transcripts. As they point out, making this information available may have the undesired effect of encouraging students even  more to take courses with easier grades! They also argue that the propensity to take easier-grading courses will be greater for lower-ability students. Thus, student will tend to sort themselves into higher-ability students in tougher-grading classes, and lower-ability students in easier-grading classes. Indeed, they estimate that nearly half of the grade inflation for Cornell as a whole, in the years after median grades were posted on the web, was attributable to students sorting themselves out in this way.

In short, grade inflation in the humanities has been contributing to college students moving away from science, technology, engineering, and math fields, as well as economics, for the last half century. It\’s time for the pendulum to start swinging back. A gentle starting point would be to making the distribution of grades by institution and by academic department (or for small departments, perhaps grouping a few departments together) publicly available, and perhaps even to add this information to student transcripts. If that answer isn\’t institutionally acceptable, I\’m open to alternatives.