With reading week around the corner, Yale’s libraries are brimming with students — some painstakingly sifting through tomes of constitutional law, others attempting to construct the diastereomer (1S, 2R)-1-bromo-1,2-dideuteriopentane with molecular model kits. While history, English and philosophy students begin writing theses for term papers, natural science, mathematics and economics students pull out books and problem sets to prepare for final exams. But regardless of the hours they spend hitting the books, students’ final grades may be substantially influenced by the differing grading methods of their professors.

Some students assume that science and quantitative reasoning classes are uniformly graded on a curve, while humanities grades are based solely on the discretion of the professor. But many science, math and economics professors said the distribution of grades is not as rigid as Yalies think, and students and professors alike cited the wide range of University grading methods as a possible source of grade inflation, an issue that some said deserves more attention at Yale.

Quantitative or qualitative?

Many professors who teach quantitative reasoning and science-related subjects said their grades are determined by formulas. But even though final grades are often assigned based on a curve, that curve often changes from year to year. Economics professor George Hall, who teaches “Introductory Economics,” said there is no general curve for the Economics Department as a whole, and individual professors are typically expected to apply a basic knowledge of historical grade distribution in designing their tests.

“Usually, you try to write an exam that’s going to generate a spread,” he said. “You don’t want everyone to be piled up on one end, … so you pick some easy questions and some hard questions.”

Mathematics professor Steven Orszag said raw math scores in “Calculus of Functions of Several Variables” are based on a weighted average of the two midterms, problem sets and the final. He said the final letter grades are assigned according to major breaks in the grade distribution, not fractions of points, and that the curve is not based on predetermined percentages.

“Math is a quantitative subject, so it’s easy to be fairly quantitative with the grading,” Orszag said.

James Simmons ’09, who is currently taking “Comprehensive Organic Chemistry” and plans to major in biology, said the nature of natural science study makes it easy to grade quantitatively.

“In science, if you’re off by .01, it’s easy for a professor to look at it and show you where you’re wrong,” he said.

But some science professors, including chemistry professor J. Michael McBride, who currently teaches the notoriously difficult “Freshman Organic Chemistry,” said they do not seek to maintain a normal or bell-shaped distribution of grades. Most of the students in his class receive an A or a B at the end of the semester because they elect to study such advanced-level material so early, he said.

“For the most part, it’s not a typical set of students, because they’re ones that have taken a lot of chemistry and physics in high school and worked hard at it,” McBride said. “It doesn’t seem reasonable that they should get bad grades in their chemistry classes.”

Still, McBride said, not every student can ace the class. It is still important to recognize the students who excel beyond their peers, he said.

But for most professors in the humanities, the idea of a curve ­– even a less rigid one — is completely unheard of, and grades are determined according to the standards of the professor or teaching assistant. Keith Wrightson, director of undergraduate studies in history, said it is important to him that grades in his classes are given based on his own judgement.

“I object to any kind of rigidity in education,” he said. “There’s too much of it already.”

Wrightson said he has used a curve in past history classes, but said he felt the decisions he was forced to make at the borderlines between grades were too arbitrary.

“To know in advance that you were going to categorize [grades] is something that fills me with dismay,” he said.

Despite the supposedly straightforward nature of some quantitative classes, many science professors expressed similar opinions.

Physics professor Ramamurti Shankar said there is no single standard formula for grading in his introductory class. He said he does not worry about how many students receive a particular grade because, unlike Hall and other economics professors, he is comparing students to everyone who has taken the class in previous years, as well as their current peers.

“The curve is not based on how many people should get A’s,” he said. “If there are a lot of top students in the class, a lot of them might get A’s, and I am not apologetic about that. If my class contained Heisenberg and Einstein, am I going to give one of them a B?”

Shankar said that, as far as he is concerned, if a student’s final exam grade is better than his or her average, it becomes the student’s final grade.

“I have a notion of what an A student is,” he said. “It’s the finished product I’m more interested in, especially with people who show remarkable mastery at the end.”

Students who drop a class because they know they are at the bottom of the curve also factor into grade distribution. When the weakest students in the class drop out, the average grade increases, and Hall said he does not think students who suddenly find themselves at the bottom of the new curve should be punished. He said his grade distribution would most likely look more severe if all of the weak students did not drop the class after the first midterm.

But despite his adjustments, Hall said he still ends up with a normal distribution at the end of each semester.

Courtesy B or gentleman’s C?

It is a common conception among students that the majority of humanities professors do not give grades below B’s. English professor Fred Strebeigh said a former director of undergraduate studies for the English Department recommended that no more than 50 percent of the grades in a given class be A’s and A-‘s. While Strebeigh said he thinks these guidelines make him a better teacher because he must strive to challenge his students, the grades he assigns are still solely based on his discretion.

“I don’t give many C’s,” he said.

Andrew Beaty ’07, a history major, said he appreciates the lack of curves in humanities classes because he thinks students should receive grades based on the work they do in the eyes of the professor without comparison to their peers. He said he has definitely noticed that the majority of grades tend to fall on the upper end of the scale, but does not think this necessarily suggests grade inflation.

“Professors are pretty liberal in the number of B’s that they give, but in terms of A’s, they’re a bit more stingy,” Beaty said.

Wrightson said he has never given a C, partly because the average Yalie rarely produces work seriously deficient in information, but also due to the advice he received from his colleagues when he first began teaching at Yale.

“There’s no doubt that there’s been some grade inflation over the years,” he said. “I go by the Yale College Program of Study, based on the knowledge that the lower grades are regarded as unusable nowadays.”

Philosophy professor Shelly Kagan said he has a reputation as a particularly hard grader, but he said he does not actually know if that is true, because the University does not publish grade distributions. He simply grades based on an “internal yardstick” he has developed over his years as a professor. Kagan said this yardstick is influenced in part by the guidelines laid out by Yale, but he interprets them slightly differently from Wrightson.

“B means ‘good,'” he said. “That’s a fairly straightforward term. But a lot of Yale students take B to be bad, or at least pretty underwhelming. It’s really that a gap has come in over the decades between the official meanings of the letter grades and the practice of assigning them.”

Kagan said he is confident that students get lower grades in his classes than they do elsewhere at Yale, but he said professors do students a disservice by taking satisfactory work and acting like it is stellar.

“It’s partly out of respect for the students that I try to give genuinely honest evaluations about what the quality of work is,” he said.

Unlike many other professors in the humanities, Kagan said he is not reluctant to give students a C or lower if he thinks that is the grade they deserve.

“It’s clear that grades have crept up over the decades,” he said. “When I was an undergraduate, one could still talk about a ‘gentleman’s C,’ but C’s are no longer acceptable grades. There has been rampant grade inflation over the past 30 or 40 years.”

For professors in the more quantitative departments, charges of grade inflation are not as prevalent, perhaps because C’s are not as rare. Hall said he has not seen instances of inflation in the Economics Department because while D’s are extremely rare, it is still very difficult for students to receive an A.

Wladimir Maracaba ’09, an economics major, said that despite the fact that science students are more likely to get C’s, he is happy that classes are curved because it usually works out better for students.

“What other way would you grade a science class? Usually the tests are really hard, so if you don’t have a curve, everyone’s going to fail,” he said.

Strebeigh said he agreed that it is more important to judge the quality of work accurately than to limit the number of A’s that can be given in a single class. In fact, he said he would even be in favor of adding an A+ option for truly outstanding work.

“It would give students something to reach for, and it would give faculty a truly rare grade that exceptionally excellent work might win,” he said.