Princeton, N.J. ? For students at Princeton University, final exams are even more stressful this year: The Ivy League school decided to make it harder to earn an A.

The crackdown on high grades, part of a national battle against grade inflation at elite schools, has increased anxiety, and in some cases, made friendly students wonder whether they should offer study help to their competitors, er, classmates.

“Sometimes, your old high school mentality comes back to haunt you,” said Monica Saumoy, recalling the cutthroat competition to get the grades she needed to get into Princeton.

As she studied for an organic chemistry exam last week in a coffee shop, the sophomore and aspiring doctor said she was doing her best to remain cooperative with her peers as they all aim for high grades.

“You don’t want to stop helping people,” she said.

But they all know those A’s aren’t going to be as plentiful.

In a move students protested last year, Princeton became the first elite college to cap the number of A’s that can be awarded.

Previously, there was no official limit to the number of A’s handed out, and nearly half the grades in an average Princeton class have been A-pluses, A’s or A-minuses. Now, each department can give A’s to no more than 35 percent of its students each semester.

Princeton’s effort is being monitored closely by other hallowed halls, and some expect to see a ripple effect in coming years.

Monica Saumoy, a Princeton University sophomore from Short Hills, N.J., says she is doing her best to stay competitive with other students. The university's new policy on grade-inflation limits grades of A-plus, A or A-minus to no more than 35 percent in each department.

At other Ivy League schools, the percentages of A’s in undergraduates courses ranges from 44 percent to 55 percent, according to Princeton’s Web site. At Harvard University, 91 percent of seniors graduated with some kind of honors in 2001.

If the reaction of Princeton students is any indication, limiting honors may mean sharper elbows. Princeton students — never exactly slackers — have been studying even harder this semester, said Tom Brown, executive secretary of the student government.

“You do feel you might be one of the ones they just cut off,” said Natasha Gopaul, a senior at Princeton’s Woodrow Wilson School of Public and International Affairs.

Grade inflation seems to date to the Vietnam War era, when many professors were reluctant to flunk students and consign them to the draft. Other factors made it snowball, including tuition increases that have convinced some students and parents that good grades are an entitlement.

The problem tends to feed on itself; if one department or school is doing it, others are under pressure to follow, or risk putting their students at a disadvantage.

Several schools have made efforts to rein in ballooning grade-point averages. Starting this year, Harvard will limit the number of students who can graduate with honors. Northwestern University set up a committee to study grade inflation at its journalism school.

In 1997, Duke flirted with adopting a complex class-ranking system formula that would have made an A in a class taught by a professor who gives a lot of A’s worth less than one in a class taught by a stingier faculty member.

Valen E. Johnson, the Duke professor who designed that system and went on to write the 2003 book, “Grade Inflation: A Crisis in College Education,” doesn’t like Princeton’s new system.

“There’s a danger that they’re going to drive students away from classes perceived as being competitive,” said Johnson, now a professor at the University of Texas’ MD Anderson Cancer Center in Houston.

Students are particularly worried about having fewer A’s given out in upper-level classes.

“Especially if there are only five people in a class,” said Jon Epstein, a junior computer science major from Cleveland. “It will create more competition to get A’s.”

Princeton officials will send letters to about 3,000 graduate schools and employers to explain the new grading standards — helping assuage students’ fears about losing out to students at other elite schools.

Saumoy, the pre-med student, remains nervous.

“I’ve heard that med schools don’t really care what school you came from,” she said.