The way Lawrence Goldblatt sees it, by the time students reach professional school, they should be trusted to act responsibly on assignments.

"We ought to be able to give them photographs in an envelope and say, 'Don't open these until the exam day.' And they should be able to abide by the rule because it's the right thing to do," said Goldblatt, dean of Indiana University's School of Dentistry.

But earlier this term, nearly half of the second-year students in his program were found to have either taken part in or to have known about and not reported an incident that involved breaking into password-protected files to get an early look at images on an exam.

Cheating, typically thought of as an undergraduate concern, has surfaced recently at several professional schools. Late last month, Duke University's Fuqua School of Business announced that dozens of first-year students violated the honor code by collaborating on a take-home test that was supposed to be completed alone.

Thirty-four students in the M.B.A. program face penalties: 9 expulsion, 15 a one-year suspension and a failing grade in the class, 9 a failing mark in the class and one a failing mark on the assignment.

On Friday, the Faculty Council at Indiana's dental school voted to dismiss 9 of its students, suspend 16 for various lengths of time and send a letter of reprimand to 21 others for violating its professional code of conduct by knowing about and not reporting the incident. The class has just under 100 students.

Two professional conduct committees -- one comprising students and the other faculty -- looked into the cheating allegations and the entire faculty had a say in the final decision.

“This has been a wrenching experience for everyone involved -- for students who made this big error and classmates, faculty, administrators and alumni," Goldblatt said. "It's sad that this happened and it's sad that we had to take this action."

The school has an obligation to take cases of cheating seriously because it certifies that graduates "can be trusted to do the absolute right thing in every situation in their professional lives, even when nobody is looking," he added.

David M. Eberhardt, a research associate at Florida State University's Hardee Center for Leadership and Ethics in Higher Education who writes an ethics column for its Journal of College and Character, said cases of cheating at professional schools aren't surprising given that students might have gotten away with the same practices as undergraduates.

Still, there are structural differences that would seemingly make academic dishonesty less prevalent in graduate programs. They are typically smaller than undergraduate programs, making honor code violations easier to enforce. If you know your instructor and your instructor knows you, wouldn't cheating be unlikely? And since this is commonly the final step before starting a career, why risk blowing years of work for a higher grade?

Then again, as both Eberhardt and Goldblatt point out, professional school faculty tend to be more trusting of their students.

"In my [doctoral] program, professors give take-home exams," Eberhardt said. "It's assumed that you've developed a level of professional integrity that means you aren't going to cheat. But when the pressure is on, some people make choices that aren't ethical."

Don McCabe, a professor of management and global business at Rutgers University who has tracked cheating for 17 years, said that multiple surveys show that graduate students generally admit to cheating less often than undergraduates.

For instance, 56 percent of M.B.A. students reported in one survey cheating in some way from fall 2002 to spring 2004. A comparable survey showed that 74 percent of undergraduate business majors and 68 percent of non-business majors reported cheating.

McCabe asks his students each year to rate the seriousness of different types of cheating. He said the Duke students' infraction, collaborating on a test meant to be taken alone, would be considered serious on the index, but not as egregious as copying another student's exam. The dental school students' actions would likely rate high on the seriousness scale since "outright deception was involved," he said.

And then there's the question of response to cheating. The American Dental Association is sponsoring a symposium on integrity and ethics in dental education next month -- although the topic was chosen prior to the incident at Indiana.

Goldblatt said the dental school has already made changes to its encryption to make code-breaking more difficult. He said that's a minor part of the review process in this case.

"We can create a virtually uncrackable code, but that's still not the answer," he said. "We could look into the background of all 2,100 students who applied for the 100 slots and we still wouldn't find anything [in students' records]. I don't think there's a way in the admissions process we could screen this out. As far as I know, there's no such thing as an integrity test."