Harvard University is investigating whether about 125 undergraduates "inappropriately collaborated" or copied answers on a spring semester take-home final exam, the school announced today.

It's being called the largest cheating scandal in recent memory to hit the elite university and the Ivy League.

The students -- about half the class -- violated a no-collaboration policy printed on the exam, which consisted of short questions and an essay, said Jay Harris, dean of undergraduate education, the Boston Globe reports. The students allegedly collaborated through e-mail or "other means," and some may have copied their answers.

The cheating was uncovered after faculty noticed similarities among a number of exams and referred them for administrative review. All will face hearings, and those found to have plagiarized may have to withdraw for a year.

The administrative board's actions are confidential, Harris said, and the identities of the students or the course will not be revealed.

"These allegations, if proven, represent totally unacceptable behavior that betrays the trust upon which intellectual inquiry at Harvard depends," Harvard University President Drew Faust said in the announcement. "We must deal with this fairly and through a deliberative process. At the same time, the scope of the allegations suggests that there is work to be done to ensure that every student at Harvard understands and embraces the values that are fundamental to its community of scholars."

The announcement states:

While the allegations are limited to one class, FAS administrators and faculty members are taking a number of steps to underscore the importance of academic integrity for students even as the Administrative Board's review continues. First among those steps: The College Committee on Academic Integrity, chaired by Dean of Undergraduate Education Jay Harris, is expected to present a set of recommendations to reinforce the faculty's expectations of academic honesty. The committee, composed of faculty, undergraduate students, resident deans, and administrators, has been consulting with faculty and students in the College and assessing the practices of peer institutions on a range of actions, from the adoption of new ethics policies to the possible introduction of an honor code. Additionally, a member of the Administrative Board staff has been tasked with building awareness among faculty and students about Harvard's academic integrity policies. The College also will engage with outside experts on academic integrity as they initiate a campuswide discussion about this issue. College officials will work with Housemasters and resident deans to convene a series of House-level conversations about academic integrity issues, taking advantage of Harvard's unique residential life system to promote House-level dialogue on a community-wide scale.

The Globe addresses the possibility of earlier cheating and remedies:

The number of students under investigation suggests that similar cheating may have occurred in other courses or previous iterations of the course in question. But Harvard officials do not plan to investigate that possibility unless other faculty members to come forward with suspicions of their own, and "we don't anticipate that," Harris said. Instead, administrators will consider preventive measures, including the possibility of instituting an academic honor code -- an idea that has recently piqued interest at Harvard despite the college's history of resisting such a move.

Here's some of what the school lays out regarding plagiarism and collaboration under the heading "Academic Dishonesty" in the student handbook:

It is expected that all homework assignments, projects, lab reports, papers, theses, and examinations and any other work submitted for academic credit will be the student's own. Students should always take great care to distinguish their own ideas and knowledge from information derived from sources. The term "sources" includes not only primary and secondary material published in print or online, but also information and opinions gained directly from other people. Quotations must be placed properly within quotation marks and must be cited fully. In addition, all paraphrased material must be acknowledged completely. Whenever ideas or facts are derived from a student's reading and research or from a student's own writings, the sources must be indicated. Students must also comply with the policy on collaboration established for each course, as set forth in the course syllabus or on the course website. Policies vary among the many fields and disciplines in the College, and may even vary for particular assignments within a course. Unless otherwise stated on the syllabus or website, when collaboration is permitted within a course students must acknowledge any collaboration and its extent in all submitted work; however, students need not acknowledge discussion with others of general approaches to the assignment or assistance with proofreading. If the syllabus or website does not include a policy on collaboration, students may assume that collaboration in the completion of assignments is permitted. Collaboration in the completion of examinations is always prohibited. ...

In 2010, Harvard senior Adam Wheeler was found to have used forged recommendations to get into the school, then used plagiarized essays to apply for scholarships, Bloomberg notes.