The extent of student cheating, difficult to measure precisely, appears widespread at colleges. In surveys of 14,000 undergraduates over the last four years, an average of 61 percent admitted to cheating on assignments and exams.

The figure declined somewhat from 65 percent earlier in the decade, but the researcher who conducted the surveys, Donald L. McCabe, a business professor at Rutgers, doubts there is less of it. Instead, he suspects students no longer regard certain acts as cheating at all, for instance, cutting and pasting a few sentences at a time from the Internet.

Andrew Daines, who graduated in May from Cornell, where he served on a board in the College of Arts and Sciences that hears cheating cases, said Internet plagiarism was so common that professors told him they had replaced written assignments with tests and in-class writing.

Mr. Daines, a philosophy major, contributed to pages that Cornell added last month to its student Web site to bring attention to academic integrity. They include a link to a voluntary tutorial on avoiding plagiarism and a strongly worded admonition that “other generations may not have had as many temptations to cheat or plagiarize as yours,” and urging students to view this as a character test.

Mr. Daines said he was especially disturbed by an epidemic of students’ copying homework. “The term ‘collaborative work’ has been taken to this unbelievable extreme where it means, because of the ease of e-mailing, one person looking at someone else who’s done the assignment,” he said.

At M.I.T., David E. Pritchard, a physics professor, was able to accurately measure homework copying with software he had developed for another purpose — to allow students to complete sets of physics problems online. Some answered the questions so fast, “at first I thought we had some geniuses here at M.I.T.,” Dr. Pritchard said. Then he realized they were completing problems in less time than it took to read them and were copying the answers — mostly, it turned out, from e-mail from friends who had already done the assignment.

About 20 percent copied one-third or more of their homework, according to a study Dr. Pritchard and colleagues published this year. Students who copy homework find answers at sites like Course Hero, which is a kind of Napster of homework sharing, where students from more than 3,500 institutions upload papers, class notes and past exams.