Students who took Government 1310: “Introduction to Congress” in recent years describe a course with a noted culture of collaboration, a practice that eventually led to alleged widespread cheating after the professor added a difficult short answer component to the course’s take-home exams.

Some students have expressed frustration or dismay at the unexpected difficulty and changed expectations in the spring 2012 version of the course.

The lecture class entered the national spotlight following Harvard’s announcement on Thursday that it is currently investigating about 125 students for plagiarizing responses or inappropriately collaborating on a final take-home exam in a spring course. Though the administration did not disclose the name of the class, The Crimson reported that it was Matthew B. Platt’s government class.

Platt, who came to Harvard in 2008, has taught the course for the past three spring semesters. He, as well as former teaching fellows, declined or did not respond to requests for comments on the case.

The course’s overall score on the Q Guide has declined over the past three years, falling slightly from 3.70 in spring 2010 to 3.57 in spring 2011. The score dipped more sharply in spring 2012 to a 2.54, following the introduction of the new exam format.

All three years, grades for the course have been calculated based on four equally-weighted take home exams, each worth 25 percent of the final grade.

In spring 2010 and spring 2011, students received the same instructions on each exam, according to the syllabi: write a three-to-five page paper responding to your choice of one of three prompts.

Several students being investigated for cheating in the course in spring 2012 said they had friends in the course in previous years who collaborated on exams using the same practices that landed the students themselves under investigation by the Administrative Board.

Students also said the essay-only exam format contributed to Government 1310’s increasing reputation as an easy course. Fifty-seven percent of students in spring 2010 and 67 percent of students in spring 2011 who evaluated the course’s difficulty on the Q Guide rated the class as “easy” or “very easy.”

But in spring 2012, Platt changed the format of his exams, replacing the essay question with a short answer section containing several multi-part questions, many of which had a definitively right or wrong answer.

The fourth and final take-home exam, which sparked the plagiarism scandal, featured both a short answer section and an essay question.

Students say the new exam format may have also made cheating easier and more obvious to spot. One sophomore who took Government 1310 last spring said that it would be “quite easy to copy” answers in the short answer section of the exam.

Q Guide data suggests that these changes made the course more difficult. In spring 2012, only 16 percent of students who rated the course’s difficulty on the Q Guide called it “easy” or “very easy,” and 37 percent of evaluators rated the course as “difficult” or “very difficult.”

Two students in the class who are not being investigated said they found many of the final exam questions were confusing, leading both of them to email their teaching fellows for clarification.

Eventually, in two emails sent to the class on April 30, Platt was compelled to clarify three short-answer questions on the final exam in response to “some good questions” that he had received about it.

Two students who took the class in 2012 said that they observed other students collaborating on the final exam, which the exam instructions explicitly prohibited. One of those students, another sophomore who took the class in 2012, said that he was approached by students outside Lamont Library who invited him to join them in collaborating.

“It was very obvious that it was going on,” he said. “It was one of those things that wasn’t necessarily trying to be covered up.”

The student added that he felt frustrated with the unprecedented difficulty of the class in 2012, as he had heard it described as an easy class and had already committed to taking five courses that semester.

—Staff writer Gina K. Hackett can be reached at ghackett@college.harvard.edu.

—Staff writer Rebecca D. Robbins can be reached at rrobbins@college.harvard.edu.