Cheating with AI? Ivy League students’ scores drop dramatically during in-person exam
“We cannot choose to become idiots.”
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- Brown professor Roberto Serrano suspected students used AI to cheat after take-home midterm scores averaged 96%, far above past results.
- He moved the final exam in person; 18 students dropped the class and nine others skipped the test.
- The final exam average fell to 48.6%, with only a few students matching their midterm performance.
- The case highlights growing concerns that generative AI is making academic cheating harder to detect and prevent.
A Brown University economics professor suspects most of his class cheated using AI throughout the semester after an in-person exam revealed a significant drop in scores.
After a mass shooting in December 2025 at Brown University, killing two students and injuring nine, many didn’t feel safe coming to the classroom, Inside Higher Ed reports.
As a result, Professor Roberto Serrano allowed students to take their midterm exam in advanced undergraduate welfare economics at home.
The class typically attracted up to 30 students, but this spring, 86 undergraduates chose the course, which, according to Serrano, can be attributed to the possibility of take-home exams.
Another surprise was the midterm exam’s high average score of 96%, way above historical averages ranging between 65% and 80%.
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A nearly perfect score raised suspicions, so Serrano and his graders ran the test through ChatGPT, the most used chatbot in the world. They found many similarities between students' answers and those produced by AI.
For instance, when asked to prove a mathematical statement, ChatGPT and many students used a “contradiction argument,” even though a “direct argument” was the most obvious option.
Serrano told Inside Higher Ed that it was obvious the answer wasn’t written by a human.
With the dean's blessing, Serrano changed the final exam to an in-person test. He told the students that if the final exam score is roughly the same as the midterm score, he will count the midterm result.
“Otherwise, which is of course what I expect to happen, I will declare the midterm void and reweigh the final accordingly,” he is quoted as saying.
Eighteen students dropped the classes immediately. Another 9 remained enrolled, but did not take the exam. Three students earned a zero on the final exam, bringing the average score to 48.6%, a new historical low.
Only a handful of students earned final exam scores that matched their midterm scores.
Using AI to cheat is increasingly common
The explosive growth of generative AI in late 2022 raised concerns about its impact on learning and academic honesty.
A 2025 survey of Princeton University seniors found that 27.7% admitted to using ChatGPT when it was not allowed, up 12.5% from the Class of 2024.
Serrano said that a society in which a significant faction of young minds believes cheating is acceptable leads to decline and failure.
He added, “We cannot choose to become idiots.”