Brown Professor Switches Final Exam to In-Class Test After AI Cheating Halves Student Scores

At Brown University, a prestigious Ivy League institution in Providence, Rhode Island, a professor's decision to move a final economics exam from a take-home format to an in-class test revealed widespread AI misuse among students. Professor Robert Serrano, who teaches "Welfare Economics and Social Choice," observed that the average score on the take-home midterm exam was an unusually high 96, with 40 out of 86 students scoring a perfect 100. This starkly contrasted with previous semesters' averages of 65 to 80, raising suspicions of cheating using AI chatbots like ChatGPT.

Serrano and his teaching assistants tested the exam questions on ChatGPT and found the AI's answers closely resembled those submitted by students, albeit with a convoluted style. Concerned about academic integrity, Serrano reverted the final exam to a traditional in-class format. Following this change, 18 students dropped the course and nine did not attend the final exam. The results confirmed his concerns: the average final exam score plummeted to 48.6, with three students receiving zero and many failing.

In response, Serrano invalidated the take-home midterm scores and weighted the final exam as 80% of the course grade. He also lowered the passing threshold to 40 from 50. Despite these adjustments, 19 students ultimately failed the course. Serrano emphasized the societal risks of tolerating cheating, stating, "We cannot afford a society where a significant portion of the brightest young minds think cheating is acceptable," warning it would lead to societal decline.

This incident highlights the challenges elite universities face in maintaining academic standards amid the rise of AI tools that can facilitate cheating, even in highly selective environments like Brown, which admits only about 5.5% of applicants. The episode also occurred in the shadow of a tragic shooting at Brown in December 2022, which had influenced the initial decision to allow take-home exams for safety reasons.