AI proctoring flunked the exam: 58,000 applicants will retake it

This summer nearly 160,000 people sat the entrance exam at UNAM, Mexico's largest university. For the first time, the test was held entirely remotely: applicants worked in a “locked-down” browser under the watch of an AI proctoring system that monitored them through their webcams. The exam stretched over several weeks — from late May to early June. And it turned into a disaster.

Anomalous results

When the results were tallied, they bore little resemblance to the statistics of previous years — especially at the top of the scale. In 2021–2025, a score of 100 or higher out of 120 questions was earned by 3.5% of test-takers. This year it was 16.3%. The contrast is even starker at the very top: a result of 110 or higher was previously achieved by 0.9% of participants, and now by 5.5%.

The sharp spike in high scores triggered accusations of mass cheating. UNAM convened a panel of experts with an imposing name, which has just presented its recommendations: to hold a “verification exam” — that is, to make applicants take the test again, this time in person.

Who will be affected

The retake will affect not only those who qualified on this year's scores, but everyone who would have been admitted under the minimum passing scores for their programs going back to 2021. Around 58,000 people are caught in the net, and their places now depend on the new test. The rector apologized to the honest applicants who will have to study all over again through no fault of their own, but called the verification exam “necessary to guarantee fairness of access.” Classes, meanwhile, are supposed to begin on August 10, so they'll have to move fast.

How the safeguards were bypassed

The exam was multiple-choice rather than essay-based, so the usual traces of AI cheating (instantly pasting in ready-made answers) are hard to find. As the New York Times noted, tips for cheating were circulating even before the start: applicants were advised to set up a second monitor just outside the webcam's frame and keep ChatGPT open on it, hide earbuds under their hair, or even hire someone to take the exam out of view.

The protective measures didn't help. The exam used Respondus's LockDown browser, which blocks printing, copying, navigating to other sites and hundreds of other functions, along with Territorium's AI proctoring system, which watched for person-swapping, phones, earbuds and leaving the frame. There was one live monitor for every 150 test-takers. UNAM voided about 2% of the papers for violations, but that is clearly not enough: the university itself acknowledged the likelihood that a “significant number” of applicants had received help. According to AI expert Raúl Rojas, statistical modeling indicates that nearly half of those who took the exam online were cheating.

Now nearly 58,000 people will take up the questions again — but this time in an official exam hall and under the watch of a live proctor.

Source: Ars Technica