An AI-supervised remote exam went so badly that 58,000 students must retake it
Ars Technica Nate Anderson ● Covered by 2 sources
Mexico's biggest university let nearly 160,000 people take its entrance exam remotely with AI webcam proctoring. Scores spiked so suspiciously that 58,000 people now have to retake it in person.
Based on reporting by Ars Technica, Nate Anderson — read the original for the full story.
Summary, retelling and take written by AI under human oversight; images are AI-generated illustrations. How we work · Report an error
UNAM, Mexico's largest university, decided this year to let applicants sit its entrance exam from home for the first time, leaning on a lockdown browser and AI-powered webcam monitoring instead of a room full of proctors. Nearly 160,000 people took the test over several weeks between late May and early June. Then the results came back, and something was clearly off.
On the 120-question exam, roughly 3.5 percent of applicants scored 100 or above in a typical year between 2021 and 2025. This year that number jumped to 16.3 percent. At the very top of the scale it was even starker: scores of 110 or higher went from about 0.9 percent historically to 5.5 percent this year. Numbers like that don't drift on their own, and accusations of cheating followed almost immediately.
UNAM's response was to convene a commission of experts, saddled with a name so long it barely fits on one line, to figure out what happened and what to do about it. Their answer, just submitted, is a do-over. A new "control exam" will be given in person, and it won't just apply to this year's crop of applicants. Anyone who would have cleared the minimum admission scores for their program going back to 2021 is now caught up in it too, which puts roughly 58,000 people back in the testing room.
The timing is brutal. Classes are supposed to start August 10, so UNAM either has to pull off a fast, high-stakes retest or push back the semester, and details on how the control exam will actually work still haven't been published. According to the university's own Gaceta UNAM, the rector has apologized to the students who did nothing wrong and now have to prepare all over again, while insisting the redo is necessary to protect fairness in who gets in.
My take — AI-written commentary, not fact-checked reporting
Handing exam integrity over to webcam software and a lockdown browser and hoping it holds for 160,000 people at once was always a gamble, and this is what losing that gamble looks like. The people paying for it aren't the ones who gamed the system, they're the honest applicants now stuck retaking a test with weeks to spare before classes start. Institutions keep treating AI proctoring as a plug-and-play fix for scale, and stories like this are the receipt showing it isn't.
Read more about this at: Ars Technica
