58,000 candidates retake university exam amid AI cheating suspicions

High scores increased fivefold in the first online exam, prompting the National Autonomous University of Mexico to organize a re-examination for tens of thousands of candidates.

The National Autonomous University of Mexico (UNAM) has mandated a re-examination for 58,000 candidates following an online entrance exam that saw a nearly fivefold increase in high scores, raising suspicions of widespread artificial intelligence (AI) cheating. This decision, announced after the university's first fully online entrance exam this summer, affects all candidates who met the previous five years' admission threshold. Their official admission now hinges entirely on the results of this new, in-person verification exam.

Nearly 160,000 candidates participated in UNAM's entrance exam, which employed a lockdown browser and AI-integrated webcam monitoring software. The results, however, were unprecedented: over 16,3% of candidates scored 100/120 points or higher, a significant jump from the 2021-2025 period. Furthermore, 5,5% achieved perfect scores, a stark contrast to less than 1% in prior years. This unusual surge prompted UNAM to launch an investigation.

According to Gaceta UNAM, the university president apologized to honest candidates, acknowledging that they must now study and retake the exam without having violated any rules. Despite this inconvenience, he affirmed the measure as "necessary to ensure accuracy and fairness in admissions". The university has not yet disclosed the specific cheating methods identified.

The original exam's multiple-choice format, rather than essay-based, made detecting AI use, such as copying and pasting entire answers, very difficult. Beyond AI, it is possible candidates used unauthorized materials, knew the questions in advance, or employed other cheating tactics. The New York Times reported last week that various "cheating tricks" circulated widely on social media before the exam. Candidates were instructed to place secondary screens out of webcam view to consult ChatGPT or other AI models, wear tiny earphones hidden under their hair, or hire proxies to sit outside the camera's angle.

In preparation for the online exam, UNAM implemented stringent security measures. Candidates installed LockDown Browser software to disable printing, copying, messaging, website access, or opening other applications. Concurrently, the university integrated AI algorithms to analyze webcam data, identifying proxies, detecting candidates using phones or earphones, or leaving the camera's field of view. Additionally, one online proctor monitored every 150 candidates, receiving AI alerts about unusual activities.

Despite these efforts, the technological measures did not yield the expected effectiveness. Before releasing the scores, the system only detected and invalidated 2% of exams violating regulations. The university admitted that "it is highly probable a large number of candidates received assistance" during the exam.

UNAM was established in the 16th century and granted autonomy in 1929. Since then, it has been considered a symbol of Mexico and a center for political and social movements, according to CNN. Its main campus was recognized as a World Cultural Heritage site by UNESCO in 2007.