Mexico's top university voids admissions after mass cheating on first online entrance exam

Mexico's National Autonomous University of Mexico (UNAM), the country's most prestigious institution, has detected widespread cheating in the online entrance exam it introduced this year for the first time, prompting the university to void the results and require in-person retests for admitted applicants and other high scorers.

UNAM's technical committee said in an analytical report Friday that it had invalidated the results of roughly 2 percent of the approximately 158,000 examinees for cheating, and recommended that admitted applicants and those who scored above a certain threshold — even if they did not pass — sit an in-person "verification exam," according to local media including El Universal and Yonhap.

The university accepted the committee's recommendation and announced it would hold in-person retests. Applicants who had already received acceptance letters will have their admissions placed on hold pending the retest. High-scoring applicants who exceeded the passing mark for their chosen department in any of the past five years but were not admitted will also be given the opportunity to retest.

UNAM Rector Leonardo Lomelí apologized to applicants who had passed legitimately but must now sit the exam again, calling the retest "an unavoidable measure to ensure the credibility of the examination and guarantee equal access to admission opportunities."

He added that the abnormally high distribution of correct answers in the online exam had led him to conclude the situation needed to be corrected immediately.

The entrance exam was administered online over three consecutive weekends in May and June. Shortly after results were released in mid-July, however, anomalies — including a sharp surge in high scores — were detected, and the university suspended new student enrollment on July 24.

In the interim, the university conducted a detailed analysis of exam responses using an AI-based proctoring system cross-checked by faculty, and found that smartphone use during the online exam, assistance from outside parties and proxy test-taking had been widespread.

Data collected from 2021 to 2025 showed that an average of about 3.5 percent of examinees answered 100 or more of the 120 questions correctly; this year that figure jumped to 16.3 percent. The share of top scorers who answered 110 or more questions correctly jumped roughly sixfold — from an annual average of 0.9 percent to 5.5 percent this year.

When the university conducted a preliminary in-person test on a group of examinees suspected of cheating, a significant number scored markedly lower than they had on the online exam. Rector Lomelí said of the findings: "Shortcuts and cheating cannot produce the talent the nation needs."

The decision to hold retests has sparked strong opposition. Protests for and against the move have been held daily outside the university's main building. Applicants who failed the original exam welcomed the decision, calling it a chance to "evaluate real ability, not tricks," while those who had been accepted pushed back, insisting their results were "the product of hard work" and that "honest applicants should not suffer because of cheaters."

With more than 20,000 incoming students affected, the university plans to announce the detailed schedule and venues for the in-person retests soon to minimize disruption to the academic calendar. Unlike South Korea, Mexico has no standardized national college entrance exam; universities typically administer their own individual entrance tests.