Mexico City, Mexico — The National Autonomous University of Mexico (UNAM) will make thousands of applicants re-take their undergraduate entrance exam after controversy over suspected AI use.

University officials opened an investigation after suspiciously high results in the first round of testing, which took place online in May and June. 

The announcement has stirred controversy among applicants and students given the high stakes application process for one of Mexico’s most competitive universities. 

This was the first year the entrance exam was held online, a move the university described as intending to improve access for students outside the capital city.

But when the results were released on July 17, university officials detected several irregularities.

One of the statistics flagged by the reviewing committee was that between 2021 and 2025, approximately 3.5% of students scored 100 or more correct answers. This year, that percentage had risen to 16.3%.

The AI system the university used to monitor test-takers online also flagged cases of phone use, help from other people and identity substitution. 

A technical committee set up on July 27 to look into the admissions process found the numbers raised significant doubts about testing integrity. 

Around 2% of the 158,727 exams taken over three weekends in May and June were nullified and UNAM has filed a formal complaint with authorities.

The technical committee also recommended that the test be retaken in person.

The new exam will be required for students who were already notified they’d been accepted, plus rejected applicants whose scores matched or beat the lowest passing score between 2021 and 2025.

UNAM hasn’t said when or where the new test will happen, although the institution confirmed it will be a pen and paper, in-person exam this time. 

Rector Leonardo Lomelí backed the measures but apologized to students who had already been told they were accepted. “I offer an apology to the applicants who were preliminarily admitted, but this measure is necessary to guarantee transparency, provide certainty, and ensure access to the university is equitable,” he said in a press conference this morning.

Student reaction has been mixed; some applicants want the whole exam repeated while others say the original results should stand. Earlier this week dozens of them showed up on the main campus to protest.

Featured image description: Main library at the Universidad Nacional Autónoma de México (UNAM).

Featured image credit: Wikimedia Commons.