AI homework tools cut exam scores by 20%, study of 26,000 Chinese students finds

AI homework tools cut exam scores by 20%, study of 26,000 Chinese students findsResearchers in Sweden and Hong Kong say students may experience a deceptive sense of fluency – AI makes tasks feel effortless3-MIN READ3-MIN0ListenPublished: 9:00am, 14 Jul 2026Updated: 9:03am, 14 Jul 2026Artificial intelligence boosts homework scores but cuts exam results by 20 per cent, and this “brain drain” effect takes two years to fully emerge, a new study has found.Generative AI is rapidly transforming classrooms as much as workplaces, with students increasingly turning to chatbots to draft essays and solve problem sets. But is the technology a personalised tutor or a slow-acting cognitive poison?Research by scholars from Stockholm-university" class="entity-link entity-organization" data-entity-id="153875" data-entity-type="organization">Stockholm University and the University of Hong Kong, who tracked the academic performance of more than 26,000 middle school and high school students across a county in central China over 30 months, offers a quantified answer.02:33What is the gaokao, China’s most important exam?From September 2022 to June 2025, the team tracked homework grades, completion times, monthly test scores and entrance-exam results. By comparing AI users with non-users, they found a clear gap: AI boosted short-term efficiency but harmed long-term learning.