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

The widespread adoption of artificial intelligence in education is creating a significant paradox: while AI tools enhance homework efficiency, they demonstrably harm long-term learning, leading to a notable decline in exam performance. A comprehensive study tracking over 26,000 Chinese middle and high school students over 30 months reveals that generative AI use boosts homework scores but ultimately cuts exam results by approximately 20%.

Researchers from Stockholm University and the University of Hong Kong monitored students' academic progress from September 2022 to June 2025. Their findings indicate that AI use significantly improves homework completion speed and scores. Around 80% of the students reported using AI tools like Doubao, DeepSeek, ChatGLM, Ernie Bot, and Qwen. These students completed homework faster, reducing time from 64 to 45 minutes, and saw an 18% increase in homework scores.

However, this efficiency comes at a steep cost to deeper learning. Within six months, the monthly exam scores of AI-using students dropped by 20%. This negative effect, described as a "brain drain," becomes more pronounced over time. After two years, their performance on crucial entrance exams plummeted: the zhongkao (high school entrance exam) saw an 18% decrease, and the gaokao (National Higher Education Entrance Examination) results fell by 24%.

The study suggests that while AI can be a powerful tool for drafting essays and solving problems, its overuse may hinder the development of critical thinking and analytical skills essential for academic success. The findings raise important questions about the role of AI in education and the potential long-term cognitive consequences for students who rely heavily on these technologies.