Evidence of AI’s Impact on Learning
Recently, the study “The Generative AI Learning Penalty: Evidence from Chinese Secondary Education,” authored by David Strömberg, Victor Lei, and Yanhui Wu, went viral after The Economist published data visualizations from the research paper. The working paper came out in June 2026 and uses data from approximately 27,000 Chinese students in grades seven to 12 to explore a straightforward question that has preoccupied me for several years: “How does self-directed use of generative AI affect cumulative learning over time in ordinary school settings?”
We will get into the details shortly, but here’s the headline summary of the results:
- Between 2023 and 2025, approximately 80 percent of all students started using generative AI. After just five months of use, approximately 50 percent of these students engaged in “full homework outsourcing,” meaning, they essentially stopped doing their homework independently and used AI instead.
- Over time, this caused significant learning loss as measured both on monthly closed-book tests and via the comprehensive high-stakes exams that China uses to determine high school and college placement for students. By the end of June 2025, overall student performance fell by 24 percent on the high school entrance exam and 18 percent on the college entrance exam—a massive decline.
- There is no evidence—none—of any corresponding learning benefit arising from students using AI. As such, the researchers state plainly that “our findings show that generative AI, which is likely to become a prevalent technology for education, has a substantial negative impact on student learning.” (My emphasis)
Put simply, we now have rigorous, empirical evidence on the real-world, long-term impact of students using AI. This research indicates that AI substantially harms learning for half of all students, what the researchers call the “Generative AI penalty,” and provides no discernible benefit to the other half. Again, by the time this study concluded, 50 percent of students using AI with regularity had fully outsourced their homework to generative AI. For these students, when at home, they just stopped thinking about their schoolwork.
In homage to Laurence Holt’s 5 Percent Problem, I have taken to calling this finding the “50 Percent Problem,” a conservative measure of the harm stemming from widespread AI adoption by students, rather than their failure to use it. I say it’s conservative because the researchers who conducted the study go further and suggest that “the negative effects on learning outcomes appear to be mostly driven by the 81 percent of AI-using students, who spend less time on homework than even the fastest non-AI student, receive high homework scores matching the capability of generative AI tools they are using, and yet very low exam scores.” Whatever number you prefer, however, the point is that a massive number of children are learning less because of AI: at least half and almost surely more than that.
As I’ve said repeatedly for several years, generative AI is a tool of cognitive automation. It’s both predictable and tragic that students are learning less because of it. This new empirical research provides us with a clear measure of the degree of this harm.
