September 13, 2026 · The Decoder
Two-year study finds banning AI in classrooms hurts student performance
A law professor's two-year study compared students under a full AI ban, unguided AI use, and structured AI training. The group barred from using AI finished last in both years, contradicting the researcher's own initial assumption that unguided AI use would be more harmful than a ban.
Why it matters: This is one of the few longitudinal, real-classroom studies on AI-in-education policy rather than a one-off survey, and it undercuts the precautionary case for the blanket bans many schools have adopted. It gives a policy debate that has mostly run on anecdote some actual multi-year evidence to work with.