A new study shows giving university students access to ChatGPT helped them produce higher-scoring, more expert-like work, but a separate critical-thinking intervention changed something the traditional grading rubric largely missed: the range and distinctiveness of their ideas. The randomized controlled trial, conducted by researchers at Bocconi University in collaboration with OpenAI Economic Research, involved 1,053 first-year undergraduates studying economics, management and finance. Students were split into four groups. One received access to ChatGPT Edu using GPT-4o, another completed training in causal reasoning, a third received both, and a control group received neither. They were then given 45 minutes to tackle the same real-world business problem, producing a short consultant-style recommendation for increasing awareness and use of their university’s merchandise among alumni. On the conventional performance measure, ChatGPT made the clearest difference. Students with GPT access scored an estimated 0.86 points higher on a five-point scale than the control group, whose estimated score was 2.09. Their recommendations were also more similar to those produced independently by three domain experts.