Cornell University switches to oral exams to stop students from using ChatGPT to write homework

Cornell professor Chris Schaffer introduced oral defense exams last semester as a direct response to ChatGPT — students must now explain their work aloud to an instructor, making it impossible to submit AI-generated assignments without detection.

Unlike traditional written homework that can be generated by large language models (AI systems trained to write text), an oral exam forces real-time conversation where instructors can ask follow-up questions and watch whether a student actually understands the material or just copied an AI's answer.

For students: submitting ChatGPT-written work is no longer a viable shortcut in classes using oral exams — you now need to genuinely learn the material. For educators: this signals a shift away from assignments that can be outsourced to AI, forcing a rethink of how grades actually measure student knowledge.

This approach is spreading to other universities as institutions recognize written assignments alone no longer prove learning in the ChatGPT era, but oral exams remain time-intensive and difficult to scale to large lecture halls.