As college students use ChatGPT to complete take-home tests, finish homework and write essays, professors are using blue books, or inexpensive, stapled exam booklets with a blue cover and lightly lined pages, to ChatGPT-proof the classroom. The advantage of blue books is that students can't use ChatGPT and have to instead write their essays by hand under a professor's supervision. Related: College Professors Are Turning to ChatGPT to Generate Course Materials. Elliott implemented a new system where students had to write essays in blue books for their final, and it worked so well that he plans to continue using blue books for the next academic year. More than 70% of college professors expressed concern about how ChatGPT could be used to cheat on assignments.