How teachers can check a student essay for AI

Most of the work of checking for AI happens before any essay comes in. A clear policy and a record of the writing process answer the question better than a detector score can on its own.

Before the assignment

Say what’s allowed. “No AI” means different things to different students. Is a grammar checker AI? Brainstorming with ChatGPT? Write down which uses are allowed and whether students need to say when they used them.

Ask for the process as well as the final essay. Collect an outline or a rough draft partway through, or have students write in Google Docs or Word so that version history exists. A short in-class writing sample early in the term also gives you something to compare later work against.

When an essay seems off

Start with the text. Does it mention the readings, class discussions, or examples from this course? AI drafts tend to answer the prompt in general terms that could fit any class. Check the quotes and citations; a source that doesn’t exist is stronger evidence than any style pattern.

Then look at the version history. In Google Docs, File > Version history > See version history lists saved versions with timestamps. A document where nearly all the text appeared at once, with little revision, is worth asking about. It isn’t proof on its own, since some students draft elsewhere and paste in their final text.

Reading a detector score

Scan the whole essay, not an excerpt, because short passages give any detector little to work with. Look at which sentences it highlights and read them yourself.

Keep the error rate in mind. In a 2023 Stanford study, seven detectors labeled, on average, 61.3% of human-written TOEFL essays by non-native English speakers as AI-generated (Liang et al., Patterns). A student writing in a second language is the student a detector is most likely to get wrong.

Know your tool’s cutoffs. Ours only says “Likely AI-generated” at 90% or higher and reports the middle range as “Inconclusive”. A middle score is a reason to look further. Are AI detectors accurate? explains why the cutoff matters so much.

Talking to the student

Start with questions about the work itself. Ask why they chose a particular example, where a source came from, or what they would change with more time. Most students can talk easily about writing they did themselves, and a student who can’t may simply be nervous, so one conversation settles less than it seems to.

If concerns remain, follow your school’s academic integrity process, and keep the drafts, the version history, and your notes from the conversation. Our guide for writers who’ve been falsely flagged as AI-written lists what a student will be asked to provide, which doubles as a list of what to look at.