AI Detector for Discussion Posts
Updated
An AI detector for discussion posts has a built-in problem: many forum replies in online courses are short. This detector needs at least 300 words, so it can check longer initial posts but not one-paragraph replies. Here is how to use it on course discussions, and what to do when posts are too short.
Limitations: Every result is a probability that can be wrong, not proof of how something was written. How results can be wrong →
3 free scans in total, shared across all five tools (not per day or per month). No signup needed to start.
What an AI Detector for Discussion Posts Can Check
- Initial posts: main posts that answer the week's prompt are often long enough (300+ words).
- Replies: short replies to classmates usually aren't; the check won't run on them.
- One student's posts together: combining a student's own posts into one text is possible, but the score then describes all of them, not any single post.
- English only: the site supports English only.
Signs That Matter More Than a Score
In discussion boards, context often tells you more than a detector: a post that doesn't engage with the readings, ignores what classmates said, or uses a very different voice from the student's other work.
Discussion prompts that ask for personal experience, a specific page reference or a reply to a named classmate are harder to answer with generic AI text, and easier to grade.
Fair Use in Online Courses
Share your AI policy with students at the start of the course, and say how you will handle concerns. If a post seems AI-written, ask the student to explain or extend their point before drawing any conclusion.
Remember that detectors can flag human writing, and that non-native English writers have been shown to be flagged more often in research on GPT detectors.
Designing Prompts That Need Real Engagement
Prompts that ask students to connect the week's reading to their own work, quote a specific passage, or answer a named classmate's point make generic replies easy to spot without any tool.
Rotating prompt formats, such as a short audio reply or a diagram with a caption, also gives students more ways to show their understanding.
Frequently asked questions
No. The detector needs at least 300 words; short replies don't give it enough text for a meaningful result.
Yes, if they are from the same student, but the score then reflects all of them together, not one post.
No. There is no LMS integration; copy the text into the detector.
Ask the student to explain or extend their post. Use the score, if at all, as one signal, never as proof.
Sources
- GPT detectors are biased against non-native English writers (Liang, Yuksekgonul, Mao, Wu, Zou) (arXiv 2304.02819, read on )