Which AI detectors do teachers use?
Turnitin dominates because it's bundled into the LMS most schools already pay for — Canvas, Blackboard, and Moodle have no detector of their own. But it varies by campus, and you can find out exactly which one runs on your work: check the syllabus, the academic integrity policy, and the assignment's submission settings.
Why — the first-principles explanation
The useful move here isn't memorizing a list of vendors — it's realizing the answer is knowable for your specific situation, and that it's written down somewhere you can read.
Here's the structure. Detection reaches a teacher through one of three paths. The institutional path: the school licenses a service — almost always Turnitin, sometimes Copyleaks or another vendor — and switches it on inside the LMS. Instructure ships no native AI detector; Turnitin plugs into Canvas via the LTI 1.3 standard, and instructors configure per assignment whether to run full similarity and AI checks, lighter checks on drafts, or none at all. That per-assignment toggle is the reason two classes at the same school can behave completely differently. The individual path: a teacher pastes suspicious text into a free site like GPTZero or ZeroGPT. This leaves no institutional trace and follows no policy. The abstention path: schools like Vanderbilt that disabled detection outright in August 2023 and told faculty to use other methods.
Why the variation matters: your school's policy determines what a flag can actually do to you, and that's more consequential than which brand produced it. Some institutions treat an AI score as grounds for a conversation only. Others route it into a misconduct process. The peer-reviewed evidence — 14 systems found "neither accurate nor reliable," and roughly 61% of non-native English essays wrongly flagged across seven detectors — is why an increasing number of policies now explicitly forbid using a detector score as sole evidence.
So the honest answer to "which detector do teachers use" is: the one on your campus, which you can look up in about ten minutes, and possibly also a free website your instructor found on Google, which no policy governs and which nobody can audit.
An example that makes it click
Asking which AI detector teachers use is like asking which brand of smoke alarm apartments have. There's a common answer — most buildings use whatever the landlord installed everywhere — but yours specifically is a fact you can check by looking up at the ceiling.
And here's what actually matters: not the brand, but what happens when it beeps. In one building the alarm rings in your kitchen and you wave a towel at it. In another it's wired to the fire department and three trucks show up. Same alarm, same false positive, wildly different day. That's your school's academic integrity policy — and it's the document worth reading, not the detector's marketing page.
How to do it
- Read your syllabus. Instructors increasingly state their AI policy and whether submissions run through Turnitin or another checker — this is the fastest and most authoritative source for your class.
- Look up your school's academic integrity policy and any AI guidance page. Search your institution's site for 'AI detection' — many now state explicitly whether a detector score alone can support an allegation.
- Check the assignment's submission settings in Canvas, Blackboard, or Moodle. Turnitin-enabled assignments usually say so at submission, and instructors can choose whether AI checks run and whether you can see the report.
- Ask your instructor directly, in writing, before the deadline. 'Does this assignment run an AI check, and how do you use the result?' is a normal question and creates a record.
- If you're accused, ask which tool produced the score, request the full report, and ask what evidence exists beyond the number. Turnitin itself says the score requires professional judgment and context.
- Preserve your process evidence: keep drafts, use Google Docs or Word version history, and keep your notes and sources. That trail is stronger evidence than any score is against you.
Key facts
- Canvas/Instructure provides no first-party AI detector; Turnitin integrates via the LTI 1.3-based Turnitin Advantage Integration, with instructors choosing per assignment whether to run full similarity and AI checks.
- Turnitin's AI writing detection launched April 2023 and is bundled into tools Turnitin says are used by over 40 million students.
- Vanderbilt University disabled Turnitin's AI detector on August 16, 2023 and advised faculty to compare submissions to a student's prior writing, check for hallucinated sources, and talk to students directly.
- Turnitin activated AI detection for institutions with less than 24 hours' notice and no option to disable it at the time, per Vanderbilt.
- Peer-reviewed testing of 14 detection systems (December 2023) concluded the tools are neither accurate nor reliable.
- Across seven widely used detectors, about 61% of non-native-English TOEFL essays were misclassified as AI-generated versus near-perfect accuracy on U.S. eighth-grade essays (Liang et al., Patterns, July 10, 2023).
▶ The 60-second explainer (script)
Which AI detectors do teachers use? Mostly Turnitin — but here's the more useful thing: you can find out exactly which one runs on your work, in about ten minutes. Detection reaches a teacher through three paths. Path one, institutional: the school buys a service and switches it on inside the learning platform. Canvas doesn't have its own detector. Neither does Blackboard or Moodle. They plug Turnitin in. And instructors choose per assignment whether to run the AI check — which is why two classes at the same school behave completely differently. Path two, individual: your teacher gets suspicious and pastes your paragraph into a free website. GPTZero. ZeroGPT. That leaves no record and follows no policy. Path three: nothing at all. Vanderbilt disabled detection in 2023 and told faculty to compare your work to your earlier writing instead. So go look. Read the syllabus. Search your school's site for 'AI detection' policy. Check the assignment's submission settings. And ask your instructor in writing before the deadline — that creates a record. Because here's what actually matters: not which brand flagged you, but what your school lets a flag do. Some campuses treat a score as a reason for a chat. Others route it straight into a misconduct hearing. Same false positive, completely different year of your life. Read the policy, not the vendor's marketing page.
What authoritative sources say
People also ask
How do I know if my assignment is running an AI check?
Turnitin-enabled assignments in Canvas usually indicate it at the submission screen, and instructors control whether you can view the report. If it isn't stated, ask in writing before the deadline.
Can my teacher use a free detector instead of the school's?
Nothing stops them technically, and many do. It's the weakest form of evidence — free tools publish no serious false-positive testing, and pasting your work into a third-party site raises privacy questions your school may not have approved.
What if I'm falsely flagged?
Ask which tool produced the score, request the full report, and present your process evidence — drafts, version history, notes, search history. Turnitin's own guidance is that the score requires instructor judgment and context, not automatic conclusions.
Do all schools use detectors now?
No, and the trend has gone both ways. Some institutions expanded detection; others, including Vanderbilt, switched it off entirely after weighing false positive rates against enrollment size.
The same question, asked other ways
- Which AI checkers do teachers use?1,000/mo