You ran your paper through a plagiarism checker and got a similarity score of 28%. Panic. You rewrote paragraphs, swapped synonyms, even deleted a quote you liked. Then you submitted — and the official report came back at 9%. Same paper. What happened?
Most likely, your instructor had Turnitin's exclusion settings turned on: "Exclude bibliography" and "Exclude quoted material." These quiet, instructor-side options can slash a similarity score by 10 to 20 points — and most students have never heard of them. Here's the honest truth about what these settings do, why you can't toggle them yourself, and what you can do to make them work in your favor.
When an instructor creates an assignment in Turnitin, they control how the similarity report is generated. Three settings matter most:
These are assignment settings, not student settings. The choice lives on your instructor's side of the dashboard.
A Turnitin similarity score is a percentage: matched words divided by total words. References and quotations are dense with matchable text — your entire bibliography is, by design, copied formatting. When an instructor enables exclusions, those chunks leave the numerator while the denominator stays the same. The score drops instantly, and nothing about your writing changed.
This is why two students with identical papers can get different scores in different courses: one instructor enabled exclusions, the other didn't. It also explains why your own pre-check might show a higher number than the official report — many third-party checkers match your bibliography aggressively, while your instructor's report excluded it. If you're using a checker that gives you an official Turnitin similarity report, like the one from TurnPro AI, you'll see the score as Turnitin itself generates it — but the instructor-side exclusion toggles still belong to your instructor.
Let's be direct: there is no button you can press to exclude your bibliography or quotes. These toggles exist only in the assignment creation and editing screens that instructors see. Some students search forums for hacks or tricks to force exclusions — don't waste your time. There are none, and trying to game the report (like hiding references in images) is an academic integrity risk you don't need.
But "you can't change the settings" is not the same as "you can't do anything." Here's what actually helps.
1. Ask your instructor what settings they use. This is the single most useful question you can ask: "For our Turnitin submission, are bibliography and quoted material excluded?" Most instructors will tell you — it's not secret. Knowing the answer tells you exactly how to interpret your score and where to focus.
2. Format your reference list cleanly. Exclusion filters work best when Turnitin can recognize the bibliography section. Use your required citation style consistently, label the section clearly ("References" or "Bibliography"), and keep it in the same document. A messy, inconsistent reference list is harder for the filter to identify.
3. Use real quotation marks for direct quotes. The "exclude quoted material" filter detects text wrapped in standard quotation marks. Curly quotes, indent-only formatting, or block quotes without quotation marks may not be caught. Follow your style guide (APA, MLA) precisely — proper formatting isn't just about grades, it's about clean similarity reports.
4. Cite every quote properly. Exclusion isn't permission to over-quote. Many instructors and institutions have policies on excessive quotation even when it's cited. Paraphrase where you can, quote where the exact wording matters.
5. Pre-check your paper before submitting. Run a non-repository similarity check — one that doesn't store your paper in Turnitin's database — so your draft never counts as a prior submission. If your checker lets you view the report, look at where the matches are: a cluster of matches in your references or inside quotation marks tells you the score will likely drop once your instructor's exclusions kick in. Matches scattered through your own paragraphs tell you where to genuinely revise.
6. Keep your reference list proportionate. Exclusion removes the bibliography from the score, but instructors still read it. A reference list longer than the paper's body, or dozens of sources you never actually discuss, looks padded and invites scrutiny. Cite sources you genuinely used — quality over quantity always reads better.
No. Exclusion settings are controlled by the instructor when the assignment is created. Students have no access to these toggles in the student submission view.
It varies by paper, but excluding the bibliography commonly removes 5–15 percentage points, and excluding quoted material removes more for quote-heavy work. Small-source exclusion filters out the low-level noise on top of that.
Your pre-check tool probably matched your bibliography and quoted passages fully, while your instructor's Turnitin report excluded them. This is normal — it means the settings are working as intended, not that either report is wrong.
Yes — it's a legitimate academic question. Knowing whether bibliography and quotes are excluded helps you interpret your report and focus your revision on matches that actually matter.
Turnitin's exclusion settings aren't a loophole — they're how the tool is designed to work. Bibliographies and properly cited quotes are legitimate parts of academic writing, and instructors exclude them so the report highlights what actually matters: your own uncredited matches. You can't flip these switches yourself, but you can format your references cleanly, quote properly, ask your instructor what settings are on, and always pre-check your draft with a non-repository check before the real submission. A quick scan with an official Turnitin similarity + AI report from TurnPro AI — one that never stores your paper — shows you where your matches really sit, so you can submit with confidence instead of anxiety.