What is incremental plagiarism?
Incremental plagiarism is failing to credit specific parts of a work that is otherwise your own. Most of the speech or essay is original, but a quotation, a statistic or a paraphrased idea from someone else appears without a citation. The term comes mainly from public speaking courses.
An “increment” is a small part. That is the point of the name: the problem is not the whole work, only certain pieces of it. An open public speaking textbook describes it as plagiarism that occurs “when most of the speech is the speaker’s original work, but quotes or other information have been used without being cited”.
What needs credit
The companion site for Stephen Lucas’s The Art of Public Speaking says incremental plagiarism happens when a speaker does not give credit for specific quotations and paraphrases borrowed from other people. In practice, three kinds of material get missed.
| What you borrowed | What it needs |
|---|---|
| Someone’s exact words | Quotation marks and a citation. In a speech, say that you are quoting and name the speaker. |
| Someone’s idea in your words | A citation. No quotation marks, because the wording is yours. |
| A fact, figure or finding | A citation, unless it is common knowledge that any reader could check anywhere. |
Before and after examples
Both examples are invented, including the authors and the numbers. The highlighted parts are the borrowed material that was left without credit.
In a speech: an uncredited statistic and quotation
Before. I started walking to class in my first year, and it changed my mornings. Students who walk for twenty minutes before a lecture remember a third more of it. And honestly, movement is the cheapest study aid we have.
After. I started walking to class in my first year, and it changed my mornings. A 2023 study by the education researcher Dr. Ines Marlow found that students who walked for twenty minutes before a lecture remembered a third more of it. In her words, “movement is the cheapest study aid we have.”
The story is still the speaker’s own. The only change is that the audience now knows which part is Marlow’s finding and which sentence is her wording.
In an essay: an uncredited paraphrase
Before. My town closed its last bookshop in 2022, and I think we lost more than a shop. Small bookshops work as informal community centres, where people meet without needing a reason to be there. That is exactly what I saw on Saturday mornings.
After. My town closed its last bookshop in 2022, and I think we lost more than a shop. Hale (2020) argues that small bookshops work as informal community centres, where people meet without needing a reason to be there (p. 14). That is exactly what I saw on Saturday mornings.
The middle sentence was already in the writer’s own words. It still needed a citation, because the idea came from Hale.
Incremental vs patchwork vs global plagiarism
Public speaking courses teach these three together. They differ in how much of the work is borrowed.
- Incremental. The work is mostly yours. Specific borrowed parts are not credited.
- Patchwork. The work is built from pieces of a few sources, stitched together. Writing guides often call this mosaic plagiarism.
- Global. The whole work is taken from one source.
Two more terms overlap with it. When the uncredited part is copied word for word, that part is also direct plagiarism. When it is a paraphrase that stays too close to the source’s sentence, it is also patchwriting. Our guide to the types of plagiarism shows how they all fit together.
How it shows up in a similarity report
Incremental plagiarism usually produces a low overall score, which is why it is easy to overlook.
- A few isolated matches. One sentence here, one there, with long stretches of unmatched text between them.
- A different source for each match. The matches do not point to one document.
- No citation beside the match. This is the detail to look for.
So read every match, not only the percentage. A checker compares wording. A paraphrase in fresh wording or a bare statistic may not be highlighted at all, so go through your notes as well and confirm that each borrowed idea has its source. A match is a signal for review, not proof of plagiarism.
How to avoid incremental plagiarism
- Write the source next to every note. Author, year and page, at the moment you take the note. Most missing citations start as a note with no source.
- Mark exact words straight away. Put quotation marks around anything you copy, so you can tell later what was a quote and what was your summary.
- Cite as you draft. Do not leave “add citation” for the end. Put in the author and year when you write the sentence.
- For a speech, write the credit into your outline. Decide the exact words you will say, such as “according to a 2023 study by…”. A source listed only on your last slide does not credit the sentence where you used it.
- Do a final source pass. Read the draft once, asking of each claim: did I work this out myself, or did I read it somewhere?
- Check the draft. Run a plagiarism check with Plagiarism Checker Plus. The report links each matching passage to its source, so you can see which sentences still need quotation marks or a citation.
If you are not sure how far to reword a source, read our guide on how to paraphrase without plagiarizing.