Plagiarism is the act of presenting someone else’s words, ideas, data or creative work as your own without proper attribution. It is a breach of research integrity because it misrepresents who is responsible for a contribution and removes the credit owed to the original author. Plagiarism can be deliberate or careless; both are taken seriously in scholarship.
The defining feature is the missing or inadequate acknowledgement. Using another person’s work is normal and necessary in research; doing so without crediting them is what makes it plagiarism. The remedy is therefore straightforward in principle: accurate, complete citation.
Why plagiarism breaches research integrity
Research is cumulative. Each contribution is supposed to declare what it owes to prior work so that credit, accountability and verifiability remain intact. The Committee on Publication Ethics (COPE) frames plagiarism as a serious form of publication misconduct precisely because it corrupts the record of who did what. When attribution fails, readers cannot trace a claim to its source, the original author is denied recognition of their authorship contribution, and trust in the literature erodes.
The main types of plagiarism
Plagiarism is not a single behaviour. Recognising its forms is the first step to avoiding them.
| Type | Description |
|---|---|
| Verbatim (direct) plagiarism | Copying text word for word without quotation marks or a citation. |
| Mosaic / patchwork plagiarism | Interweaving copied phrases from one or more sources with your own words, without attribution. |
| Paraphrasing without attribution | Restating someone’s idea in your own words but omitting the citation, leaving the idea uncredited. |
| Self-plagiarism / text recycling | Reusing your own previously published work without disclosure (covered in depth separately). |
| Contract cheating | Submitting work produced by someone else — paid or unpaid — as your own. |
Verbatim and mosaic plagiarism
Verbatim plagiarism is the most recognisable form: lifting sentences directly. Mosaic plagiarism is subtler and often unintentional — it happens when a writer stitches together fragments of source text with light edits, never quite quoting and never quite citing. Both are detectable and both are misconduct.
Paraphrasing without attribution
Changing the wording does not remove the obligation to cite. If the underlying idea, structure or finding came from a source, the source must be credited even when no words are copied. This is one of the most common honest mistakes among new researchers.
Self-plagiarism and contract cheating
Reusing one’s own prior text without disclosure — self-plagiarism — can mislead readers about what is new. Contract cheating, where work is outsourced and submitted as one’s own, is among the most serious breaches because it falsifies the entire basis of attribution.
How proper citation prevents plagiarism
Most plagiarism is prevented by the same disciplined habits that produce good research outputs:
- Quote and cite direct text. Place copied wording in quotation marks and add an in-text citation pointing to a full reference entry.
- Cite paraphrased ideas. Even fully reworded ideas need a citation if the substance came from a source.
- Keep meticulous notes. Record where every fact, quotation and figure came from as you read, so attribution is never reconstructed from memory.
- Disclose reuse of your own work. Cite your earlier publications just as you would another author’s.
The mechanics of doing this well — pairing an in-text marker with a complete reference — are explained in what a citation is and our guide for authors.
The role of similarity-detection tools
Text-matching services such as Turnitin and iThenticate compare a submission against large corpora and report overlapping passages as a similarity score. These tools identify matching text; they do not, by themselves, determine intent or whether a match is properly attributed. A high similarity score may reflect correctly quoted and cited material, while genuine plagiarism of ideas can produce a low one. They are an aid to human judgement, not a verdict.
Frequently asked questions
Is paraphrasing plagiarism?
Paraphrasing is not plagiarism when the source is cited. It becomes plagiarism when you restate someone’s idea in your own words but omit the citation, because the idea remains uncredited even though the wording has changed.
Can you plagiarise your own work?
Yes. Reusing your own previously published text, data or figures without disclosure is known as self-plagiarism or text recycling. It can mislead readers about what is original, which is why prior work should be cited and reuse disclosed.
Does a low similarity score mean there is no plagiarism?
No. Similarity-detection tools flag matching text, not stolen ideas. Plagiarism of concepts or findings can be paraphrased into a low score, while properly quoted and cited passages can raise a score legitimately. The tools support human judgement rather than replace it.
What body sets standards on plagiarism in publishing?
The Committee on Publication Ethics (COPE) provides widely adopted guidance on plagiarism and other forms of publication misconduct for editors and publishers. For standardised definitions of related terms, see the CASRAI dictionary.