Plagiarism is presenting someone else's words or ideas as your own, whether on purpose or by forgetting a citation. Similarity checkers find the overlaps; understanding what they measure lets you fix a text properly rather than just lowering a number.
The forms it takes
Direct copying is the obvious case. Mosaic plagiarism stitches together phrases from several sources with small changes. Paraphrasing without attribution borrows the idea while changing the words. Self-plagiarism reuses your own earlier work without saying so — a problem in academic and publishing contexts.
How a similarity check works
The checker splits your text into overlapping fragments and compares them with an index of web pages, publications and documents. Matching fragments are grouped into passages and linked to their most likely source. The similarity score is the share of your text covered by such passages.
Reading the report
A high score is not automatically a problem: quotations, bibliographies and common expressions all match. Open each highlighted passage and ask whether it is quoted and cited. The passages that are not are the ones to fix.
Fixing a text
Either quote the passage with quotation marks and a citation, or restate the idea in your own structure and cite the source. Changing a few words is not enough — the structure of the sentence must be yours.
Citing correctly
Follow the style your institution or publisher requires (APA, MLA, Chicago, Harvard…). Whatever the style, a citation must let the reader find the source: author, title, year and location.
Checklist
- Check the final version, not an early draft
- Open every highlighted passage
- Quote or restructure, then cite
- Keep the PDF report with your submission
- Re-run the check after the fixes
Treat the checker as a proofreader for attribution: it points at the passages, you decide how to credit them.