Turnitin is a similarity detection tool, not a plagiarism editor. Its purpose is to highlight text that matches existing sources so that authors can revise their writing to meet academic integrity standards. Reducing similarity does not mean hiding plagiarism; it means correctly paraphrasing, citing sources properly, and writing original content based on understanding.
The first and most important step is to understand the Turnitin similarity report. Turnitin highlights matched text and shows the sources from which the content is similar. High similarity often comes from copied sentences, reused phrases, improper paraphrasing, excessive quotations, or common technical descriptions copied from base papers.
To reduce similarity, the matched text must be rewritten conceptually, not cosmetically. Simply changing a few words, replacing synonyms, or reordering sentences does not significantly reduce similarity and is easily detected. Instead, the idea should be fully understood and rewritten using a different sentence structure, different flow, and different vocabulary while keeping the original meaning intact.
Another effective approach is to merge information from multiple sources into a single original explanation. When the same idea appears in many papers, writing a synthesized version in your own words with multiple citations reduces similarity more effectively than rewriting one source at a time.
Proper citation also plays a key role. Even well-paraphrased text must be cited. If a paragraph discusses ideas from one source, the citation should be placed clearly at the end of that paragraph. Missing citations can cause Turnitin to flag content as problematic even if the wording is different.
Direct quotations should be avoided in research articles, especially in engineering and science journals. Quotations increase similarity scores and are discouraged by most SCI and Scopus journals. If a definition or statement must be quoted, quotation marks and proper citation must be used, but this should be done sparingly.
Another common source of similarity is the methodology and background sections, where many authors reuse standard descriptions. To reduce similarity in these sections, write procedures in your own experimental context, use active voice, and focus on what you did rather than copying generic explanations. Customizing descriptions to your dataset, tools, parameters, and workflow significantly lowers similarity.
Figures, tables, equations, and original diagrams help reduce textual similarity because they convey information without copying text. However, captions must also be written originally and should not be copied from other sources.
After revising the manuscript, it should be rechecked using Turnitin to verify the reduction in similarity. The process may need to be repeated multiple times. Acceptable similarity levels vary by journal, but generally a similarity index below 10 to 15 percent, excluding references and common phrases, is considered safe.
It is important to note that reducing similarity should never involve techniques such as hiding characters, using invisible symbols, translating text back and forth, or manipulating formatting. These practices are unethical, easily detected, and can lead to rejection or blacklisting by journals.
In conclusion, reducing similarity using Turnitin is achieved through genuine understanding, strong paraphrasing, proper citation, synthesis of multiple sources, and original academic writing. When done correctly, Turnitin becomes a guide for improving writing quality rather than just a similarity checker.