In the era of digital education and online publishing, plagiarism detection software plays a crucial role in maintaining academic and editorial integrity. However, even the smartest technology sometimes flags content as plagiarized when it isn’t — especially when it comes to properly quoted material. Writers, researchers, and students often find themselves caught in frustrating loops explaining to software (and their institutions) that citing sources correctly does not equal copying. Let’s dive into the top plagiarism detectors known to mislabel quotations and how users have successfully contested these reports.
TL;DR (Too Long; Didn’t Read)
Top plagiarism scanners like Scribbr, Turnitin, Unicheck, and Grammarly have occasionally mistaken properly cited quotations as plagiarism. This is due to their algorithm reading exact matches without always verifying context. Authors have successfully proven originality by appealing to support, using citation standards like APA, and submitting supplementary evidence. Understanding these errors can help writers better prepare documents to reduce false positives.
Top 4 Plagiarism Scanners That Incorrectly Flagged Quotes
- Scribbr
- Turnitin
- Unicheck
- Grammarly
1. Scribbr: Accurate but Unforgiving
Scribbr is well-regarded for academic work, primarily among university students writing theses and dissertations. Its strength lies in its extensive database, which covers millions of scholarly and online sources. However, users have reported that Scribbr frequently flags properly quoted material, even when double quotation marks and citations are present.
The problem stems from its strict match-based detection. The AI reads the text verbatim and highlights identical sections found online, regardless of citation. For example, one student quoted a passage from a peer-reviewed journal and cited it using APA format. Still, Scribbr flagged 18% similarity, including the quotation as a major source of concern.
To resolve this, the student provided screenshots of the source citation and used Scribbr’s internal review support to explain the context. The support team eventually acknowledged the quotation was acceptable and offered a revised report.
2. Turnitin: Widely Used, Sometimes Overzealous
Turnitin is perhaps the most used plagiarism detection tool in academia. It has robust databases including student paper archives, online content, and journals. Despite this advantage, Turnitin has a reputation for being “overinclusive.” It frequently flags quoted material even if it’s embedded within proper citation methods.
One graduate student faced a 25% similarity score on Turnitin for a paper that included seven properly cited quotations. Although she had adhered strictly to APA formatting guidelines, Turnitin highlighted each quotation as a copied segment.
The student approached her professor with annotated copies showing where quotes were used and how they adhered to university guidelines. With professor support, Turnitin’s flagged areas were overridden by the institution as acceptable, not actual plagiarism.
3. Unicheck: User-Friendly but Limited Context Capability
Unicheck has gained popularity in both educational and corporate settings due to its simplicity and real-time scanning. While it provides a clean interface and easy-to-read reports, it sometimes lacks the capability to differentiate between unoriginal content and quoted text.
An author working on a whitepaper faced a 20% match rate that heavily leaned on his use of block quotes. Each source was attributed correctly, but the system flagged the block quotes — specifically because the quotation length was significant, even though it was academically justified.
After contacting Unicheck’s customer service, the user was advised to adjust block quotes into paraphrased summaries. Instead, the author enclosed detailed commentary with each quotation to show academic purpose. A second scan brought the match score down to 8%, showing how additional author voice helps avoid red flags.
4. Grammarly: Great for Grammar, Tricky for Attribution
Although Grammarly is primarily known as a grammar and style checker, it has introduced a plagiarism check feature. For shorter essays and blog posts, it works well. However, Grammarly’s plagiarism engine doesn’t yet handle quotations robustly.
A journalist conducted an article citing multiple policy analysts and research centers. Grammarly flagged 15% of the text as copied, mainly because many of the cited materials were common phrases or definitions that exist across multiple platforms.
Upon rephrasing some definitions and incorporating more interpretation around the quotes, the flagged percentage dropped. Grammarly does not currently allow users to “exempt” quotations manually, so the best approach is to ensure surrounding original commentary is present.
How Authors Proved Originality
Despite the automatic nature of these scanners, several writers, students, and professionals have proactively challenged and fixed their reports. Here’s how:
- Documenting Citations: Screenshots or citations from trusted source databases can serve as evidence during reviews.
- Direct Communication: Contacting support teams or professors for individualized assessment makes a difference.
- Adding Commentary: Instead of long block quotes, combining quoted material with original thought lowered match scores.
- Formatting Quotes Properly: Using quote marks, spacing, and the correct style guide (APA, MLA, Chicago) helped reviewers understand the quoted intent.
Is the System Flawed or Just Incomplete?
All four scanners rely on pattern recognition and database matching. They often focus on what is matched rather than why. This limitation stems from their algorithmic base — code doesn’t always understand context the way humans do.
This doesn’t mean plagiarism scanners are broken, but rather they’re designed to be hyper-vigilant. Developers prioritize catching every possible duplication, even at the cost of a few false positives. This is why human review is essential in tandem with automated reports.
Best Practices to Avoid False Positives
- Use shorter quotes and summarize when possible.
- Always attach a reference list or bibliography with clear formatting.
- Double-check styling guides to ensure quotations follow academic standards.
- Save note annotations beside quotes to discuss purpose and incorporate your analysis.
Conclusion
While plagiarism scanners provide a valuable shield against academic dishonesty, they are far from perfect. Mislabeling proper quotations is a common, yet correctable, flaw. By understanding the algorithms behind these tools and preparing texts with clarity, authors can maintain credibility without losing their writing voice to system errors.
FAQ
- Q: Can plagiarism scanners differentiate between quotations and plagiarized content?
A: Not always. Most rely on word-match algorithms and don’t fully interpret surrounding context, especially if you don’t provide enough commentary. - Q: What should I do if my properly cited quotes are flagged?
A: Include citations, provide context, and if necessary, submit a review request to the scanner’s support team or your academic advisor. - Q: Is it better to paraphrase or quote directly?
A: A mix is best. Paraphrasing lowers similarity rates; however, direct quotes are acceptable if cited well and used sparingly. - Q: Can I edit a report in tools like Turnitin or Scribbr?
A: Users cannot directly edit a report, but they can request analysis, submit new versions, and provide supporting annotations to institutional reviewers. - Q: Are these issues more common with free vs. paid plagiarism tools?
A: Even paid tools are affected. The issue lies in the detection mechanism rather than pricing tier. However, paid versions often offer customer support to resolve these anomalies.
Published on December 13, 2025 under .
