Before a manuscript reaches the peer-review committee at an IEEE event, it must pass a strict, automated plagiarism check. IEEE utilizes the CrossCheck system (powered by iThenticate) to scan every submitted paper against a massive database of previously published works, websites, and institutional repositories.

If your similarity score is too high, your paper will face an immediate desk rejection. Understanding the exact thresholds IEEE uses is critical for a successful submission.

Here is a detailed breakdown of the acceptable plagiarism rates and how to ensure your manuscript complies with IEEE publishing standards.

The Overall Similarity Threshold

While individual conference committees have some discretion, IEEE has established strict baseline guidelines for overall similarity.

• The Safe Zone (Under 20%): A total similarity score of 20% or lower is generally considered safe. This indicates that the vast majority of the text is highly original. Any matches found in this range are typically standard academic phrasing, properly cited quotes, or methodology jargon.
• The Borderline Zone (20% to 30%): Papers falling into this range will trigger a manual review. The Program Chair will carefully examine the report to determine if the matched text consists of harmless boilerplate language or if it constitutes actual plagiarism.
• The Danger Zone (Over 30%): A score exceeding 30% almost always results in an automatic desk rejection. The paper will be returned to the author without being sent to peer reviewers.

The Critical Single-Source Limit

Many authors focus entirely on the overall percentage and fail to realize that the composition of that score matters just as much.

IEEE enforces a strict Single-Source Rule. Even if your overall similarity score is a perfectly safe 15%, your paper will still be rejected if 10% of that matched text comes from a single previously published article or website.

As a general industry standard, no single source should account for more than 5% of your total similarity score. A high match from a single source implies that a massive, continuous chunk of text was copied directly, rather than synthesizing multiple sources into your own original thought.

Navigating Self-Plagiarism

The most frequent reason experienced researchers fail the IEEE CrossCheck is self-plagiarism.

If you copy and paste the methodology section from a paper you published two years ago, the system will flag it as a match. IEEE scans its own digital library (IEEE Xplore) rigorously. Even though you wrote the original words, reusing them without proper citation is an ethical violation. If you are expanding a previous conference abstract into a full paper, you must completely rewrite the text or clearly cite your own previous work.

Best Practices for Lowering Your Score

If you run a draft check and find your score is dangerously close to the limit, take these steps to refine your manuscript:

• Rewrite the Literature Review: High similarity scores usually originate in the background or literature review sections. Instead of quoting previous studies directly, summarize their findings entirely in your own words.
• Avoid Over-Quoting: Engineering and computer science papers should rarely rely on direct, word-for-word quotes. Focus on paraphrasing the core concepts.
• Verify Submission Guidelines: Before finalizing your document, it is highly recommended to double-check the specific track requirements of your target event. Utilizing academic platforms such as uconf.com, icfp.net, call4papers.org, and academic.net allows you to confirm the exact submission policies and similarity limits required by top-tier organizers.