How to Reduce Plagiarism in Your PhD Thesis — Similarity Score and AI-Content Check Guide

A thesis can be finished and still be blocked by one number: the similarity score. Most universities set a limit, and scholars often discover too late that sections they wrote themselves are flagged. Here is how similarity checks really work and how to bring the score down honestly — by rewriting, not by tricks.

Why a Genuine Thesis Still Shows High Similarity

1. Literature review — standard phrasing and close paraphrasing of sources
2. Methodology — repeated descriptions of well-known methods and equations
3. Your own papers — text reused from your published work counts as overlap
4. Definitions and standard terms — common phrases that match many documents
5. Poor paraphrasing — changing a few words, not the sentence structure
6. AI-assisted drafting — text that wasn't reworked into your own style

What Is Usually Counted and What Often Isn't

Rules differ by university and tool (Turnitin, iThenticate, Urkund/Ouriginal and others). Many institutions let you exclude the bibliography, quoted text, and sometimes small matches, and some exclude your own earlier publications. Always confirm your university's exact policy and threshold before you start editing.

Step 1 — Run a Check Early, Not at the End

Check each chapter as you finish it. Fixing one chapter at a time is far easier than rewriting a full thesis in the last week.

Step 2 — Read the Report, Not Just the Percentage

The report shows which sources match and which sentences. A few large matches usually cause most of the score, so fix those first.

Step 3 — Rewrite at the Idea Level

Weak: swapping words for synonyms. Strong:

1. Read the source and close it
2. Write the idea in your own words and structure
3. Combine ideas from several sources into your own comparison
4. Cite the source properly

Synonym-swapping often still gets flagged and can read awkwardly.

Step 4 — Handle Your Own Published Papers

If your thesis includes material from your papers, follow your university's rules on acknowledging and declaring it. Where overlap must be reduced, rewrite the section for the thesis context.

Step 5 — Quote and Cite Correctly

Use direct quotes only where needed, in quotation marks, with citations. Check that every claim and figure has a reference.

About AI-Content Checks

Some universities and journals now run AI-writing detection. These tools are not perfectly reliable, but heavily AI-drafted text can be flagged and, more importantly, may not reflect your own understanding. Write your own analysis and arguments, use tools only as permitted, and be ready to explain every paragraph in the viva.

Final Pre-Submission Checklist

1. Similarity score within your university's limit
2. All sources cited and listed in references
3. Own-paper overlap declared as required
4. Figures, tables, and quotes properly credited
5. A final full-thesis check after all edits

Where This Fits

Plagiarism clearance is one stage of the full journey. See our complete PhD research assistance, thesis writing services, and research paper writing and publication services.

Need Expert Help With Your PhD?

If your thesis or paper is above the allowed limit, we can review the report, rewrite flagged sections at the sentence and paragraph level, and recheck so it is ready for submission. The rewriting stays faithful to your research and your meaning.

Talk to us on WhatsApp or explore our M.Tech & PhD Assistance services.