How to Check Your Thesis for Plagiarism Before Submission

#Why plagiarism checking matters before submission

Most universities run every submitted thesis through a plagiarism detection system before it reaches the examination committee. If the similarity report comes back with a high score, the thesis may be delayed, returned for revision, or in serious cases referred for disciplinary proceedings.

The critical point is that institutions run their check after you submit. By that point, the damage is already visible. Running your own check before submission gives you a chance to identify and correct problems while you still have time to fix them.

Plagiarism in a thesis is usually unintentional. The most common causes are closely paraphrased passages, missing quotation marks around direct quotes, incorrectly attributed ideas, and self-plagiarism from your own published papers or earlier coursework. None of these require bad intent to cause a problem on a similarity report.

#What plagiarism checkers actually detect

Understanding how detection works helps you interpret the results correctly.

#Direct copying

Any passage copied verbatim from a source without quotation marks will produce a high match. This is the most straightforward case. Even a single sentence copied from a source is flagged.

#Paraphrasing too closely

Changing a few words in a sentence while keeping the structure and most of the vocabulary is sometimes called mosaic plagiarism. Detection systems are trained to catch this even when no individual word matches exactly. Proper paraphrasing involves understanding an idea and rewriting it in your own words with a complete change of structure, not a synonym substitution pass.

#Self-plagiarism

If you have published papers, written reports for a previous course, or submitted chapter drafts to your institution as progress reports, those documents may already be in a database. Text from your own previous work used in your thesis without attribution is treated as self-plagiarism. The standard practice is to cite your own prior work and indicate which portions of the thesis are derived from it, following your institution's specific guidelines.

#Missing citations

If you describe someone else's idea, finding, or method without a citation, that passage will likely match the original source and appear as plagiarism even if you had no intention of claiming it as your own. Unattributed ideas are treated the same as copied text by automated systems.

#Step 1: Run a check early, not just at the end

The most valuable plagiarism check is not the one you run the night before submission. It is the one you run on each chapter as you finish drafting it.

Catching a heavily paraphrased passage in chapter two when you are still writing chapter three is manageable. Catching twenty instances of the same problem across eight chapters two weeks before your submission deadline is not.

Build plagiarism checking into your revision process rather than treating it as a final gate. Each completed chapter draft should go through a check before you move on.

#Step 2: Review the similarity report

A similarity report returns a percentage and a list of matched sources. Neither the percentage alone nor the list alone tells you whether there is a problem.

#High similarity is not always plagiarism

Similarity scores include:

• Properly quoted text (which should be there)
• Citations and references (which will always match the sources they cite)
• Standard methodology descriptions that any paper in the field would use in similar language
• Your own previously published work (if your institution has it indexed)

A thesis with extensive case studies, many direct quotations, or a long reference list may show a high similarity score with no actual plagiarism. Review every flagged passage individually.

#Low similarity does not mean you are clear

The converse is also true. If your institution uses a system that checks against a smaller database, it may not flag a match with a source it has not indexed. A 4% similarity score on one system does not guarantee a clean result on the system your institution uses. Running checks on multiple platforms is prudent for high-stakes submissions.

#Step 3: Fix common issues

#Properly attribute quoted text

Any text reproduced verbatim from a source must be enclosed in quotation marks and followed by a citation that includes the page number. If the passage is longer than four lines (the threshold varies by citation style), it should be formatted as a block quote.

#Rewrite overly close paraphrases

If a flagged passage is a close paraphrase, the fix is to rewrite it from scratch after setting the source aside. Do not try to rephrase the paraphrase. Read the original, understand what it says, put it away, and write your own explanation of the same idea.

#Add missing citations

For any flagged passage that represents someone else's idea, method, or finding, add the citation if it is missing. If you cannot find the original source for a passage you wrote, treat it as a direct quote with an unknown source and either find the source or rewrite the passage without it.

#Handle self-citations

For text drawn from your own published papers, follow your institution's guidance. Most universities require a statement at the start of the affected chapter indicating that it is based on or adapted from a named prior publication, with the full citation. Check your institution's specific requirements, as they vary.

#Step 4: Check against your own source papers

Standard plagiarism detection services check your thesis against publicly indexed sources. They may not catch close paraphrases of papers in your personal library that have not been indexed.

Alfred Scholar's plagiarism detection feature checks similarity across the documents in your workspace, which means you can check your thesis chapters against the specific papers you cited. This catches paraphrasing problems that might not appear in a general similarity check because the source paper has not been indexed.

This is particularly useful for:

• Papers published in smaller journals not covered by major databases
• Preprints and working papers you accessed before they were formally published
• Papers in languages where database coverage is weaker

#Step 5: Run a final check

After making revisions based on your initial check, run the full thesis through the checker again before submission. Revisions sometimes introduce new issues, particularly when text is moved, merged, or rewritten. The final check should cover the complete submitted document, not individual chapters.

#Plagiarism checking in Alfred Scholar

Alfred Scholar's plagiarism detection works by comparing documents you upload against each other within your workspace. This makes it practical for checking your thesis against your source papers and your own prior publications.

To use it for pre-submission checking: upload your thesis draft and the key papers you cited, then run the similarity check. The results show which passages in your thesis are similar to which passages in your source documents, with similarity scores at the passage level.

This complements rather than replaces a general detection service. For your final submission check, use both: your institution's preferred system for broad coverage, and Alfred Scholar for targeted cross-checking against your personal document library.

#What your university's checker will look for

Most institutions use Turnitin, iThenticate, or a similar service. These systems check against:

• Published academic papers indexed in their database
• Internet content and websites
• Student paper databases (submissions from other institutions)
• Institutional repositories

The threshold for "acceptable" similarity varies by institution and field. Sciences with standard methodology sections typically have higher baseline similarity than humanities writing. Your supervisor or graduate program office can tell you what threshold applies to your submission.

#Tips for avoiding unintentional plagiarism

1. Take notes in your own words. When reading a source, paraphrase it in your notes immediately rather than copying text. You are less likely to accidentally reproduce copied text that you never realized you wrote down verbatim.
2. Track every source as you go. Add papers to your citation manager when you read them, not later. Sources are hardest to trace after the fact.
3. Use quotation marks consistently in notes. If you copy a passage directly into your notes for any reason, put it in quotation marks and record the page number immediately.
4. For self-plagiarism, plan early. If you know chapters of your thesis will be derived from papers you have published or plan to publish, discuss the attribution requirements with your supervisor at the start of your PhD, not at the end.
5. Run checks chapter by chapter. Do not accumulate problems across the whole thesis before checking.

For guidance on writing the thesis itself, see How to Write a Research Manuscript: A Complete Guide.