iThenticate is a web-based similarity-checking service used by researchers worldwide to review written work before submission or publication. Maastricht University (UM) Library provides access to iThenticate for UM-affiliated researchers as part of its commitment to responsible publishing and academic integrity.
The tool compares your document against a large corpus of published journal articles, books, preprints, websites, and other indexed sources. The resulting Similarity Report highlights where text in your document matches content in that corpus. In the current version — iThenticate 2 — the service also includes an AI Writing Detection indicator, which can help flag text that may have been generated by AI tools such as ChatGPT.
Check a manuscript or PhD thesis
This tool is for research purposes only!
For educational purposes, use Turnitin Originality (available through the Canvas digital learning environment).
Understanding your results
A similarity score or an AI writing indicator is a starting point for review, not a verdict. Results should always be interpreted by the author in the context of the specific document and disciplinary norms.
Similarity check
The similarity score expresses the percentage of your document that matches text found in iThenticate’s indexed sources. This figure alone does not indicate plagiarism or other integrity concerns. Common reasons for legitimate matches include:
- Direct quotations with proper attribution
- Standard phrasing in methods, ethics statements, or acknowledgements
- Shared reference lists or bibliographies
- Previously published work by the same author (self-citation)
Your task when reviewing the report is to examine each highlighted match and decide whether it is appropriately attributed, contextually expected, or requires revision. Disciplinary norms vary considerably; what counts as a “normal” similarity range differs between a review article, an empirical paper, and a doctoral thesis.
AI writing detection
Where AI Writing Detection is enabled in UM’s iThenticate configuration, the report will include a separate AI Writing percentage. This figure reflects the proportion of text the system identifies as potentially AI-generated. It is calculated independently from the similarity score and has its own dedicated view within the report.
Keep the following in mind when interpreting AI writing results:
- The AI writing percentage is separate from and not comparable to the similarity score
- A result is only generated when the submission meets eligibility requirements: supported language (currently including English and Spanish), supported file type, and a document length between approximately 300 and 30,000 words of prose
- Lower AI percentages may be suppressed in the report to reduce the risk of false positives
- AI detection cannot prove that AI tools were used — it indicates a statistical pattern that merits closer reading
- Use the AI Writing indicator as an invitation to review the relevant passages, not as a conclusion.
Support & Contact
iThenticate provides a scale of up-to-date manuals and instructions on their own website.
Please be aware that information in these manuals and videos about logging in and account settings are not applicable to UM users of this service.
If you encounter login problems, cannot access your account, or have questions about which service to use, contact Maastricht University Library directly.
