Similarity Check is a service to help Crossref members actively engage in efforts to prevent scholarly and professional plagiarism. The Similarity Check service is available to eligible Crossref members and is powered by Turnitin’s powerful manuscript checking service, iThenticate.
In order to participate, members need to be including full text URLs specifically for the Similarity Check service within the metadata they deposit with Crossref. This needs to be in place for at least 90% of their content. This is so that Turnitin are able to locate and index each member’s full-text PDF or HTML content, and add it into the Similarity Check content database.
- Why do I need to deposit full text URLs for Similarity Check?
- Whitelisting IP addresses
- How do I deposit full text URLs?
- Confirming your full text URLs
- Need help using iThenticate?
Turnitin (the company that provides the iThenticate service) needs the full text URL for the content associated with each DOI in order to index your content as part of your Similarity Check membership agreement. Even if your a full text URLs are the same as your DOI resource URLs, you still need to enter them separately as specific full text URLs.
Similarity Check members need to ensure their hosting domain has whitelisted Turnitin’s full IP range so that Turnitin’s indexing crawler has access to the member’s full-text content. To do this, members need to contact their hosting provider (if applicable) and ask them to enable Similarity Check indexing for their site by allowing Turnitin’s crawler to access the domain from the following IP ranges:
188.8.131.52 - 184.108.40.206
(with a subnet mask of 220.127.116.11/21)
Please also make sure that robots.txt does not disallow Turnitin’s user agent: UA: TurnitinBot/2.1
For new DOIs:
The full text URL can be included as part of the standard DOI deposit metadata that a member deposits with Crossref. For Similarity Check, the full text URL needs to be deposited within the "crawler-based" collection property, with item crawler "iParadigms". Here's an example:
Remember that the URL must point to the location of the full-text content associated with that DOI, not to the article landing page even if the content is available via a link on that page. The full text URL is most commonly the PDF download link.
You can add full text URLs into your already-deposited DOIs using a resource-only deposit, or by using the Supplemental-Metadata Upload option available from Crossref’s web deposit form.
If you deposit Crossref metadata via API, then please update your existing DOIs by submitting the required XML. Full text URLs can be submitted as part of a metadata deposit (example) or as a resource-only deposit (example). Instructions for uploading resource-only deposits are available here: DOI resource deposits
For existing DOIs (.csv upload)
To update DOIs using the web deposit form, please use the following steps:
- Format your .csv file using the instructions here: Formatting a .csv file for Similarity Check full text URL deposits
- Go to the Web Deposit Form
- Select the "Supplemental-Metadata Upload" option.
- Enter your Crossref username and password in the appropriate fields.
- Enter your email address in the appropriate field.
- Upload your .csv file (from step 1)
- Click "Upload CSV file" and your full text URLs will be submitted to Crossref for processing.
- You will be sent a log via email when your URLs have been processed - please review the log to make sure your DOIs were updated.
Take a look at the Similarity Check page on our website. In the "How to Participate" section you can use our quick checker to see if you've registered Similarity Check urls for more than 90% of your content and are eligible for Similarity Check.
If you aren't at 90% you'll be able to download a CSV showing which of your DOIs don't have these links. They will have NULL in the second column.
As part of your membership to Similarity Check, you will have access to Turnitin's manuscript checking tool iThenticate. If you have questions or need any help using iThenticate, please refer to the iThenticate user manual or the iThenticate API integration guide on Turnitin's help site or contact a member of their Similarity Check support team at firstname.lastname@example.org