Similarity Check guide

So, you’ve signed up for Similarity Check but need a little bit of help to get started? Well, you’ve come to just the right place. And if you can’t find the answers you need in the information below, we’re always here to help so please get in touch with our support team.

How to join

  1. Are you a member of Crossref? If yes, then please proceed! If you’re not one of our members though, don’t be deterred as you can always take out your own subscription to iThenticate by contacting Turnitin.

  2. Check that you are depositing article-level DOIs with us which include the full-text URL within the <iparadigms> field. Here’s an example of how to include this field in your DOI XML.

If you use our web form to deposit DOIs, make sure to select the ‘Add Similarity Check URL’ button and insert the URL for the full-text PDF, HTML or plain text content into the field provided.

You need to have full-text URLs in at least 90% of your journal content DOIs on application to join Similarity Check. Full technical instructions for how to add these links into your existing DOI metadata can be found on our help site.

  1. If your full-text content is subscription-based, please ask your hosting provider to whitelist Turnitin’s full IP range.

  2. Review the Terms & Conditions on our Similarity Check service page.

  3. Review Turnitin’s Service Agreement and email a signed copy to

  4. Complete the online application form.

Together, Crossref and Turnitin will then review your documentation, co-sign your service agreement, and test your metadata to ensure full-text links are correctly included. As soon as this process is complete, Turnitin will send your nominated iThenticate admin user an account activation email. If you’re waiting for your activation email, please do keep an eye on your spam folder as sometimes emails from Turnitin can get caught in those filters.

Using iThenticate

If you are already a Similarity Check member, you can login to your iThenticate account.

For help using iThenticate, please refer to Turnitin’s Similarity Check User Manual or get in touch with Turnitin’s support team at

Please contact our member services team with any questions or to get set up, or contact our support team for any technical or troubleshooting questions.

Last Updated: 2018 January 2 by Madeleine Watson