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 journal article content.
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 service agreement. Even if your a full-text URLs are the same as your DOI resource URLs, you still need to enter them separately in your metadata as full-text URLs specifically for the Similarity Check service. This is so that Turnitin are able to locate and index your content, and add it into the Similarity Check content database.
Below, you can find detailed information on how to add these links to your metadata.
- a) Where specifically should these full-text URLs point?
- b) How do I deposit full-text URLs for new DOIs?
- c) How do I deposit full-text URLs for existing DOIs
- d) How can I confirm that you have my full-text URLs?
- e) Whitelisting the Turnitin IP address
- f) Need help using iThenticate?
a) Where specifically should these full-text URLs point?
Option 1: Instructions for members using XML deposit methods
The full-text URL can be included as part of your standard DOI deposit metadata. 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:
Option 2: Instructions for members using one of our Helper Tools
Metadata Manager, the Web Deposit Form and the OJS plugin all contain a specific field where you can add your full-text URL specifically for Similarity Check.
If you've previously registered content without including your full-text URLs for Similarity Check, don't worry - you don't have to do a full re-deposit in order to add them. There are several other options available to you.
Option 1: Use Metadata Manager
If you need to add full-text URLs for just a few items, the easiest way is to use our new Metadata Manager tool. You can find your existing article (even if you didn't originally register it using Metadata Manager) and just fill out the Similarity Check URL field. When you're done, simply save and deposit.
Option 2: Run a "Supplemental-Metadata Upload" the Web Deposit Form
If you have a large number of DOIs to update, you'll definitely find it easier to upload a csv of the DOIs and the missing full-text URLs to our web deposit form using the "Supplemental-Metadata Upload" option. Here's how:
- Format your .csv file using the instructions here: Formatting a .csv file for Similarity Check full text URL deposits. Make sure you save it as a .csv and don't convert it to .xlsx (or any other file type).
- 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.
- If you do get an error, it might be because some spreadsheet programs add additional quotation marks to the column headers. Open your file in a text editor and make sure the top line of the file is still just as below. If there are extra quotation marks, remove them, re-save the file (as .csv) and upload again.
Option 3: Upload a Resource-Only Deposit
If you deposit Crossref metadata by sending us the XML directly, you may wish to update your existing XML using a resource-only deposit (example). Instructions for uploading resource-only deposits are available here: DOI resource deposits.
If you prefer, you can of course just run a standard metadata deposit by adding the Similarity Check URLs (example). Don't forget to update your timestamp!
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. You can then use this CSV to run a "Supplemental-Metadata Upload" using the web deposit form.
Once you've added your Similarity Check URLs to your metadata, the Turnitin indexing crawler will index your content. If your content is protected by authentication, you may need to whitelist their IP address so they can do this.
If this applies to you, please contact your hosting provider 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:
184.108.40.206 - 220.127.116.11
(with a subnet mask of 18.104.22.168/21)
Additionally, please make sure to add 'TurnitinBot' to the robots.txt file.
If your content is openly available, you don't need to do this.
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