What is Similarity Check?

Similarity Check powered by iThenticate is an initiative started by Crossref to help its members actively engage in efforts to prevent scholarly and professional plagiarism. Although there are several plagiarism screening tools already available, they are not well-suited to filtering academic content simply because they haven't had access to the relevant full-text literature to screen against. Similarity Check changes this by creating and continuously growing a database of current and archival scholarly literature.

This database is one of two parts that make up the Similarity Check service. The second part is the iThenticate tool, which compares authored work against the content in the database and highlight matching or similar text for further editorial review.

Log In

Existing Similarity Check members may log into Similarity Check/iThenticate.

Similarity Check in the News

Read articles about Similarity Check and its implementation at member organisations.

Similarity Check/iThenticate Webinars

Introduction to Similarity Check Webinar
The webinar is an informal 30 minute presentation about our innovative originality screening service and how it can add value to your publishing program. Listen to a pre-recorded Introduction to Similarity Check webinar with slides.

Register for a webinar on our webinar page.

Crossref Similarity Check Update Webinar
Date: Tuesday, September 20, 2016
Time: 8:00 am (San Francisco), 11:00 am (New York), 4:00 pm (London)
Moderator: Madeleine Watson

Introduction to Similarity Check in Portuguese
Date: Tuesday, September 1, 2015
Moderator: Rachael Lammey
Webinar Slides
Webinar Recording

Similarity Check Members

View our current Similarity Check Members or download a list of titles included in the Similarity Check database.

How does it work?

To participate in Similarity Check publishers must first allow their content to be indexed and included in the Similarity Check database. All Crossref members are encouraged to contribute to the database regardless of whether they decide to check submissions, as participation will benefit the Similarity Check community and will help prevent other publishers from unknowingly re-publishing your content.

Step two is to begin checking authored works against the database. This is done through the web-based iThenticate system by uploading a document and running a similarity check against the Similarity Check database, and optionally the wider internet. iThenticate returns a set of results listing documents that share a significant degree of textual overlap with the target document.

Finally, we would encourage all participating publishers to display the Similarity Check logo on their websites and in their published documents to show their participation and to help deter would-be plagiarists from copying your content.

Similarity Check Logos

All participating publishers are encouraged to use the Similarity Check logos on their submitted and screened content to show that they are actively checking for plagiarism and to deter would-be plagiarists.  Logos and suggested accompanying text are now available.

How do publishers join Similarity Check?

To join Similarity Check you must first be a Crossref member, and have reviewed the Terms & Conditions of the Similarity Check agreement to ensure you can meet them.  If you are already a CrossRef member you can join by filling in an online application form and signing a license agreement (PDF), and emailing the license agreement to crossref@turnitin.com.  Please keep in mind when reviewing these agreements that they have been carefully vetted by Crossref staff and several member publishers.  Although you have the option of negotiating the terms of the agreement with our technology partner Turnitin, we believe you will find the terms favourable and hope that further negotiations are not necessary.

If you are interested in finding out more about Similarity Check before applying please email crosscheck_info@crossref.org and we will be happy to answer any questions you may have.  You may also find the Frequently Asked Questions further down this page useful.

What does it cost?

Similarity Check fees are in two parts: a per-document checking fee and an annual administrative fee.  Per-document checking fees are paid directly to Turnitin; these fees are significantly less than those charged by Turnitin outside of the Similarity Check initiative, and volume discounts also apply.  The annual administrative fee is paid to Crossref and is set at 20% of your CrossRef annual membership fee.

Frequently Asked Questions (FAQ's)

Please browse through our Frequently Asked Questions section. For a print-friendly summary please see our Similarity Check handout (PDF).

Updated August 24, 2016