Annual Meeting Reports

CrossRef, CrossCheck, CrossMark: An Update

We all use technology to manage the editorial and production processes for our publications. Long gone are the index cards that contained reviewer information, manual checking of references, and those aromatic bluelines. Among the tools used daily in editorial offices are CrossRef’s reference linking service, which revolutionized reference citation; the CrossCheck plagiarism screening service, powered by iThenticate, which allows editors to check easily for similarity between submitted manuscripts and published work; and CrossMark, which is being adopted by many publishers to identify which version of an article is the final published version of record and to notify readers of updates. In this session, CrossRef’s Carol Anne Meyer and Rachel Lammey provided an update on those services.

Meyer started the session with a quiz for the audience. In “So You Think You Know CrossRef”, she challenged attendees to answer a series of questions about CrossRef, including

  • What was the first service CrossRef offered? (DOI linking.)
  • What does DOI stand for? (Digital object identifier.)
  • Which type of organization was not originally eligible to participate in CrossRef? (Secondary publishers.)
  • How many times per month does someone click on or resolve a DOI? (Almost 10 million.)

She also discussed how DOIs should be presented: as URLs. That way, they are not only unique but actionable by both humans and automated systems. Unwieldy DOIs can be shortened at She noted that because of the rapid increase in participating publishers, CrossRef has exhausted all the “10” prefixes with six digits and earlier this year began assigning sevendigit prefixes. Full display guidelines can be found at

According to Meyer, books are the largest growing content type at CrossRef and now account for about 10% of the total DOI links. CrossRef has been assigning DOIs to components—including data sets, figures, tables, and graphics—since 2007, and more than 1 million DOIs now link to data sets in the Protein Data Bank, the International Union of Crystallography, the Organisation for Economic Co-operation and Development, and other organizations.

Lammey continued with an update of CrossCheck and CrossMark. She began by noting that 470 publishers now participate in CrossCheck; more than 34 million content items from 86,000 titles are indexed. More than 50,000 documents are being screened each month, and total documents checked went from about 290,000 in 2011 to about 630,000 in 2012. New features in the iThenticate system, Lammey said, include section exclusion (quarter 2 of 2013), file-size increase (quarter 4 of 2013), increased speed (November 2012), more top-level report information, and an updated document viewer. Development is continuing, and future enhancements will include exclusion of small matches and the ability to report on factors other than the similarity score (for example, the largest source match and largest match based on number of words).

The fundamental principle of CrossMark, Lammey noted, is simple: When content changes, readers need to know, and they need to be able to find out about it in an effective way. Publishers include a CrossMark logo on their content; clicking the logo tells a reader whether there have been any updates, where the publishermaintained version is, and other important information, such as publication history and other publisher-provided data (for example, if a correction or retraction has been issued). If a paper is downloaded from the publisher’s site and then referred to later, a user can simply click the CrossMark logo on the PDF and immediately know whether an article has been updated, something that might otherwise be missed.

CrossMark launched in April 2012, and more than 60,000 deposits and 350 updates have been made since launch. CrossRef is working with more than 20 publishers on CrossMark implementation and integration with FundRef, CrossRef’s new funder-identification service, and other initiatives. Integration with third-party tools is also under way.

In closing, Meyer and Lammey noted that no publisher is an island and that collaboration and connection are key. As a nonprofit organization, CrossRef supports publishers by providing infrastructure to enable enhanced content.