2020 wasn’t all bad. In April of last year, we released our first public data file. Though Crossref metadata is always openly available––and our board recently cemented this by voting to adopt the Principles of Open Scholarly Infrastructure (POSI)––we’ve decided to release an updated file. This will provide a more efficient way to get such a large volume of records. The file (JSON records, 102.6GB) is now available, with thanks once again to Academic Torrents.
Our colleague and friend, Kirsty Meddings, passed away peacefully on 10th December at home with her family, after a sudden and aggressive cancer. She was a huge part of Crossref, our culture, and our lives for the last twelve years.
Kirsty Meddings is a name that almost everyone in scholarly publishing knows; she was part of a generation of Oxford women in publishing technology who have progressed through the industry, adapted to its changes, spotted new opportunities, and supported each other throughout.
Crossref has supported depositing metadata for preprints since 2016 and peer reviews since 2018. Now we are putting the two together, in fact we will permit peer reviews to be registered for any content type.
2020 has been a very challenging year, and we can all agree that everyone needs a break. Crossref will be providing very limited technical and membership support from 21st December to 3rd January to allow our staff to rest and recharge. We’ll be back on January 4th raring to answer your questions. Amanda explains more about why we made this decision.
A DOI (digital object identifier) is a persistent identifier attached to content (such as an article, chapter). It’s displayed as a link, and looks like this:
As you can see, it has several parts:
https://0-doi-org.brum.beds.ac.uk/ = the DOI resolver: makes the DOI a URL (actionable)
10.5555 = prefix: assigned by Crossref
YFRU1371 = suffix: decided and assigned by the member, should be opaque.
The prefix and suffix make a DOI, and with the DOI resolver form a DOI link.
As we mention above, the suffix should be opaque. An opaque identifier does not encode or describe any information about the work, such as publication name, date, or ISSN. It’s important to avoid encoding any human-readable information, so if any of the metadata associated with the DOI changes, there is no confusion between the information encoded in the DOI and that found in its metadata.
For example, 10.5555/njevzkkwu4i7g is opaque, but 10.5555/ogs.2016.59.1.1 encodes information which may change and therefore could be confusing or misleading in future.
The DOI link uses the DOI resolver to look up the registered URL for the item. This shows why it’s important to keep the metadata up-to-date, so that the DOI points to the correct URL for the item.
DOIs at different levels
A DOI may refer to a journal or book (a title-level DOI), or to a specific article or chapter.
Journals and DOIs
Like a set of nesting dolls, a journal may be made up of volumes, each containing a number of issues, each containing a number of articles. You can assign a DOI at each level, for example:
journal-level-DOI (sometimes called the title-level-DOI) 10.5555/QYPF2031. Like an ISSN, it refers to the whole journal
The role of the journal-level-DOI, volume-level-DOI, and issue-level-DOI is to link persistently to a point in the journal structure. These DOIs do not have any associated content, and it does not cost anything to register these DOIs.
However, article-level-DOIs do have associated content, and therefore a fee applies to register these DOIs.
Books and DOIs
Like a set of nesting dolls, a book may be made up of chapters. Again, you can assign a DOI at each level, for example:
book-level-DOI (sometimes called the title-level-DOI) 10.5555/ZAAR1365. Just like an ISBN, it refers to the whole book.
Both book-level-DOIs and chapter-level-DOIs have associated content, and therefore a fee applies to register these DOIs.