This year, metadata development is one of our key priorities and weâre making a start with the release of version 5.4.0 of our input schema with some long-awaited changes. This is the first in what will be a series of metadata schema updates.
What is in this update?
Publication typing for citations
This is fairly simple; weâve added a âtypeâ attribute to the citations members supply. This means you can identify a journal article citation as a journal article, but more importantly, you can identify a dataset, software, blog post, or other citation that may not have an identifier assigned to it. This makes it easier for the many thousands of metadata users to connect these citations to identifiers. We know many publishers, particularly journal publishers, do collect this information already and will consider making this change to deposit citation types with their records.
Every year we release metadata for the full corpus of records registered with us, which can be downloaded for free in a single compressed file. This is one way in which we fulfil our mission to make metadata freely and widely available. By including the metadata of over 165 million research outputs from over 20,000 members worldwide and making them available in a standard format, we streamline access to metadata about scholarly objects such as journal articles, books, conference papers, preprints, research grants, standards, datasets, reports, blogs, and more.
Today, weâre delighted to let you know that Crossref members can now use ROR IDs to identify funders in any place where you currently use Funder IDs in your metadata. Funder IDs remain available, but this change allows publishers, service providers, and funders to streamline workflows and introduce efficiencies by using a single open identifier for both researcher affiliations and funding organizations.
As you probably know, the Research Organization Registry (ROR) is a global, community-led, carefully curated registry of open persistent identifiers for research organisations, including funding organisations. Itâs a joint initiative led by the California Digital Library, Datacite and Crossref launched in 2019 that fulfills the long-standing need for an open organisation identifier.
We began our Global Equitable Membership (GEM) Program to provide greater membership equitability and accessibility to organizations in the worldâs least economically advantaged countries. Eligibility for the program is based on a memberâs country; our list of countries is predominantly based on the International Development Association (IDA). Eligible members pay no membership or content registration fees. The list undergoes periodic reviews, as countries may be added or removed over time as economic situations change.
We regularly see developers using regular expressions to validate or scrape for DOIs. For modern Crossref DOIs the regular expression is short
/^10.\d{4,9}/[-._;()/:A-Z0-9]+$/i
For the 74.9M DOIs we have seen this matches 74.4M of them. If you need to use only one pattern then use this one.
The other 500K are mostly from Crossrefâs early days when the battle between âhuman-readableâ identifiers and âopaqueâ identifiers was still being fought, the web was still new, and it was expected that âdoiâ would become as well a supported URI schema name as âgopherâ, âwaisâ, âŚ. Ok, that didnât go so well.
An early Crossrefâs member was John Wiley & Sons. They faced the need to design DOIs without much prior work to lean on. Many of those early DOIs are not expression friendly. Nevertheless, they are still valid and valuable permanent links to the workâs version of record. You can catch 300K more DOIs with
/^10.1002/[^\s]+$/i
While the DOI caught is likely to be the DOI within the text it may also contain trailing characters that, due to the lack of a space, are caught up with the DOI. Even the recommended expression catches DOIs ending with periods, colons, semicolons, hyphens, and underscores. Most DOIs found in the wild are presented within some visual design program. While pleasant to look at the visual design can misdirect machines. Is the period at the end of the line part of the DOI or part of the design? Is that endash actually a hyphen? These issues lead to a DOI bycatch.
Adding the following 3 expressions with the previous 2 leaves only 72K DOIs uncaught. To catch these 72K would require a dozen or more additional patterns. Each additional pattern, unfortunately, weakens the overall precision of the catch. More bycatch.
Crossref is not the only DOI Registration Agency and while our members account for 65-75% of all registered DOIs this means there are tens of millions of DOIs that we have not seen. Luckily, the newer RAs and their publishers can copy our successes and avoid our mistakes.
