This year, metadata development is one of our key priorities and we’re 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; we’ve added a ‘type’ 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, we’re 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. It’s 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 world’s least economically advantaged countries. Eligibility for the program is based on a member’s 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.
Through content negotiation you can request a single metadata record in a specified format. It is a service offered by several DOI registrations agencies (currently Crossref, DataCite, and mEDRA) through the DOI Foundation. It means that you don’t need to know where a DOI is registered in order to retrieve its associated metadata.
How to use content negotiation
Content negotiation is an API request where the format of the metadata returned is specified in the Accept header, for example (using cURL in a terminal):
The formatted citation format uses two additional headers to define the citation style and locale. A full list of citation styles, taken from the CSL repository, is available. Here is an example query:
curl -LH "Accept: text/x-bibliography; style=bibtex; locale=en-US" "https://doi.org/10.1126/science.169.3946.635"
How does it work?
The DOI foundation runs an API that accepts content negotiation requests. It determines which registration agency holds the metadata and redirects the request (which is why -L is included in the examples above, to ensure that redirects are followed).
At Crossref, requests are handled by the transform route of the REST API, so
give the same result. Using 10.23719/1531731, however, will not return a result in the first case because the DOI is registered with DataCite and not Crossref.
Advantages and limitations
Content negotiation is useful if you want to retrieve metadata in a commonly used format, such as BibTeX or RIS. It is also convenient for compiling references in a bibliography in accordance with a publisher style. The other big advantage of content negotiation is that it can retrieve metadata from several DOI registration agencies.
Note that content negotiation maps from multiple schema to multiple schema, which may use different field names and vocabularies and the mapping is not always direct. Sometimes several types are matched to a single field, or differ between registration agencies. For example, the Crossref types book, edited-book, and monograph map to the single RIS type book.
Only one record at a time is returned by content negotiation. For filtering and queries that return multiple metadata records, use the REST API.
