To date, we have collected around 740 million from 12 different source since we launched our Event Data service service in 2017. Each event is an online mention of the research associated with a DOI, either via the DOI directly or using the associated URL. However, we know that there is much more out there. Because of this, we would like to explore where we could expand.
We invite proposals to conduct a gap analysis for Event Data sources, looking at what we currently collect and seeing what more could be added.
We are delighted to announce the formation of a new Advisory Group to support us in improving preprint metadata. Preprints have grown in popularity over the last few years, with increasing focus brought by the need to rapidly disseminate knowledge in the midst of a global pandemic. We have supported metadata deposits for preprints under the content type ‘posted content’ since 2016, and members currently register a total of around 17,000 new preprints metadata records each month.
It is time to put the ‘R’ back into R&D.
The Crossref R&D team was originally created to focus on the kinds of research projects that have allowed Crossref to make transformational technology changes, launch innovative new services, and engage with entirely new constituencies. Some Illustrious projects that had their origins in the R&D group include:
DOI Content Negotiation Similarity Check (originally CrossCheck) ORCID (originally Author DOIs) Crossmark The Open Funder Registry The Crossref REST API Linked Clinical Trials Event Data Grant registration ROR And for each project that has graduated, there have been several that have not.
This announcement has been in the works for some time, but everything seems to take longer when there is a pandemic going on, including finding time and headspace to plan out our strategy for the next few years.
Over the last year or so we have had our heads down addressing how to scale our 20-yr-old system and operation – and adapting to new ways of working. But we’ve also spent time talking to people, forging alliances, looking ahead, and making plans.
These connections may consist of citations, or refer to publications which do not always exist as a single content item (its parts may be produced, curated, and published by different organizations and separate activities). Making these connections creates linked data, which is useful because it establishes associations and context.
We have also introduced other interlinking services that address specific types of relationships:
Components allow for the assignment of DOIs to the component parts of a publication (figures, tables, images) which may lead to their reuse.
Crossmark supports the connection of updates which have a material effect on the original work, for example: updates, corrections, and retractions.
Funding data supports identifying the organization that financially supports the research behind a specific publication.
Peer reviews support the host of outputs made publicly available about published scholarly content, for example: referee reports, decision letters, and author responses.
These and other services create relationships between metadata records; however, they share two characteristics that restrict their ability to define relationships:
Both items involved in a relationship must be identified by Crossref DOIs.
The types of relationships are dictated by the mission of the specific service.
The following modifications and new services developed in response to these two limitations:
Allow non-Crossref DOIs to be deposited in an item’s (article/chapter/paper) list of citations.
Support the creation of general typed relationships between items with a Crossref DOI, and other content items with a variety of identifiers.
We maintain an expansive set of relationship types to support the various content items that a research object, like a journal article, might link to. For data and software, we ask you to provide the following information:
identifier of the dataset/software
identifier type: DOI, Accession, PURL, ARK, URI, Other (additional identifier types are also accepted beyond those used for data or software, including ARXIV, ECLI, Handle, ISSN, ISBN, PMID, PMCID, and UUID)
relationship type: isSupplementedBy or references (use the former if it was generated as part of the research results)
description of dataset or software
We and DataCite both use this kind of linking. Data repositories which register their content with DataCite follow the same process and apply the same metadata tags. This means that we achieve direct data interoperability with links in the reverse direction (data and software repositories to journal articles).
The possible relationship types between content items can be as varied as the items themselves. We use a controlled vocabulary to define these relationships, in order to construct an orderly mapped network of content.
This is achieved by (i) an implicit approach where the relation type is a function of a specific service and is declared in the structure of the deposited XML, and (ii) in an explicit approach where the relation type is selected as a value within the deposited metadata.
Reference linking and Cited-by: implicitly creates cites and isCitedBy relationships between a content item and the items in its bibliography
Crossmark: explicit creation of update relations between an item and other items that materially affect it (for example, a retraction)
Funding data: implicit creation of isFundedBy and hasAward relationships between an item and the funding source that supported the underlying research
Linked clinical trials: implicit creation of a belongsTo relationship between and item and a registered clinical trial
Components: implicit creation of a isChildOf relationship between an item and its elemental parts that are assigned their own DOI (limited parent relation typing)
General typed relations: explicitly typed relation between an item with a Crossref DOI and an item with one of several possible identifiers.
Relationship types for associated research objects: intra-work (within a work)
Reciprocal relationship types
Relationship types for associated research objects: inter-work (between works)
Reciprocal relationship types
Related material, such as a protocol
Supplement, such as a dataset generated as part of research results
General typed relations
This service allows for the creation of a typed relationship between an item with a Crossref DOI and another content item. The other item may be represented by another Crossref DOI, a DOI from some other Registration Agency, or an item not identified with a DOI. When DOIs are used, the deposit process will fail if the DOI does not exist. Non-DOI identifiers are not verified.
When DOIs are used, a bidirectional relation is automatically created by us when a relation is created in the deposit of one item in a pair. The DOI with metadata creating the relation is said to be the claimant, the other item does not need to have its metadata directly contain the relationship.
Example: translated article
A single journal article is published in two languages with each being assigned its own DOI. In this example, both are published in the same journal. The original language instance has metadata that contains no indication of the translation instance. The alternative language instance includes in its metadata a relation to the original language instance. Here is a screenshot of the relevant section in the code. Please refer to the code snippet below to see it in context.
<title>Um artigo na língua original, que passa a ser o inglês</title>
<original_language_title language="en">An article in its original language which happens to be English</original_language_title>
<person_name sequence="first" contributor_role="author">
<description>Portuguese translation of an article</description>
<intra_work_relation relationship-type="isTranslationOf" identifier-type="doi">10.5555/original_language</intra_work_relation>
Example: book review
This example has a book review published as an article in the journal The Holocene. The article’s title, taken from the publisher’s site is “Book Review: Understanding the Earth system: compartments, processes and interactions” where this book has the DOI https://doi.org/10.1007/978-3-642-56843-5.
A: The current metadata for the review article gives no indication of the actual book being reviewed: