DataCite on Crossref

Metadata for research integrity: a joint guide from Crossref and DataCite

Helena Cousijn — Wed, 01 Apr 2026 00:00:00 +0000

Why metadata matters for research integrity and jow to contribute

Some aspects of research integrity depend on accurate, complete, and connected metadata. This joint guide from Crossref and DataCite sets out the metadata elements most critical for assessing research integrity—and how all stakeholders can contribute to and benefit from a richer, more trustworthy scholarly record.

Strategists

Understand why metadata is infrastructure for research integrity. Why completeness, accuracy, and openness across the scholarly record matters for systemic trust in research.

Decision-makers

Know which metadata elements to require, check, and act on. A practical resource for publishers, funders, and institutions making metadata-related policy decisions.

Practitioners

Learn how to deposit, enrich, and query research integrity metadata. Step-by-step guidance using Crossref and DataCite services and open APIs.

What this guide covers

This guide walks through the key metadata elements that enable research integrity assessment, and explains how to contribute them via Crossref and DataCite:

Contributors and their roles—identifying who did what
Affiliations—linking researchers to institutions
Dates—submission, acceptance, publication, and update dates
Funder, funding, and grant information—transparency on who paid for the research
Versioning—tracking how a work has changed over time
Retractions, corrections, and updates—keeping the record accurate
Abstracts and descriptions—what the work is actually about
Clinical trials—registration and reporting
References—connecting works to what they cite
Peer reviews—when and how work was reviewed
Publisher and steward—accountability for the record
Record and resource types—what kind of object is this?
Relationships and related identifiers—linking datasets, preprints, articles, and more
Rights, licences, and access—how the work can be used

The guide also sets out a call to action for each stakeholder group: how to enrich your records, query existing metadata via APIs, and report inconsistencies.

Read the full guide

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Strengthening support for data citations and saying goodbye to Event Data

Martyn Rittman — Tue, 24 Mar 2026 00:00:00 +0000

We’re excited to announce a new data citation API endpoint and are seeking your feedback. The new service makes existing data citation relationships in our metadata available, thereby surfacing this part of the research nexus. At the same time, we’ve decided that it’s time to move on from Event Data.

Time to say goodbye

Metadata about published scholarly research has evolved, and continues to evolve in exciting ways. A published article, book, or conference paper is only a single piece of the puzzle. A host of digital identifiers and items can be put together to form a more complete picture of a research project. This is what forms the basis of the research nexus—a rich and reusable open network of relationships connecting research organisations, people, things, and actions; a scholarly record that the global community can build on forever, for the benefit of society.

Ten years ago, we launched Event Data to surface mentions of research around the Internet. What were people saying about published research? Could this discourse contribute to post-publication review and validation? We set up Event Data to capture use of Crossref DOIs in the online world from a variety of sources, including blog posts, social media, websites, and annotations. The idea was that diverse mentions (or “events”) could supplement traditional citation counts as a way to capture the value of research.

Today, the focus is increasingly on transparency, research integrity, and the completeness of outputs. Trust in research is shaped by knowing who the funder was, being able to reanalyse the original data, or checking for bugs in the analysis code. There are also more identifiers for objects within the research space and they are used more widely. This shift is evident in the relatively low usage of Event Data. We can no longer justify the resources and cost that goes into maintaining it as a service. Instead, we will focus on enabling and surfacing relationships between different types of research outputs, starting with links to datasets.

For these reasons, we have decided to sunset the Event Data API and from 23 April 2026 it will no longer be available (although historical data will still be available). In its place, we’re making available an API endpoint for data citations.

Visibility for data citations

The new API endpoint focuses solely on data citations and uses references and relationships deposited by Crossref members, including Crossref articles referencing datasets with either Crossref or DataCite DOIs. While our metadata contains many data citations, and some of them are labelled as data citations, it is often difficult to find them because they are swamped in number by other citations. If you are trying to get data citations directly from our REST API, it’s like looking for a needle in a haystack. This new endpoint makes connections easier to find, enabling organisations to track when research is reused, cited, and built upon. By putting this metadata into a dedicated service, we are making it easier for interested organisations to track and find data citations. Our goal is to make existing sets of connections easier to access, giving clarity to how scholarly works link to the data that supports them.

This beta version will allow us the opportunity to incorporate feedback from the community and make changes to improve delivery. We received early positive feedback from a number of interested organisations. Later this year we will assess whether it is ready for production, needs more work, or if insufficient interest from the community suggests we should pursue a different solution.

Anyone interested in data citations is invited to try the new endpoint. Please let us know your feedback via the community forum. You can find supporting documentation on our website and Swagger documentation, including the opportunity to try out features.

Edited 15 June 2026: link to historical Event Data added.

Joint statement on research data

Hylke Koers — Tue, 28 Nov 2023 00:00:00 +0000

STM, DataCite, and Crossref are pleased to announce an updated joint statement on research data.

In 2012, DataCite and STM drafted an initial joint statement on the linkability and citability of research data. With nearly 10 million data citations tracked, thousands of repositories adopting data citation best practices, thousands of journals adopting data policies, data availability statements and establishing persistent links between articles and datasets, and the introduction of data policies by an increasing number of funders, there has been significant progress since. It now seems appropriate to focus on providing updated recommendations for the various stakeholders involved in research data sharing.

The premise of the original joint statement still stands: most stakeholders across the spectrum of researchers, funders, librarians and publishers agree about the benefits of making research data available and findable for reuse by others. This improves utility and rigor of the scholarly record. Still, research data sharing is not yet a self-evident step in the research lifecycle. We now have sufficient scholarly communication infrastructure in place to bring about widespread change and believe momentum is building for collective action.

It is in this context that DataCite, a global membership community working with over 2800 repositories around the world, and STM, whose membership consists of over 140 scientific, technical, and medical publishing organisations, are issuing this joint statement. Crossref, a nonprofit open infrastructure with over 18,000 institutional members from 150 countries, joins this call, recognising the need for an amplified focus on data citation. The aim of this statement is to accelerate adoption of best practices and policies, and encourage further development of critical policies in collaboration with a wide group of stakeholders.

Signatories of this statement recommend the following as best practice in research data sharing:

When publishing their results, researchers deposit related research data and outputs in a trustworthy data repository that assigns persistent identifiers (DOIs where available). Researchers link to research data using persistent identifiers.
When using research data created by others, researchers provide attribution by citing the datasets in the reference section using persistent identifiers.
Data repositories enable sharing of research outputs in a FAIR way, including support for metadata quality and completeness.
Publishers set appropriate journal data policies, describing the way in which data is to be shared alongside the published article.
Publishers set instructions for authors to include Data Citations with persistent identifiers in the references section of articles.
Publishers include Data Citations and links to data in Data Availability Statements with persistent identifiers (DOIs where available) in the article metadata registered with Crossref.
In addition to Data Citations, Data Availability Statements (human- and machine-readable) are included in published articles where appropriate.
Repositories and publishers connect articles and datasets through persistent identifier connections in the metadata and reference lists.
Funders and research organisations provide researchers with guidance on open science practices, track compliance with open science policies where possible, and promote and incentivize researchers to openly share, cite and link research data.
Funders, policymaking institutions, publishers and research organisations collaborate towards aligning FAIR research data policies and guidelines.
All stakeholders collaborate in the development of tools, processes, and incentives throughout the research cycle to enable sharing of high-quality research data, making all steps in the process clear, easy and efficient for researchers by providing support and guidance.
Stakeholders responsible for research assessment take into account data sharing and data citation in their reward and recognition system structures.

We, the following signatories shall adopt and promote the relevant best practices laid out above. We hope that our action inspires the community, including researchers, research funders, research institutions, data repositories and publishers, to join us in making it easy for researchers to share, link and cite research data.

Endorse the statement here.

Data Citation: what and how for publishers

Rachael Lammey — Fri, 23 Nov 2018 00:00:00 +0000

We’ve mentioned why data citation is important to the research community. Now it’s time to roll up our sleeves and get into the ‘how’. This part is important, as citing data in a standard way helps those citations be recognised, tracked, and used in a host of different services.

This week A Data Citation Roadmap for Scientific Publishers was published in Scientific Data. This roadmap is the outcome of a collaboration between different publishers that worked on identifying all steps you need to take as a publisher to implement data citation. If you want to know more about establishing a data policy, capturing data citations at the point of submission, or tagging data citations in your XML, we recommend you take a look at this article!

In this blog post, we’ll discuss the steps you need to take after you’ve implemented this roadmap. The steps in the roadmap describe how you can track & tag data citation yourself. Here we describe how Crossref can help you make these available to the rest of the community.

The ‘what’

Here’s the recap! From the Crossref perspective, there are two ways to add data citation links into the metadata that you register:

1. Metadata deposits using the references section of the schema

This is where ‘citations’ are normally recorded. Publishers include the data citation into the deposit of bibliographic references for each publication.

Publishers can deposit the full data or software citation as a unstructured reference. For guidance here, we recommend that authors cite the dataset or software based on community best practice (Joint Declaration of Data Citation Principles, FORCE11 citation placement, FORCE11 Software Citation Principles).

<citation key="ref=3">
<unstructured_citation>Morinha F, Dávila JA, Estela B, Cabral JA, Frías Ó, González JL, Travassos P, Carvalho D, Milá B, Blanco G (2017) Data from: Extreme genetic structure in a social bird species despite high dispersal capacity. Dryad Digital Repository. http://dx.doi.org/10.5061/dryad.684v0</unstructured_citation\>
</citation>
</citation_list>

Or they can employ any number of reference tags currently accepted by Crossref.

<citation key="ref2">
<doi>10.5061/dryad.684v0</doi>
<cYear>2017</cYear>
<author>Morinha F, Dávila JA, Estela B, Cabral JA, Frías Ó, González JL, Travassos P, Carvalho D, Milá B, Blanco G</author>
</citation>

We are exploring JATS4R recommendations to expand the current collection and better support these citations - more on this soon. We also encourage additional suggestions from the community.

2. Metadata deposits using the relations section of the schema

This is where other relationships can be recorded. Publishers assert the data link in the relationship section of the metadata deposit. Here, publishers can identify data which are direct outputs of the research results if this is known. This level of specificity is optional, but we’d recommend it as it can support scientific validation and research funding management.

Data and software citations via relation type enables precise tagging of the dataset and its specific relationship to the research results published. To tag the data & software citation in the metadata deposit, we ask for the description of the dataset & software (optional), dataset & software identifier and identifier type (DOI, PMID, PMCID, PURL, ARK, Handle, UUID, ECLI, and URI), and relationship type.

<program xmlns="http://www.crossref.org/relations.xsd">
<related_item>
<description>Data from: Extreme genetic structure in a social bird species despite high dispersal capacity</description>
<inter_work_relation relationship-type="references" identifier-type="doi">10.5061/dryad.684v0</inter_work_relation>
</related_item>
</program>
</doi_relations>

In general, use the relation type references for data and software resources.

Publishers who wish to specify that the data or software resource was generated as part of the research results can use the isSupplementedBy relation type.

The ‘how’

I create my own XML and register it with Crossref

Add links to datasets into your reference lists, including their DOIs if available as shown above and deposit them with Crossref. We’ll do the rest. If you want to add references to existing metadata records, you don’t need to redeposit the full article metadata, you can send us a resource-only deposit that just contains the reference metadata to append that to the existing metadata for the article. You can also use this method if you prefer to deposit references in a separate workflow to registering your content (we know some members prefer to work this way).

I’ve started using Metadata Manager for journal article deposits

Article<->Data relationships in Crossref

You can deposit data citations using either method using our new Metadata Manager tool. When entering journal article metadata, you can use the ‘Related Items’ section to enter the DOI (or other identifier) for the dataset, the type of identifier, a description of the relation type e.g. ‘Data from: Extreme genetic structure in a social bird species despite high dispersal capacity’, and the relation type - ‘references’ or ‘is supplemented by’ depending on the relationship between the data and the article as described above. When you make the deposit, this relationship information will be registered in Crossref along with the rest of the article metadata.

Metadata Manager also has a section where you can enter and match your references, and then deposit these with Crossref. If you choose this method, enter any data citations into the references section before depositing the article metadata with Crossref.

If you want to add this information to deposits you have already made using Metadata Manager, you can search for the journals and articles in the interface, bring up the existing metadata and add in the additional information before redepositing.

I use “simple text query” to search for and deposit references

Make sure you include any citations to data in the references you add into Simple Text Query. When you use simple text query to deposit these references, they will then be added into the article metadata in the Crossref database.

If you use OJS, they’re working on functionality (due for release soon) that will make it easier to deposit reference metadata with Crossref, so you can include citations to data in that.

All of this metadata—registered with Crossref—make it possible to build up pictures of data citations, linking, and relationships. Whether the citations come from the authors in the reference list or they are extracted by the publisher and then deposited, Crossref collects them across publishers. We then make the aggregate set freely available via Crossref’s APIs in multiple interfaces (REST, OAI-PMH, OpenURL) and formats (XML and JSON). DataCite does the same for data repositories and so this provides an easy way for publishers and data repositories to exchange information about data citations. As mentioned previously, this all feeds in Event Data. Data is made openly available to a wide host of parties across the extended research ecosystem including funders, research organisations, technology and service providers, indexers, research data frameworks such as Scholix, etc.

Do you have questions about how to add these links to your Crossref or DataCite metadata? We’ll be running a series of webinars in early 2019 to give you a chance to join us live and ask any questions you have. Eager to get started in the meantime? Let us know and we’ll start to coordinate.

Why Data Citation matters to publishers and data repositories

Helena Cousijn — Thu, 08 Nov 2018 00:00:00 +0000

A couple of weeks ago we shared with you that data citation is here, and that you can start doing data citation today. But why would you want to? There are always so many priorities, why should this be at the top of the list?

I’m sure you heard this before—data sharing and data citation are important for scientific progress. The three key reasons for this are:

1) Transparency and reproducibility

Most scientific results that are shared today are just a summary of what researchers did and found. The underlying data are not available, making it difficult to verify and replicate results. If data would always be made available with publications, transparency of research would be greatly improved.

2) Reuse

The availability of raw data allows other researchers to reuse the data. Not just for replication purposes, but to answer new research questions.

3) Credit

When researchers cite the data they used, this forms the basis for a data credit system. Right now researchers are not really incentivized to share their data, because nobody is looking at data metrics and measuring their impact. Data citation is a first step towards changing that.

The benefits described above are all quite long-term, so why, as a publisher or data repository, should you put your resources towards implementing data citation workflows now? During our pre-conference workshop at FORCE2018 we asked repositories and publishers this question. Below you’ll find some of the answers.

Data repositories

For data repositories, data citation leads to increased visibility of both the repository and the datasets. The workshop revealed that many repositories do a lot of work to establish links between articles and datasets, thereby significantly contributing to transparency in research. Some of the repositories explained that they hire curators that text mine articles to find associations and manually curate datasets to ensure information about links is part of the metadata. This is reflected in Event Data, where 99% of links between articles and datasets comes from data repository metadata. This downstream enrichment of metadata is useful, but it would be more effective if all stakeholders strive to establish these links at a much earlier stage in the research communication process.

ICPSR, the Inter-university Consortium for Political and Social Research, shared:

ICPSR views data citation as vital. As a large social science data archive, ICPSR curates, preserves, and distributes data for the research community to re-use over time. Data citation makes data visible to the research community. Without it, data cannot be accessed for re-use or reproduced for transparency. Its use cannot be tracked and counted to reveal its impact and potential for new uses by investigators in new fields or in combination with new types of data. Data creators cannot receive adequate credit for their intellectual output. And the original investment by funders and scientists to create those data stops producing dividends. Therefore, data citation plays an essential role in the data sharing lifecycle.

Proper data citation, with a unique identifier, makes it much easier to measure impact. When data use is not cited or cited obliquely, it is rendered virtually invisible. Hence, much data use is still not easily detected. The ICPSR Bibliography of Data-related Literature represents ICPSR’s efforts to identify publications that analyze data distributed at ICPSR and link them directly to the data in the ICPSR catalog. As of 2018, ICPSR has a searchable database that contains nearly 80,000 citations of published and unpublished works resulting from analyses of data held in the archive. ICPSR also makes the case for data citation in its brief new video, “ICPSR 101: Why Should I Cite Data?”

GBIF, the Global Biodiversity Information Facility, explained:

The work required to collect, clean, compile and publish biodiversity datasets is significant and deserves recognition. Researchers publish studies based on data made available through GBIF.org at a rate of about 2 papers every single day. It is crucial for GBIF to link these scientific uses to the underlying data as one measure of demonstrating the value and impact of sharing free and open biodiversity data. At the moment, however, only about 10 percent of authors cite or acknowledge the datasets used in research papers properly. As a result, data publishers efforts often risk going unnoticed, and the true impact of sharing data remains invisible. GBIF will continue to work with publishers and researchers to provide guidance and input for how to best cite the use of GBIF-mediated data in scientific journals to ensure proper attribution and reproducible research and to demonstrate the true value of free and open access to biodiversity data.

Publishers

By ensuring data is cited in a consistent way, publishers help provide transparency and context for the content they publish. Depositing that information as part of the Crossref metadata helps that work go further by uncovering how data is being used across multiple publications and publishers This means patterns can be explored and researchers can gain more comprehensive recognition and credit for the work they have done.

Melissa Harrison, Head of Production Operations at eLife says:

eLife is committed to ensuring researchers get credit for all their outputs, and data is a major component of this. We’re working with Crossref and JATS4R to enable publishers to tag their JATS data content consistently and thus create an easy crosswalk to their Crossref deposits. The JATS4R guidance on Data Availability Statements, linked to and incorporating data citations, will be updated soon, please watch that space!

It will be really interesting to see how much re-use of previously published data is happening, look for patterns in re-use, and see links and hopefully building up of data by different research groups. Ultimately, this will incentivize researchers and publishers to ensure it is correctly accredited at source and in publications, improving the cycle further.’

Anita de Waard, VP of Research Collaborations at Elsevier, says:

One of the key recommendations of the Force11 Manifesto was to “3.3 Add data, software, and workflows into the publication as first-class research objects”, which will allow greater reproducibility and rigor to experimental research, and allow the reuse of all digital artefacts in the scholarly lifecycle. By following the data citation principles, we achieve two things: the author presents a richer representation of their work, and the data producer receives credit for the hard work of curating and publishing citable datasets.

Mendeley Data and Elsevier are active contributors to the Scholix framework that as a collaborative and open standard, allows the open mining of relationships between articles and datasets. We are also active participants in the new Enabling FAIR Data Project, and next to supporting the TOP Guidelines in all domains, require all authors in the earth and space sciences to deposit their data before publication.

Next week at Crossref LIVE18, Patricia Cruse from DataCite will talk about Data Citations and why they matter. If you’re in Toronto next week, do not hesitate to ask her or anyone from Crossref anything you want to know about data citation!

Data citation: let’s do this

Rachael Lammey — Thu, 04 Oct 2018 00:00:00 +0000

Data citation is seen as one of the most important ways to establish data as a first-class scientific output. At Crossref and DataCite we are seeing growth in journal articles and other record types citing data, and datasets making the link the other way. Our organisations are committed to working together to help realize the data citation community’s ambition, so we’re embarking on a dedicated effort to get things moving.

Efforts regarding data citation are not a new thing. One of the first large-scale initiatives to establish data citation as a standard academic practice was the FORCE11 Joint Declaration of Data Citation Principles (JDDCP) in 2014. This declaration was endorsed by over 100 organisations in the scholarly community as well as many individuals.

Following this agreement on how data citation should be done, many projects followed. Within FORCE11, the Data Citation Implementation Pilot brought together publishers and repositories to put data citation into practice and work on the implementation of the JDDCP. Within the context of the Research Data Alliance, a data-literature linking group started under the name of Scholix to establish a framework for exchanging information about the relationships between articles and datasets. The infrastructure building blocks now feed into projects such as Make Data Count and Enabling FAIR Data.

Projects aside, if datasets are cited consistently and in a standard way, it will make it much easier for the research community to see links between different research outputs and work with these outputs. It also makes it much easier to count these citations, so that researchers can get credit for their data and the sharing of that data.

The underlying work has been done to create an infrastructure that will effectively support and disseminate information on data citation. Data citation is here today!

Different organisations know how to handle data citations, and are starting to count these and make that information available in turn. This means that the only thing that’s needed is for people to actually cite data, and this information be captured and passed on. Some Crossref and DataCite members have already made great progress on this already (see Melissa Harrison’s blog on what eLife is doing).

The goals of all the data citation projects can only be realized if you start doing data citation, and we know you’ll have questions about it…

In the coming months, we’ll be posting several blogs and organizing sessions to tell you how you can start doing data citation - if you’re attending FORCE2018 you can catch our joint workshop there. So stay tuned and please get in touch if you can’t wait, we’d love to help you get started!

Org ID: a recap and a hint of things to come

John Chodacki — Thu, 02 Aug 2018 00:00:00 +0000

Cross-posted on the blogs of University of California (UC3), ORCID, and DataCite: https://doi.org/10.5438/67sj-4y05.

Over the past couple of years, a group of organisations with a shared purpose—California Digital Library, Crossref, DataCite, and ORCID—invested our time and energy into launching the Org ID initiative, with the goal of defining requirements for an open, community-led organisation identifier registry. The goal of our initiative has been to offer a transparent, accessible process that builds a better system for all of our communities. As the working group chair, I wanted to provide an update on this initiative and let you know where our efforts are headed.

Community-led effort

First, I would like to summarize all of the work that has gone into this project, a truly community-driven initiative, over the last two years:

A series of collaborative workshops were held at the Coalition for Networked Information (CNI) meeting in San Antonio TX (2016), the FORCE11 conference in Portland OR (2016), and at PIDapalooza in Reykjavik (2016).
Findings from these workshops were summarized in three documents, which we made openly available to the community for public comment:
organisation Identifier Project: A Way Forward (PDF)
organisation Identifier Provider Landscape (PDF)
Technical Considerations for an organisation Identifier Registry (PDF)
A Working Group worked throughout 2017 and voted to approve a set of recommendations and principles for ‘governance’ and ‘product’:
Governance Recommendations
Product Principles and Recommendations
We then put out a Request for Information that sought expressions of interest from organisations to be involved in implementing and running an organisation identifier registry.
There was a really good response to the RFI; reviewing the responses and thinking about next steps led to our most recent stakeholder meeting in Girona in January 2018, where ORCID, DataCite, and Crossref were tasked with drafting a proposal that meets the Working Group’s requirements for a community-led, organisational identifier registry.

Thank you

I want to take this opportunity to thank everyone who has contributed to this effort so far. We’ve been able to make good progress with the initiative because of the time and expertise many of you have volunteered. We have truly benefited from the support of the community, with representatives from Alfred P. Sloan Foundation; American Physical Society, California Digital Library, Cornell University, Crossref, DataCite, Digital Science, Editeur, Elsevier, Foundation for Earth Sciences, Hindawi, Jisc, ORCID, Ringgold, Springer Nature, The IP Registry, and U.S. Geological Survey involved throughout this initiative. And we couldn’t have done any of it without the help and guidance of our consultants, Helen Szigeti and Kristen Ratan.

The way forward

The recommendations from our initiative have been converted into a concrete plan for building a registry for research organisations. This plan will be posted in the coming weeks.

The initiative’s leadership group has already secured start-up resourcing and is getting ready to announce the launch plan—more details coming soon.

We hope that all stakeholders will continue to support the next phase of our work – look for announcements in the coming weeks about how to get involved.

As always, we welcome your feedback and involvement as this effort continues. Please contact me directly with any questions or comments at john.chodacki@ucop.edu. And thanks again for your help bringing an open organisation identifier registry to fruition!

References

Bilder, G., Brown, J., & Demeranville, T. (2016). Organisation identifiers: current provider survey. ORCID. https://doi.org/10.5438/4716

Cruse, P., Haak, L., & Pentz, E. (2016). organisation Identifier Project: A Way Forward. ORCID. https://doi.org/10.5438/2906

Fenner, M., Paglione, L., Demeranville, T., & Bilder, G. (2016). Technical Considerations for an organisation Identifier Registry. https://doi.org/10.5438/7885

Laurel, H., Bilder, G., Brown, C., Cruse, P., Devenport, T., Fenner, M., … Smith, A. (2017). ORG ID WG Product Principles and Recommendations. https://doi.org/10.23640/07243.5402047

Laurel, H., Pentz, E., Cruse, P., & Chodacki, J. (2017). organisation Identifier Project: Request for Information. https://doi.org/10.23640/07243.5458162

Pentz, E., Cruse, P., Laurel, H., & Warner, S. (2017). ORG ID WG Governance Principles and Recommendations. https://doi.org/10.23640/07243.5402002

PIDs for conferences - your comments are welcome!

Aliaksandr Birukou — Thu, 19 Apr 2018 00:00:00 +0000

Aliaksandr Birukou is the Executive Editor for Computer Science at Springer Nature and is chair of the Group that has been working to establish a persistent identifier system and registry for scholarly conferences. Here Alex provides some background to the work and asks for input from the community:

Roughly one year ago, Crossref and DataCite started a working group on conference and project identifiers. With this blog post, we would like to share the specification of conference metadata and Crossmark for proceedings and are inviting the broader community to comment.

Why are conferences important?

One common misbelief is that most published research appears in journals. However, next to new ways of communication research results (blogs, presentations,…) and journals there are also other publication options, like books, very important in humanities, or conference proceedings, which are very important in computer science and a couple of related disciplines. Conference proceedings are collections of journal-like papers, often undergoing a more competitive peer review process than in journals. For instance, looking at original research in computer science in Scopus published in CS in 2012-2016, 63% of articles appeared in proceedings, while only 37% were published in journals. DBLP, one of the most important indexing services in CS, lists more than two million conference papers organized in ~5,400 conference series.

So, while it is true that CS has a significant share of conference proceedings, conferences are also relevant in many other disciplines which do not publish formal proceedings. For instance, inSPIRE contains ~23,000 conferences in high-energy physics, the American Society of Mechanical Engineers (ASME) publishes roughly 100 proceedings volumes annually.

Why do we need an open persistent ID for a conference or a conference series?

With publishers, learned societies, indexing services, libraries, conference management systems, research evaluation and funding agencies using conferences directly or indirectly in their daily work, a common vocabulary would simplify data processing, reporting and minimize errors. Right now, a publisher assigns a unique conference ID to the conference to be published, then an indexing service does it, then it is assigned in a library. Wouldn’t it be easier to do this at the very beginning of the process, when the conference planning starts, and keep the same identifier through the whole conference lifecycle?

The joint Crossref and DataCite group on conference and project identifiers has discussed this topic at half a dozen calls and various PID community meetings (PIDapalooza, FORCE conferences, AAHEP Information Provider Summit). The result of those discussions is a draft of the specification of conference metadata and Crossmark for proceedings.

The document first defines the concepts of a conference, conference series, joint and co-located conferences. It then introduces the information we want to store about those entities, e.g., the ID, name, acronym, other IDs, URL and the maintainer of the conference series, or the ID, conf series ID, number, dates, location, and URL for conferences. Such metadata can be submitted to Crossref and DataCite by conference organizers or publishers on their behalf and linked to the existing proceedings metadata, where appropriate. It can be then used for linking research outputs from a conference (beyond formal proceedings), recognizing reviewers via services such as ORCID and Publons, computing metrics of a conference series, conference disambiguation in indexing services and ratings (CORE, QUALIS, CCF), and so on.

The second part of the document introduces Crossmark for conference proceedings. Its goal is to structure and preserve the information about the peer review process of a conference as declared by the general or program chairs. Depending on how much information is available from the conference organizers, one can use the basic or extended versions of Crossmark.

In order to comment, please open the specification and leave comments using “comment” feature of Google Docs. The draft remains open for comments till the 31st of May 2018.

Next steps

After hearing from YOU, we will update the document to reflect the community comments. In parallel, we start a subgroup discussing the governance models, looking into whether we need a new membership category at Crossref, what fees should be covered, etc.

A transparent record of life after publication

Madeleine Watson — Wed, 01 Nov 2017 00:00:00 +0000

Crossref Event Data and the importance of understanding what lies beneath the data.

Some things in life are better left a mystery. There is an argument for opaqueness when the act of full disclosure only limits your level of enjoyment: in my case, I need a complete lack of transparency to enjoy both chicken nuggets and David Lynch films. And that works for me. But metrics are not nuggets. Because in order to consume them, you really need to know how they’re made. Knowing the provenance of data, along with the context with which it was derived, provides everyone with the best chance of creating indicators which are fit for purpose. This is just one of the reasons why we built the Event Data infrastructure with transparency in mind.

The transparency problem

For the scholarly community, alternative metrics to citation count (‘altmetrics’) are becoming increasingly popular as they can offer rich and expedited insight into today’s diverse and dynamic research environment. Research artifacts undergo an extended life online as they’re linked, shared, saved and discussed in forums both within and beyond the traditional academic ecosystem. Data on these interactions are initially fragmented and buried within platforms like social media, blogs and news sites. Downstream, there are several value-add services that collate and present that data as a single, aggregated count. We see individual data points like ‘paper X was tweeted 22 times’, and ‘paper X is referenced 16 times on Wikipedia’ being combined, homogenised, weighted and expressed as a single figure, a calculated number serving as a proxy for value. But altmetrics alone don’t tell the whole story, and how they are calculated is not without idiosyncrasy or politics. As we each have our own unique voice and perspective, we need to ensure we understand the lenses through which these metrics are made in order to consume them effectively.

The 2015 Metric Tide report highlighted transparency as one of the five dimensions of responsible metrics. Having access to the context used to create a metric — the provenance of the original data as well as full transparency around its extraction, processing and aggregation — helps consumers to use the data meaningfully and allows for comparison across third-party vendors. But transparency is difficult to achieve when, as the report notes, the systems and infrastructure for collecting and curating altmetrics-style data are fragmented and have limited interoperability.

In the academic community, underlying centralised systems include ORCIDs to identify people and DOIs to identify items. But we’re missing a transparent, centralised infrastructure for describing and recording the relationships between objects and resources¹. These relationships, or links, occur outside publisher platforms and can provide valuable information about the interconnectivity and dissemination of research. Dedicated infrastructure for collecting these relationships would provide a data source for those interested in altmetrics to build upon.

Figure 1.1 Example of some relationships between articles and activity on the web

At Crossref, we call these relationships Events. An Event is the record of a claim made about the existence of a relationship between a registered content item (i.e. a DOI) and a specific activity on the web. Events include:

a DataCite dataset DOI contains a link to a Crossref article DOI
an article was referenced in Wikipedia
an article was mentioned on Twitter
an article has a Hypothes.is annotation
a blog contains a link to an article

In collaboration with DataCite, we are collecting Events for the DOIs registered with our organisations and are making that data available for others in the community to use. This is the Event Data infrastructure, with which we’re plugging the gap in open scholarly relationships infrastructure. https://doi.org/10.64000/kattr-5k219

The Event Data infrastructure

Crossref and DataCite have for many years provided a centralised location for bibliographic metadata and links, and a facility to help our members register Persistent Identifiers (DOIs) for their content. With nearly 100 million DOIs registered with Crossref, we know where research lives. Which got us thinking — could we use these links to find out more about the journey research undertakes after publication? Could we express these interactions as links without any aggregation or counts so it could be maximally reused? And if so, could we then provide this data in an open, centralised, structured format? The answer was yes, subject to some challenges:

Querying for individual DOIs wasn’t scalable for our full corpus of 100 million items, so we had to find something else.
Not everyone uses the DOI link (not a surprise!). Most people will link directly to the publisher’s site. This means we need to look for links using both the DOI and article landing page URLs.
When we find people referring to registered content using its landing page, we find the DOI for that content item so that the link can be referenced in our data set in a stable, link-rot-proof way.
We don’t always know the article landing page URL for every DOI upfront because like many relationships, the one between DOIs and URLs is complicated.

We began by asking the wrong questions and as a result we got the wrong type of data back: instead of returning a record of individual actions, we were returning aggregated counts. Aside from not meeting our use case, aggregation requires the curation of an ever-churning dataset in order to keep totals updated, which is not scalable for the number of DOIs in our corpus.

We soon learnt to ask the right questions. One pivotal change in approach was that instead of counts, we asked instead ‘what activity is happening on Twitter for this article?’. Our data went from ‘DOI X was mentioned 20 times on Twitter as of this date’ to ‘tweet X mentions DOI X on this date’. The data are now represented as a subject-verb-object triple:

Figure 1.2 Triple table.

Ultimately this has allowed us to represent actions like Wikipedia page edits as individual atomic actions (i.e an Event) rather than as a dataset that changes over time. Being open about the provenance of altmetrics with Event Data Crossref Event Data (the Crossref-specific service powered by the shared Event Data infrastructure) has evolved beyond a link store to become a continual stream of Events; each Event tells a new part of the story. Rather than constantly updating an Event whenever a new action takes place, we add a new one instead:

Figure 1.3 A Wikipedia Event.

Events answer a whole range of questions, such as:

What links to what?
How was the link made?
Which Agent collected the Event?
Which data source?
When was the link observed?
When do we think the link actually happened?
What algorithms were used to collect it?
Where’s the evidence?

We’re collecting data from a diverse range of platforms including Twitter, Wikipedia, blogs and news sites, Reddit, StackExchange, Wordpress.com and Hypothes.is. This means that when we observe a link in these platforms to what we think is a DOI, we create an Event and a corresponding Evidence Record to represent our observation. We also have Events to represent the links between research items registered with Crossref and DataCite - for example, when a Crossref DOI cites a DataCite DOI and vice versa.

The provenance of the data is fully transparent and is made available to everyone via an open API. We call this the evidence trail. The record of each link (‘Events’) as well as the corresponding evidence can then be used to feed into tools for impact measurement, discoverability, collaboration and network analysis.

Therefore, one application of Event Data is as an underlying, transparent data source for altmetrics calculations. For example, you might want to know the total number of times your paper has been mentioned on Twitter to date. If I told you that the number was 22, what does that actually mean? Do you know whether I counted both tweets and retweets? Do you consider both of these actions as equal? Is the sentiment of the tweet important to you? Was it a human or a bot that initiated a tweet? Are you interested in tweets containing links to multiple representations of your paper or do you only want to track mentions of your version of record (the final published copy)? With Event Data as your underlying data source, you can answer these questions.

Not only transparent in data, transparent by design

The National Information Standards Organisation (NISO), a US organisation responsible for technical standards for publishing, bibliographic and library applications, has developed a set of recommendations for transparency in their Alternative Assessment Metrics Project report, as well as a Code of Conduct for both altmetric practitioners and aggregators that aims to help improve the quality of altmetrics data. The working groups recognised that without transparency and conforming to a recognised standard, altmetric indicators “are difficult to assess, and thus may be seen as less reliable for purposes of measuring influence or evaluation”¹.

Crossref Event Data is one of the example altmetric data providers listed in the NISO recommendations. My colleague Joe Wass participated in the development and specification of the NISO “Altmetrics Recommended Practices on Data Metrics, Alternative Outputs, and Persistent Identifiers” at the same time as we were working with DataCite on Event Data, so they have mutually informed one another.

Figure 1.4 Martin Fenner (DataCite) and Joe Wass (Crossref) drawing plans for the Event Data infrastructure.

The outcome of our involvement in the NISO recommendations is that Crossref Event Data is a service that is transparent by design. We have opened up our entire extraction and processing workflow so that we can clearly demonstrate the context and environment that was used to generate an Event. This evidence is a core component of our transparency-first principle.

Building services on Event Data

There are some really exciting ways that people are already using Event Data, and we’re still only in beta. Our aim has always been to create an open, portable, transparent data set that can be used by our diverse community including researchers, application developers, publishers, funders and third-party service providers. We have already seen data from our service used in recent research studies, impact reports and even a front-end tool. Launched recently as a prototype, ImpactStory’s Paperbuzz.org uses Event Data as one of its data sources for tracking the online buzz around scholarly articles. Jason Priem, cofounder of ImpactStory, notes:

“Because Crossref Event Data is completely open data, we believe it’s a game-changer for altmetrics. Our latest project, Paperbuzz.org, is just the first of a whole constellation of upcoming tools that will add value on top of Crossref’s open data.”

We are working towards launching Crossref Event Data as a production service. In the meantime though, please do take a look at our comprehensive User Guide. Hopefully you’ll be inspired to go make something cool using the data! Events are being collected constantly; take a look below as they stream in from our data sources or visit our live stream demo site to watch in real time.

Figure 1.5 Screen capture of Crossref Event Data live stream demo.

As the service matures, we’ll continue to add new platforms to track and I also encourage anyone with article link data to get in touch to discuss how we can share it with the community via Event Data.

For researchers in particular, I’m really keen to hear your thoughts on our data model and about the things we could additionally provide you with from an infrastructure perspective that would best support your research needs.

And if you’re a publisher, take a look at our Event Data best practice guidelines — there’s some really important information in there about how you can help give us the best chance possible of collecting Events for your registered content.

And finally, if you’re a consumer of altmetrics data, I encourage you to ask questions. Ask your altmetrics vendors about how they gather their data and what context they apply to the aggregation of the metrics they supply. Ask yourself what behaviours you are interested in tracking and equally those you are not. Think about the endgame; about the type of impact you’re truly trying to measure and the story you want to tell. Because it’s these questions that will help you choose indicators that are the best fit for your own unique narrative.

This content is cross-posted on eLife Labs.

References

¹ Bilder, Geoffrey; Lin, Jennifer; Neylon, Cameron (2015): What exactly is infrastructure? Seeing the leopard’s spots. Retrieved: Oct 16, 2017; https://doi.org/10.6084/m9.figshare.1520432.v1

² NISO, Outputs of the NISO Alternative Assessment Metrics Project. Retrieved: 6th October 2017; https://www.niso.org/publications/rp-25-2016-altmetrics , p.2.

Organisation Identifier Working Group Update

Ed Pentz — Mon, 18 Sep 2017 00:00:00 +0000

About 1 year ago, Crossref, DataCite and ORCID [announced a joint initiative] (https://orcid.org/blog/2016/10/31/organisation-identifier-project-way-forward) to launch and sustain an open, independent, non-profit organisation identifier registry to facilitate the disambiguation of researcher affiliations. Today we publish governance recommendations and product principles and requirements for the creation of an open, independent organisation identifier registry and invite community feedback.

The organisation Identifier (OrgID) Working Group was established as a joint effort by Crossref, DataCite and ORCID in January 2017. The members of the group bring a broad range of experience and perspectives, including expertise in research data discovery, data management, persistent identifiers, economics research, funding, archiving, non-profit membership organisations, academia, publishing, and metadata development.

The Working Group was charged with refining the structure, principles, and technology specifications for an open, independent, non-profit organisation identifier registry to facilitate the disambiguation of researcher affiliations.

The group has been working in three interdependent areas: Governance, Registry Product Definition, and Business Model & Funding, and today releases for public comment its findings and recommendations for governance and product requirements.

We invite your feedback!

Please send comments by October 15th, 2017.

Event Data enters Beta

Jennifer Kemp — Wed, 05 Jul 2017 00:00:00 +0000

We’ve been talking about it at events, blogging about it on our site, living it, breathing it, and even sometimes dreaming about it, and now we are delighted to announce that Crossref Event Data has entered Beta.

A collaborative initiative by Crossref and DataCite, Event Data offers transparency around the way interactions with scholarly research occur online, allowing you to discover where it’s bookmarked, linked, liked, shared, referenced, commented on etc., across the web, and beyond publisher platforms.

The name Event Data reflects the nature of the service, as it collects and stores digital actions that occur on the web, from the quick and simple, such as bookmarking and referencing, through to deeper interconnectivity such as exposing the links between research artifacts. Each individual action is timestamped and recorded in our system as an Event, and made available to the community via an API.

Event Data will be available for absolutely anyone to use; publishers, third party vendors, editors, bibliometricans, researchers, authors, funders etc., and with tens of thousands of events occurring every day, there’s a wealth of insight to be gained for those interested in analyzing and interpreting the data.

It’s important to note that Event Data does not provide metrics. What is does provide is the raw data to help you facilitate your own analysis, giving you the freedom to integrate the data into your own systems.

We are currently working very closely with a few organisations with specific use cases who are helping us to test and refine Beta before we launch our production service later this year. If you decide to take a look at Beta yourself, all the data you collect from Event Data is licensed for public sharing and reuse according to our Terms of Use.

Until Event Data is in production mode, we do not recommend building any commercial or customer-based tools off the data. If you are not in the Beta test group but are interested in participating, please contact me below. For more information about Event Data, please see our user guide.

Please contact me, Jennifer Kemp—Outreach Manager for Event Data—with any questions.

Crossref and colleagues in South Korea

Ginny Hendricks — Fri, 30 Jun 2017 00:00:00 +0000

Connecting Crossref, ORCID, DataCite, and our communities

Q: What do you get if you combine our three organisations for a week to catch up with our Korean community - publishers, librarians, universities, researchers, and service providers? A: Two events, plenty of meetings, great conversations and feedback, fabulous Korean hospitality, and a little jet-lag.

Over the past few years, Crossref has seen huge growth in our members in Korea. We have nine Sponsoring Affiliates (who look after nearly 1,000 members between them), two Sponsoring Members and nearly 80 Library members. With the International DOI Foundation (IDF) strategy meeting taking place in Daejon, it seemed sensible to combine that with our own events and meetings with key organisations. This also fitted nicely with some plans that ORCID and DataCite had, so we combined forces.

We (that’s me, Rachael Lammey, Ed Pentz, and Geoffrey Bilder) hosted a Crossref LIVE local event on Monday 12th June for around 80 members and affiliates. We were joined by Alice Meadows and Nobuko Maiyairi (ORCID), Martin Fenner (DataCite), and Professor Sun-Tae Hong (Seoul National University) as co-presenters. We looked at the global reach of Korean research, and how registering content with Crossref and participating in services like Reference Linking helps create valuable connections between research outputs. With so many established members in Korea, we were able to go beyond the basics and emphasize the importance of metadata input, metadata delivery, and preview our upcoming Event Data service. We also talked data-sharing and the value of integrating ORCID iDs into publisher and institution workflows.

_Growth in research outputs in Asia Pacific 2009-2017. Source: Web of Science databases SCI-E, SSCI and AHCI only, downloaded 19/4/2017. Data provided by Wiley (thank you!)_

Later in the week we took a multi-pronged approach to highlight the many shared principles of our organisations and discuss the specific initiatives we’re collaborating on. We held the Joint Global Infrastructure Conference covering the global nature of what we do and the connections/interoperability between ORCID, DataCite and Crossref. This interoperability and our governance structures lend themselves to cooperation on other initiatives such as Metadata 2020 and The OI Project, which we were able to share.

Check out all #jgic_seoul tweets.

Guest speakers volunteered to talk about how they work with our organisations - we were joined by Choon Shil Lee from the Korean Association of Medical Journal Editors (KAMJE) to demonstrate their ORCID integrations, and Hideaki Takeda from the Japan Link Centre (JaLC) who discussed the infrastructure and services they use to register and disseminate content globally. User stories like this are great - they highlight how people work with our services, give others ideas, and also flag up where we can do more.

Part of doing more involved providing clarification on Crossref’s position alongside other DOI Registration Agencies. With a new Registration Agency in Korea, we needed to communicate the global nature of what we do to help our members achieve their discoverability goals, as not all DOIs are made equal. Through working with ORCID and DataCite colleagues we were able to place great importance both on our work worldwide, and on the benefits to Korean societies in collaborating outside national boundaries.

Combining talks from our three organisations was a great opportunity to emphasize the importance of shared global infrastructure. Geoffrey Bilder’s plug socket analogy is apt - services that work cross-border, cross-language, and cross-subject areas streamline processes for all of our different communities and enable research to travel beyond national boundaries and help it be found, linked, cited and assessed.

Want to find out more? Slides from both meetings are available here and here, and watch out for further collaborative events.

The OI Project gets underway planning an open organisation identifier registry

Ed Pentz — Tue, 28 Mar 2017 00:00:00 +0000

At the end of October 2016, Crossref, DataCite, and ORCID reported on collaboration in the area of organisation identifiers. We issued three papers for community comment and after input we subsequently announced the formation of The OI Project, along with a call for expressions of interest from people interested in serving on the working group.

We had a great response and are happy to report that the Working Group has now been established, and is already underway with work to develop a plan for an open, independent, not-for-profit, sustainable, organisation identifier registry.

There is information about the OI Project Working Group on the ORCID website including a list of the 17 working group members. They represent a broad range of scholarly communications stakeholders. Our scope of work includes three separate but interdependent areas:

Governance;
Registry Product Definition; and
Business Model & Funding.

The initial goal of the Working Group is to create a thorough and robust implementation plan by the end of 2017.

Please take a look at the website for more information and we’ll provide updates as things progress throughout the course of the year.

Please contact us with any questions.

Taking the "con" out of conferences

Geoffrey Bilder — Wed, 15 Feb 2017 00:00:00 +0000

TL;DR

Crossref and DataCite are forming a working group to explore conference identifiers and project identifiers. If you are interested in joining this working group and in doing some actual work for it, please contact us at community@crossref.org and include the text conference identifiers WG in the subject heading.

All the times I could have gone to Walt Disney World…

Back around 2010 I added a filter to my email settings that automatically flagged and binned any email that contained the word “Orlando.” Back then this was a remarkably effective way of detecting and ignoring spam from the numerous fake technology conferences that all seemed to advertise the city of Orlando, Florida as the location for their non-events. I suspected they all chose Orlando as it would provide the punter that little bit of extra motivation to pay and register for the conference as they simultaneously plotted how they could tag-on some holiday time at Walt Disney World. I finally had to remove the filter last year when I realised that the scammers had moved on to advertising more realistically gritty cities in their calls for submissions and that meanwhile I had managed to miss all the mail informing me of the ALA’s summer 2016 meeting held in, you guessed it… Orlando.

Clearly we need better mechanisms to flag dubious conferences.

Late last year Crossref’s Strategic initiatives group was approached by “CounterMock,” a group of Crossref members (including major proceedings publishers like Springer Nature, Elsevier, IEEE, ACM, IET, etc) who were actively exploring the establishment of an identifier system and registry for scholarly conferences.

The long term goal of the group is to make it easier for publishers, researchers and other stakeholders to identify fraudulent and/or low-quality conferences. There has recently been a proliferation of conferences that seem to have been developed specifically to dupe international and early-career researchers into paying substantial conference and publication fees. Sometimes these conferences are intentionally named after long-standing and well-respected conferences. At worst these conferences are entirely fake - no meetings are held and no publications are issued. At best they produce subpar publications of questionable academic integrity. Members of the group are concerned that these “mock conferences” (Hence “COUNTERMOCK”) will:

Waste researcher time.
Waste publisher time.
Undermine academic trust in conferences and conference proceedings as a trustworthy means of scholarly communication.

The group understands that the “evaluation of a conference quality” and the “unambiguous identification of conferences” are separate concerns (as they are with publications, contributors, etc). But they also realise that it will be hard to address the quality issue without an infrastructure for unambiguously identifying conferences and providing meaningful provenance metadata about those conferences. Moreover, having unique identifiers for conference series would enable a number of other applications. Examples include conference-level metrics, better and more structured info about forthcoming conferences on a certain topic, and more visibility of conferences in research evaluation.

Springer Nature has built a POC prototype of a conference identifier system and shown it to a number of other parties. The feedback has been that there is interest in the project, but that the consensus is that it should be managed a run by a neutral industry group. They have approached us to form a working group and explore how this project can be advanced.

This is all good. Crossref itself doesn’t make value judgements on the quality of content registered with us. Crossref DOIs are not quality marks. But we do believe that unambiguous identification of research artifacts is a perquisite to building effective trust and reputation tools.

It is possible that the issue of conference identifiers can be folded into the work we are doing with DataCite and ORCID on organisation identifiers. For example, some have argued that organisation identifiers should include identifiers for projects or other less formal and more ephemeral corporate entities that are often included in affiliation and/or bibliographic data. It is possible to make the similar arguments in the case of conferences.

On the other hand we have also been interested in the issue of “project identifiers.” Martin Fenner and Tom Demeranville have made a strong argument that ‘projects’ can be thought of as containers for collections of project outputs, project members and project funders. Again, it seems plausible that one could make the same case for conferences.

At the very least it is important to coordinate any work that is done on conference, project and organisation identifiers. This why we have decided to form a joint Crossref/DataCite working group to specifically explore conference and project identifiers and determine how they relate both to each other and to our already ongoing work with ORCID on organisation identifiers.

Additionally, it is likely that the working group will discuss and explore how conference/project identifiers might be used for increasing the transparency of peer review at conferences, better attribution for programme chairs and program committee members, and how they might be incorporated into other services like Crossref Metadata Search, DataCite search, CrossMark, etc.

If you are interested in doing some work on this- then please indicate your interest in joining a working group by sending email to community@crossref.org and include the text conference identifiers WG in the subject heading.

We will update this blog as the group convenes and makes progress.

The Organisation Identifier Project: a way forward

Ed Pentz — Mon, 31 Oct 2016 00:00:00 +0000

The scholarly communications sector has built and adopted a series of open identifier and metadata infrastructure systems to great success. Content identifiers (through Crossref and DataCite) and contributor identifiers (through ORCID) have become foundational infrastructure to the industry.

But there still seems to be one piece of the infrastructure that is missing. There is as yet no open, stakeholder-governed infrastructure for organisation identifiers and associated metadata.

In order to understand this gap, Crossref, DataCite and ORCID have been collaborating to:

Explore the current landscape of organisational identifiers;
Collect the use-cases that would benefit our respective stakeholders in scholarly communications industry;
Identify those use-cases that can be more feasibly addressed in the near term; and
Explore how the three organisations can collaborate (with each other and with others) to practically address this key missing piece of scholarly infrastructure.

The result of this work is in three related papers being released by Crossref, DataCite and ORCID for community review and feedback. The three papers are:

organisation Identifier Project: A Way Forward (PDF; GDoc)
organisation Identifier Provider Landscape (PDF; GDoc)
Technical Considerations for an organisation Identifier Registry (PDF; GDoc)

We invite the community to comment on these papers both via email (oi-project@orcid.org) and at PIDapalooza on November 9th and 10th and at Crossref LIVE16 on November 1st and 2nd. To move The OI Project forward, we will be forming a Community Working Group with the goal of holding an initial meeting before the end of 2016. The Working Group’s main charge is to develop a plan to launch and sustain an open, independent, non-profit organisation identifier registry to facilitate the disambiguation of researcher affiliations.

Crossref Use Cases

Crossref has also been discussing the needs of its members over the last year and there is value in focusing on the affiliation name ambiguity problem with research outputs and contributors. In terms of the metadata that Crossref collects, something that is missing has been affiliations for the authors of publications. Over the last couple of years, Crossref has been expanding what it collects - for example, funding and licensing data and ORCID iDs - and this enables a fuller picture of what we are calling the article nexus. In order to continue to fill out the metadata we collect - and for our members to use in their own systems and publications - we need an organisation identifier.

Another use case for Crossref is identifying funders as part of collecting funder data to enable connecting funding sources with the published scholarly literature. In order to enable the reliable identification of funders in the Crossref system we created the Open Funder Registry that now has over 15,000 funders available as Open Data under a CC0 waiver. While this has been very successful, it is a very narrowly focused registry and is not suitable for a broad, community-run organisation identifier registry that addresses the affiliation use case. In future, our goal will be to merge the Open Funder Registry into the identifier registry that the organisation Identifier Working Group will work on.

By working collaboratively we can define a pragmatic and cost-effective service that will meet a fundamental need of all scholarly communication stakeholders.

Geoffrey Bilder will be focusing his talk at Crossref LIVE16 this week on this initiative, dubbed The OI Project. The talk is scheduled for 2pm UK time and will be live streamed along with the rest of that day’s program.

Linking Publications to Data and Software

Jennifer Lin — Wed, 07 Sep 2016 00:00:00 +0000

TL;DR

Crossref and Datacite provide a service to link publications and data. The easiest way for Crossref members to participate in this is to cite data using DataCite DOIs and to include them in the references within the metadata deposit. These data citations are automatically detected. Alternatively and/or additionally, Crossref members can deposit data citations (regardless of identifier) as a relation type in the metadata. Data & software citations from both methods are freely propagated. This blog post also describes how to retrieve the links collected between publication and data & software.

Data & software citation is good research practice (DataCite-STM Joint Statement and FORCE11 Joint Declaration of Data Citation Principles) and is part of the scholarly ecosystem supporting research validation and reproducibility. Data & software citation is also instrumental in enabling the reuse and verification of these research outputs, tracking their impact, and creating a scholarly structure that recognises and rewards those involved in producing them.

Crossref supports the propagation of data & software citations alongside a publisher’s standard bibliographic metadata. members deposit the data citation link as part of the overall publication metadata when registering their content. Crossref partners with DataCite and together, we jointly provide a clearinghouse for the citations collected. These are all made freely available to the community as open data.

Citation practices are evolving across different communities of practice. Crossref’s offering is flexible and easily accommodates variations and changes, since it does not rely on a specific set of citation metadata elements, citation format, nor manner of credit and attribution. Publishers deposit data & software citations in their metadata deposit via a) references and/or b) relation type.

Method A: Bibliographic references

Crossref and DataCite have partnered to provide automatic linking between publications registered with Crossref and datasets bearing DataCite DOIs. This is the most efficient and effective way to ensure that data citations are fully integrated into the scholarly research information network with full and accurate metadata.

All data & software citations that include datasets bearing a DataCite DOI are eligible for auto-update linking with Crossref. In this method: authors cite the dataset or software containing the DataCite DOI per journal article submission guidelines and add it to the article citation list (c.f. FORCE11 citation placement, FORCE11 Software Citation Principles). Publishers then deposit references as part of their standard practice when registering content. Crossref checks every reference deposited for a DOI. If the DOI is identified as DataCite’s, we automatically link it to the article. With this method, no additional action is needed when publishers register their content with Crossref.

Data citation links to non-DataCite DOIs can only be exposed in the references if the publisher makes references openly available. Even in the event that the data citation is shared, it remains undifferentiated from other references. Method B described below offers another approach.

Method B: Relation type

Publishers can link their publication to a variety of associated research objects as part of the article metadata directly in the metadata deposited to Crossref, including data & software, protocols, videos, published peer reviews, preprints, conference papers, etc. Doing so not only groups digital objects together, but formally associates them with the publication. Each link is a relationship and the sum of all these relationships constitutes a ‘research article nexus.’ Data & software citations are a valuable part of this.

To tag the citation in the metadata deposit, we ask for:

description of dataset or software (optional)

dataset or software identifier

identifier type

relationship type.

Crossref can accommodate research outputs with any identifier, though we currently only validate DOI relationships during metadata processing. Technical details are documented in the [Data & Software Citations Deposit Guide][4].

Combining methods increases total available citations

The two methods are independent and can be used exclusively or jointly. Each caters to a different set of conditions and their practical considerations. See the comparison of benefits and limitations for each method in the deposit guide. We recommend that publishers use both methods where possible at this time for optimum specificity and coverage.

How to access data & software citations

Crossref and DataCite make the data & software citations deposited by Crossref members and DataCite data repositories openly available to a wide host of parties, including both Crossref and DataCite communities as well as the extended research ecosystem (funders, research organisations, technology and service providers, research data frameworks such as Scholix, etc.).

Data & software citations from references can be accessed via the Crossref Event Data API Citations included directly into the metadata by relation type can be accessed via Crossref’s APIs in a number of formats (REST, OAI-PMH, OpenURL). (A single channel containing data & software citations across interfaces is in development and will be released next year.)

Publishers, visit our detailed guide on how to deposit data and software citations. We welcome your questions and concerns at feedback@crossref.org.

Special thanks to the following who provided valuable feedback in developing the guide: Martin Fenner (DataCite), Amye Kenall (Springer Nature), Brooks Hanson (AGU), Shelley Stall (AGU), and the FORCE11 Data Citation Implementation Pilot publisher’s subgroup.

Announcing PIDapalooza - a festival of identifiers

Ginny Hendricks — Tue, 30 Aug 2016 00:00:00 +0000

The buzz is building around PIDapalooza - the first open festival of scholarly research persistent identifiers (PID), to be held at the Radisson Blu Saga Hotel Reykjavikon November 9-10, 2016.

PIDapalooza will bring together creators and users of PIDs from around the world to shape the future PID landscape through the development of tools and services for the research community. PIDs support proper attribution and credit, promote collaboration and reuse, enable reproducibility of findings, foster faster and more efficient progress, and facilitate effective sharing, dissemination, and linking of scholarly works.

We believe that by bringing together everyone who’s working with PIDs for two days of discussions, demos, workshops, brainstorming, updates on the state of the art, and more, we can make this happen faster. And you can help by giving us your input on which sessions would be most valuable. Please send us your ideas, using this form by September 18. We will send session proposal notifications the first week of October with the festival lineup.

Register to attend

Registration is now open — come join the festival with a crowd of like-minded innovators. And please help us spread the word about PIDapalooza in your community!

Stay updated with the latest news on on the PIDapalooza website and on Twitter (@PIDapalooza) in the coming weeks.

Looking forward to seeing you in November!

Crossref Event Data: early preview now available

Madeleine Watson — Mon, 18 Apr 2016 00:00:00 +0000

Test out the early preview of Event Data while we continue to develop it. Share your thoughts. And be warned: we may break a few eggs from time to time!

Chicken by anbileru adaleru from the The Noun Project

Want to discover which research works are being shared, liked and commented on? What about the number of times a scholarly item is referenced? Starting today, you can whet your appetite with an early preview of the forthcoming Crossref Event Data service. We invite you to start exploring the activity of DOIs as they permeate and interact with the world after publication.

But first, a bit of background

Discussion around scholarly research increasingly occurs online after publication, for example on blogs, sharing services, social media, and wikis. These ‘events’ occur across the web on numerous platforms and are a critical part of the scholarly enterprise. We are developing an infrastructure service (Crossref Event Data) that collects, stores, and delivers raw data of the events occurring with Crossref DOIs. We will store the data in an open, auditable and portable form for the community to access. Publishers, platforms, funders, bibliometricians and service providers may benefit from access to this raw data, and it can be used to feed into research records or proprietary tools and services that offer aggregation and analysis.

For more information, see our pilot blog post and description of potential use cases.

Collaborative, transparent development

Developers Martin Fenner (DataCite) and Joe Wass (Crossref) enjoy a tofu break

Lagotto, the software originally developed at PLOS, has been extended and improved in a joint effort between DataCite and Crossref. The two DOI Registration Agencies have partnered to envision, build and release the service. On the 13th of April, after a year of collaboration, we jointly released Lagotto 5.0. You can read about the collaboration on the DataCite blog post.

Crossref and DataCite will continue to work closely together to develop Lagotto and the Event Data service. Although Crossref Event Data has mostly Crossref DOIs at launch, you will be able to find DataCite DOIs if they are cited in Crossref or Wikipedia.

All of the software that runs Event Data, including Lagotto, is developed in the open and is open source. Please refer to the Crossref Event Data Technical User Guide for full details.

Preview the data

This service is currently under development with a full launch expected the second half of 2016. Before it is launched however, we invite you to take a look around and preview a subset of the data sources we plan to include. You may experience occasional hiccups while we continue building the service.

At this stage, we are working with data from three sources although we will greatly expand the variety of platforms from which we collect data as development progresses. At this stage, you can view Mendeley bookmarks, Wikipedia references, and Crossref to DataCite links.

Mendeley

Mendeley is a reference manager and academic social network for scholars. View the number of social bookmarks from scholars or groups on Mendeley.

For example, doi.org/10.1016/J.JIP.2016.03.007 currently has 8 readers on Mendeley to date.

Wikipedia

Wikipedia is an online encyclopaedia, the Internet’s largest and most popular general reference work. View references in Wikipedia of Crossref publications in Wikipedia articles in all languages.

For example, doi.org/10.3897/ZOOKEYS.565.7185 was referenced in the Russian Wikipedia page on Oxyscelio

Crossref to DataCite links

DataCite is a global consortium that assigns DOIs to research data. This enables people to find, share, use, and cite data. You can view all the data citations to DataCite research outputs found in Crossref publications (work is underway to make the links found in DataCite metadata available in Event Data).

For example, Global, Regional, and National Fossil-Fuel CO2 Emissions (doi.org/10.3334/CDIAC/00001) dataset has been referenced by six Crossref publications to date. Software links are also included. Another example is PGOPHER (doi.org/10.5523/bris.huflggvpcuc1zvliqed497r2), a general purpose software for simulating and fitting rotational, vibrational and electronic spectra, which has been referenced by seven Crossref publications to date.

Ready to take a spin?

You can explore the Crossref Event Data early preview by visiting http://eventdata.crossref.org and following the links to featured examples within our interim application for inspecting the data, technical documentation, and our Quick Start guide.

This service is currently under development and as such we welcome your thoughts and feedback on the data we are collecting currently from our three active sources. As a reminder, we expect to include the following sources as part of our full service launch later this year (pending confirmation):

[table id=1 /]

We’re also on the lookout for new data sources to investigate for future inclusion in the Event Data service so please do get in touch with requests and recommendations. As we continue to build the service throughout 2016, we will be committing to a model of continuous development so that we can make new sources available as they are completed.

Watch this blog for regular updates on our progress, or subscribe to receive new blog posts by email (just add your details to the upper right side of this page).

Auto-Update Has Arrived! ORCID Records Move to the Next Level

Rachael Lammey — Mon, 26 Oct 2015 00:00:00 +0000

Crossref goes live in tandem with DataCite to push both publication and dataset information to ORCID profiles automatically. All organisations that deposit ORCID iDs with Crossref and/or DataCite will see this information going further, automatically updating author records.

We’re cross-posting ORCID’s blog below with all the details:

Since ORCID’s inception, our key goal has been to unambiguously identify researchers and provide tools to automate the connection between researchers and their creative works. We are taking a big step towards achieving this goal today, with the launch of Auto-Update functionality in collaboration with Crossref and [DataCite](https://www.datacite.org/.

There’s already been a lot of excitement about Auto-Update: Crossref’s recent announcement about the imminent launch generated a flurry of discussion and celebration on social media. Our own tweet on the topic was viewed over 10,500 times and retweeted by 60 other accounts.

So why all the fuss? We think Auto-Update will transform the way researchers manage their scholarly record. Until now, researchers have had to manually maintain their record, connecting new activities as they are made public. In ORCID, that meant using Search & Link tools developed by our member organisations to claim works manually. Researchers frequently ask, “Why, if I include my ORCID iD when I submit a manuscript or dataset, isn’t my ORCID record “automagically” updated when the work is published?”

With the launch of Auto-Update, that is just what will happen.

It might seem like magic but there are a few steps to make it work:

Researchers. You need to do two things: (1) use your ORCID iD when submitting a paper or dataset, and (2) authorize Crossref and DataCite to update your ORCID record. In keeping with our commitment to ensuring that researchers maintain full control of their ORCID record, you may revoke this permission at any time, and may also choose privacy settings for the information posted on your record.

Publishers and data centers. These organisations also have two things to do: (1) collect ORCID identifiers during the submission workflow, using a process that involves authentication (not a type-in field!), and (2) embed the iD in the published paper and include the iD when submitting information to Crossref or DataCite.

Crossref and DataCite. Upon receipt of data from a publisher or data center with a valid identifier, Crossref or DataCite can automatically push that information to the researcher’s ORCID record.

More information about how to opt out of this service can be found here: the ORCID Inbox.

Why is this so revolutionary?

A bit of background, first. Crossref and DataCite, both non-profit organisations, are leaders in minting DOIs (Digital Object Identifiers) for research publications and datasets. A DOI is a unique alphanumeric string assigned to a digital object – in this case, an electronic journal article, book chapter, or a dataset. Each DOI is associated with a set of basic metadata and a URL pointer to the full text, so that it uniquely identifies the content item and provides a persistent link to its location on the internet.

Crossref, working with over a thousand scholarly publishers, has generated well over 75 million DOIs for journal articles and book chapters. DataCite works with nearly 600 data centers worldwide and has generated over 6.5 million DOIs to date. Between them, Crossref and DataCite have already received almost a half a million works from publishers and data centers that include an ORCID iD validated by the author/contributor. With Auto-Update functionality in place, information about these articles can transit (with the author’s permission) to the author’s ORCID record.

Auto-Update doesn’t stop at a researcher’s ORCID record. Systems that have integrated ORCID APIs and have a researcher’s ORCID record connected to that system — their faculty profile system, library repository, webpage, funder reporting system — can receive alerts from ORCID. Information can move easily and unambiguously across systems.

This is the beginning of the end for the endless rekeying of information that plagues researchers — and anyone involved in research reporting. Surely something to celebrate!

Questions you may have:

Q. What do I need to do to sign up for auto-update?

You need to grant permission to Crossref and DataCite to post information to your ORCID record. You can do this today by using the Search and Link wizard for DataCite available through the ORCID Registry or the DataCite Metadata Search page. We also have added a new ORCID Inbox, so that you can receive a message from Crossref or DataCite if they receive a datafile with your iD, and you can grant permission directly. See More on the ORCID Inbox.

Q. Will Crossref and DataCite be able to update my ORCID record with already published works for which I did not use my ORCID iD?

No. The auto-update process only applies to those works that these organisations receive that include your ORCID iD. For previous works that did not include your ORCID iD, you will need to use the DataCite and Crossref Search and Link wizards to connect information with your iD.

Q. What information will be posted to my record?

With your permission, basic information about the article (such as title, list of contributors, journal or publisher) or dataset (such as data center name and date of publication) will be posted, along with a DOI that allows users to navigate to the source paper or dataset landing page.

Q. What if my journal or data center doesn’t collect ORCID iDs?

Ask them to! This simple step can be accomplished using either the Public or Member ORCID APIs. Information about integrating ORCID iDs in publishing and repository workflows is publicly available.

January 2015 DOI Outage: Followup Report

Geoffrey Bilder — Tue, 17 Mar 2015 00:00:00 +0000

Background

On January 20th, 2015 the main DOI HTTP proxy at doi.org experienced a partial, rolling global outage. The system was never completely down, but for at least part of the subsequent 48 hours, up to 50% of DOI resolution traffic was effectively broken. This was true for almost all DOI registration agencies, including Crossref, DataCite and mEDRA.

At the time we kept people updated on what we knew via Twitter, mailing lists and our technical blog at CrossTech. We also promised that, once we’d done a thorough investigation, we’d report back. Well, we haven’t finished investigating all implications of the outage. There are both substantial technical and governance issues to investigate. But last week we provided a preliminary report to the Crossref board on the basic technical issues, and we thought we’d share that publicly now.

The Gory Details

First, the outage of January 20th was not caused by a software or hardware failure, but was instead due to an administrative error at the Corporation for National Research Initiatives (CNRI). The domain name “doi.org” is managed by CNRI on behalf of the International DOI Foundation (IDF). The domain name was not on “auto-renew” and CNRI staff simply forgot to manually renew the domain. Once the domain name was renewed, it took about 48 hours for the fix to propagate through the DNS system and for the DOI resolution service to return to normal. Working with CNRI we analysed traffic through the Handle HTTP proxy and here’s the graph:

The above graph shows traffic over a 24 hour period on each day from January 12, 2015 through February 10th, 2015. The heavy blue line for January 20th and the heavy red line for January 21st show how referrals declined as the doi.org domain was first deleted, and then added back to DNS.

It could have been much worse. The domain registrar (GoDaddy) at least had a “renewal grace and registry redemption period” which meant that even though CNRI forgot to pay its bill to renew the domain, the domain was simply “parked” and could easily be renewed by them. This is the standard setting for GoDaddy. Cheaper domain registrars might not include this kind of protection by default. Had there been no grace period, then it would have been possible for somebody other than CNRI to quickly buy the domain name as soon as it expired. There are many automated processes which search for and register recently expired domain names. Had this happened, at the very least it would have been expensive for CNRI to buy the domain back. The interruption to DOI resolutions during this period would have also been almost complete.

So we got off relatively easy. The domain name is now on auto-renew. The outage was not as bad as it could have been. It was addressed quickly and we can be reasonably confident that the same administrative error will not happen again. Crossref even managed to garner some public praise for the way in which we handled the outage. It is tempting to heave a sigh of relief and move on.

We also know that everybody involved at CNRI, the IDF and Crossref have felt truly dreadful about what happened. So it is also tempting to not re-open old wounds.

But it would be a mistake if we did not examine a fundamental strategic issue that this partial outage has raised: How can Crossref claim that its DOIs are ‘persistent’ if Crossref does not control some of the key infrastructure on which it depends? What can we do to address these dependencies?

What do we mean by “persistent?”

@kaythaney tweets on definition of “persistent”

To start with, we should probably explore what we mean by ‘persistent’. We use the word “persistent” or “persistence” about 470 times on the Crossref web site. The word “persistent” appears central to our image of ourselves and of the services that we provide. We describe our core, mandatory service as the “Crossref Persistent Citation Infrastructure.”

The primary sense of the word “persistent” in the New Oxford American Dictionary is:

Continuing firmly or obstinately in a course of action in spite of difficulty or opposition.

We play on this sense of the word as a synonym for “stubborn” when we half-jokingly say that, “Crossref DOIs are as persistent as Crossref staff.” Underlying this joke is a truth, which is that persistence is primarily a social issue, not a technical issue.

Yet presumably we once chose to use the word “persistent” instead of “perpetual” or “permanent” for other reasons. “Persistence” implies longevity, without committing to “forever.” Scholarly publishers, perhaps more than most industries, understand the long term. After all, the scholarly record dates back to at least 1665 and we know that the scholarly community values even our oldest journal backfiles. By using the word “persistent” as opposed to the more emphatic “permanent” we are essentially acknowledging that we, as an industry, understand the complexity and expense of stewarding the content for even a few hundred years to say nothing of “forever.” Only the chronologically naïve would recklessly coin terms like “permalink” for standard HTTP links which have a documented half-life of well under a decade.

So “persistent” implies longevity- without committing to forever- but this still begs questions. What time span is long enough to qualify as “persistent?” What, in particular, do we mean by “persistent” when we talk about Crossref’s “Persistent Citation Infrastructure?” or of Crossref DOIs being “persistent identifiers?”

What do we mean by “persistent identifiers?”

]5 @violetailik tweets on outage and implication for term “persistent identifier”

First, we often make the mistake of talking about “persistent identifiers” as if there is some technical magic that makes them continue working when things like HTTP URIs break. The very term “persistent identifier” encourages this kind of magical thinking and, ideally, we would instead talk about “persist-able” identifiers. That is, those that have some form of indirection built into them. There are many technologies that do this- Handles, DOIs, Purls, ARKs and every URL shortener in existence. Each of them simply introduces a pointer mapping between an identifier and location where a resource or content resides. This mapping can be updated when the content moves, thus preserving the link. Of course, just because an identifier is persist-able doesn’t mean it is persistent. If Purls or DOIs are not updated when content moves, then they are no more persistent than normal URLs.

Andrew Treloar points out that when we talk about “persistent identifiers,” we tend to conflate several things:

The persistence of the identifier- that is the token or string itself.
The persistence of the thing being pointed at by the identifier. For example, the content.
The persistence of the mapping of the identifier to the thing being identified.
The persistence of the resolver that allows one to follow the mapping of the identifier to the thing being identified.
The persistence of a mechanism for updating the mapping of the identifier to the thing being identified.

If any of the above fails, then “persistence” fails. This is probably why we tend to conflate them in the first place.

Each of these aspects of “persistence” is worthy of much closer scrutiny, however, in the most recent case of the January outage of “doi.org,” the problem specifically occurred with item “D”- the persistence of the resolver. When CNRI failed to renew the domain name for “doi.org” on time, the DOI resolver was rendered unavailable to a large percentage of people over a period of about 48 hours as global DNS servers first removed, and then added back the “doi.org” domain.

Turtles all the way down*

The initial public reaction to the outage was, almost unanimous in one respect- people assumed that the problem originated with Crossref.

@iainh_z tweets to Crossref enquiring about failed DOI resoluton

@LibSkrat tweets at Crossref about DOI outage

This is both surprising and unsurprising. It is surprising because we have fairly recent data indicating that lots of people recognise the DOI brand, but not the Crossref brand. Chances are, that this relatively superficial “brand” awareness does not correlate with understanding how the system works or how it relates to persistence. It is likely plenty of people clicked on DOIs at the time of the outage and, when they didn’t work, simply shrugged or cursed under their breath. They were aware of the term ‘DOI’ but not of the promise of “persistence”. Hence, they did not take to twitter to complain about it, and if they did, they probably wouldn’t have known who to complain to or even how to complain to them (neither CNRI or the IDF has a Twitter account).

But the focus on Crossref is also unsurprising. Crossref is by far the largest and most visible DOI Registration Agency. Many otherwise knowledgeable people in the industry simply don’t know that there are even other RAs.

They also generally didn’t know of the strategic dependencies that exist in the Crossref system. By “strategic dependencies” we are not talking about the vendors, equipment and services that virtually every online enterprise depends on. These kinds of services are largely fungible. Their failures may be inconvenient and even dramatic, but they are rarely existential.

Instead we are talking about dependencies that underpin Crossref’s ability to deliver on its mission. Dependencies that not only affect Crossref’s operations, but also its ability to self-govern and meet the needs of its membership. In this case there are three major dependencies: Two of which are specific to Crossref and other DOI registration agencies and one which is shared by virtually all online enterprises today. The organisations are: The International DOI Foundation (IDF), Corporation for National Research Initiatives (CNRI) and the Internet Corporation for Assigned Names and Numbers (ICANN).

Dependency of RAs on IDF, CNRI and ICANN. Turtles all the way down.

Each of these agencies has technology, governance and policy impacts on Crossref and the other DOI registration agencies, but here we will focus on the technological dependencies.

At the top of the diagram are a subset of the various DOI Registration Agencies. Each RA uses the DOI for a particular constituency (e.g. scholarly publishers) and application (e.g. citation). Sometimes these constituencies/applications overlap (as with mEDRA, Crossref and DataCite), but sometimes they are orthogonal to the other RAs, as is the case with EIDR. All, however, are members of the IDF.

The IDF sets technical policies and development agendas for the DOI infrastructure. This includes recommendations about how RAs should display and link DOIs. Of course all of these decisions have an impact on the RAs. However, the IDF provides little technical infrastructure of its own as it has no full-time staff. Instead it outsources the operation of the system to CNRI, this includes the management of the doi.org domain which the IDF owns.

The actual DOI infrastructure is hosted on a platform called the Handle System which was developed by and is currently run by CNRI. The Handle System is part of a quite complex and sophisticated platform for managing digital objects that was originally developed for DARPA. A subset of the Handle system is designated for use by DOIs and is identified by the “10” prefix (e.g. 10.5555/12345678). The Handle system itself is not based on HTTP (the web protocol). Indeed, one of the much touted features of the Handle System is that it isn’t based on any specific resolution technology. This was seen as a great virtue in the late 1990s when the DOI system was developed and the internet had just witnessed an explosion of seemingly transient, competing protocols (e.g. Gopher, WAIS, Archie, HyperWave/Hyper-G, HTTP, etc.). But what looked like a wild-west of protocols quickly settled into an HTTP hegemony. In practice, virtually all DOI interactions with the Handle system are via HTTP and so, in order to interact with the web, the Handle System employs a “Handle proxy” which translates back and forth between HTTP, and the native Handle system. This all may sound complicated, and the backend of the Handle system is really very sophisticated, but it turns out that the DOI really uses only a fraction of the Handle system’s features. In fact, the vast majority of DOI interactions merely use the Handle system as a giant lookup table which allows one to translate an identifier into a web location. For example, it will take a DOI Handle like this:

10.5555/12345678

and redirect it to (as of this writing) the following URL:

http://psychoceramics.labs.crossref.org/10.5555-12345678.html

This whole transformation is normally never seen by a user. It is handled transparently by the web browser, which does the lookup and redirection in the background using HTTP and talking to the Handle Proxy. In the late 1990s, even doing this simple translation quickly, at scale with a robust distributed infrastructure, was not easy. These days however we see dozens if not hundreds of “URL Shorteners” doing exactly the same thing at far greater scale than the Handle System.

It may seem a shame that more of the Handle Systems features are not used, but the truth is the much touted platform independence of the Handle System rapidly became more of a liability and impediment to persistence than an aid. To be blunt, if in X years a new technology comes out that supersedes the web, what do we think the societal priority is going to be?

To provide a robust and transparent transition from the squillions of existing HTTP URI identifiers that the entire world depends on?
To provide a robust and transparent transition from the tiny subset of Handle-based identifiers that are used by about a hundred million specialist resources?

Quite simply, the more the Handle/DOI systems diverge from common web protocols and practice, then the more we will jeopardise the longevity of our so-called persistent identifiers.

So, in the end, DOI registration agencies really only use the Handle system for translating web addresses. All of the other services and features one might associate with DOIs (reference resolution, metadata lookup, content negotiation, OAI-PMH, REST APIs, Crossmark, CrossCheck, TDM Services, FundRef etc) are all provided at the RA level.

But this address resolution is still critical. And it is exactly what failed for many users on January 20th 2015. And to be clear, it wasn’t the robust and scaleable Handle System that failed. It wasn’t the Handle Proxy that failed. And it certainly wasn’t any RA-controlled technology that failed. These systems were all up and running. What happened was that the standard handle proxy that the IDF recommends RAs use, “dx.doi.org”, was effectively rendered invisible to wide portions the internet because the “doi.org” domain was not renewed. This underscores two important points.

The first is that it doesn’t much matter what precisely caused the outage. In this case it was an administrative error. But the effect would have been similar if the Handle proxies had failed of if the Handle system itself had somehow collapsed. In the end, Crossref and all DOI registration agencies are existentially dependent on the Handle system running and being accessible.

The second is that the entire chain of dependencies from the RAs down through CNRI are also dependent on the DNS system which, in turn, is governed by ICANN. We should really not be making too much of the purported technology independence of the DOI and Handle systems. To be fair, this limitation is inherent to all persistent identifier schemes that aim to work with the web. It really is “turtles all the way down.”

What didn’t fail on January 19th/20th and why?

You may have noticed a lot of hedging in our description of the outage of January 19th/20th. For one thing, we use the term “rolling outage.” Access to the Handle Proxy via “dx.doi.org” was never completely unavailable during the period. As we’ve explained, this is because the error was discovered very quickly and the domain was renewed hours after it expired. The nature of DNS propagation meant that even as some DNS servers were deleting the “doi.org” entry, others were adding it back to their tables. In some ways this was really confusing because it meant it was difficult to predict where the system was working and where it wasn’t. Ultimately it all stabilised after the standard 48-hour DNS propagation cycle.

But there were also some Handle-based services that simply were not affected at all by the outage. During the outage, a few people asked us if there was an alternative way to resolve DOIs. The answer was “yes,” there were several. It turns out that “doi.org” is not the only DNS name that points to the Handle Proxy. People could easily substitute “dx.doi.org” with “dx.crossref.org” or “dx.medra.org” or “hdl.handle.net” and “resolve” any DOI. Many of Crossref’s internal services use these internal names and so the services continued to work. This is partly why we only discovered the “doi.org” was down from people reporting it on Twitter.

And, of course, there were other services that were not affected by the outage. Crossmark, the REST API, and Crossref Metadata Search all continued to work during the outage.

Protecting ourselves

So what can we do to reduce our dependencies and/or the risks intrinsic to those dependencies?

Obviously, the simplest way to have avoided the outage would have been to ensure that the “doi.org” domain was set to automatically renew. That’s been done. Is there anything else we should do? A few ideas have been floated that might allow us to provide even more resilience. They range greatly in complexity and involvement.

Provide well-publicised public status dashboards that show what systems are up and which clearly map dependencies so that people could, for instance, see that the doi.org server was not visible to systems that depended on it. Of course, if such a dashboard had been hosted at doi.org, nobody would have been able to connect to it. Stoopid turtles.
Encourage DOI RAs to have the members point to Handle proxies using domain names under the RA’s control. Simply put, if Crossref members had been using “dx.crossref.org” instead of “dx.doi.org”, then Crossref DOIs would have continued to work throughout the outage of “doi.org”. The same with mEDRA, and the other RAs. This way each RA would have control over another critical piece of their infrastructure. It would also mean that if any single RA made a similar domain name renewal mistake, the impact would be isolated to a particular constituency. Finally, using RA-specific domains for resolving DOIs might also make it clear that different DOIs are managed by different RAs and might have different services associated with them. Perhaps Crossref would spend less time supporting non-Crossref DOIs?
Provide a parallel, backup resolution technology that could be pointed to in the event of a catastrophic Handle System failure. For example we could run a parallel system based on PURLs, ARKs or another persist-able identifier infrastructure.
Explore working with ICANN to get the handle resolvers moved under the special “.arpa” top level domain (TLD). This TLD (RFC 3172) is reserved for services that are considered to be “critical to the operation of the internet.” This is an option that was first discussed at a meeting of persistent identifier providers in 2011.

These are all tactical approaches to addressing the specific technical problem of the Handle System becoming unavailable, but they do not address deeper issues relating to our strategic dependence on several third parties. Even though the IDF and CNRI provide us with pretty simple and limited functionality, that functionality is critical to our operations and our claim to be providing persistent identifiers. Yet these technologies are not in our direct control. We had to scramble to get hold of people to fix the problem. For a while, we were not able to tell our users or members what was happening because we did not know ourselves.

The irony is that Crossref was held to account, and we were in the firing line the entire time. Again, this was almost unavoidable. In addition to being the largest DOI RA, we are also the only RA that has any significant social media presence and support resources. Still, it meant that we were the public face of the outage while the IDF and CNRI remained in the background.

And this is partly why our board has encouraged us to investigate another option:

Explore what it would take to remove Crossref dependencies on the IDF and CNRI.

Crossref is just part of a chain of dependencies the goes from our members down through the IDF, CNRI and, ultimately, ICANN. Our claim to providing a persistent identifier structure depends entirely on the IDF and CNRI. Here we have explored some of the technical dependencies. But there are also complex governance and policy implications of these dependencies. Each organisation has membership rules, guidelines and governance structures which can impact Crossref members. Indeed, the IDF and CNRI are themselves members of groups (ISO and DONA, respectively) which might ultimately have policy or governance impact for DOI registration agencies. We will need to understand the strategic implications of these non technical dependencies as well.

Note that the Crossref board has merely asked us to “explore” what it would take to remove dependencies. They have not asked us to actually take any action. Crossref has been massively supportive of the IDF and CNRI, and they have been massively supportive of us. Still, over the years we have all grown and our respective circumstances have changed. It is important that occasionally we question what we might have once considered to be axioms. As we discussed above, we use the term “persistent” which, in turn, is a synonym for “stubborn.” At the very least we need to document the inter-dependencies that we have so that we can understand just how stubborn we can reasonably expect our identifiers to be.

The outage of January 20th was a humbling experience. But in a way we were lucky: Forgetting to renew the domain name was a silly and prosaic way to partially bring down a persistent identifier infrastructure, but it was also relatively easy to fix. Inevitably, there was a little snark and some pointed barbs directed at us during the outage, but we were truly overwhelmed by the support and constructive criticism we received as well. We have also been left with a clear message that, in order for this good-will to continue, we need to follow-up with a public, detailed and candid analysis of our infrastructure and its dependencies. Consider this to be the first section of a multi-part report.

@kevingashley tweets asking for followup analysis

@WilliamKilbride tweets asking for followup and lessons learned

Image Credits

Turtle image CC-BY “Unrecognised MJ” from the Noun Project

Problems with dx.doi.org on January 20th 2015- what we know.

Geoffrey Bilder — Wed, 21 Jan 2015 00:00:00 +0000

Hell’s teeth.

So today (January 20th, 2015) the DOI HTTP resolver at dx.doi.org started to fail intermittently around the world. The doi.org domain is managed by CNRI on behalf of the International DOI Foundation. This means that the problem affected all DOI registration agencies including Crossref, DataCite, mEDRA etc. This also means that more popularly known end-user services like FigShare and Zenodo were affected. The problem has been fixed, but the fix will take some time to propagate throughout the DNS system. You can monitor the progress here:

https://www.whatsmydns.net/#A/doi.org

Now for the embarrassing stuff…

At first lots of people were speculating that the problem had to do with somebody forgetting to renew the dx.doi.org domain name. Our information from CNRI was that the problem had to do with a mistaken change to a DNS record and that the domain name wasn’t the issue. We corrected people who were reporting that domain name renewal as the cause, but eventually we learned that it was actually true. We have had it confirmed that the problem originated with CNRI manually renewing the domain name at the last minute. Ugh. CNRI will issue a statement soon. We’ll link to it as soon as they do. UPDATE (Jan 21st): CNRI has sent Crossref a statement. They do not have it on their site yet, so we have can included it below.

In the mean time, if you are having trouble resolving DOIs, a neat trick to know is that you can do so using the Handle system directly. For example:

http://hdl.handle.net/10.5555/12345678

Crossref will, of course, also analyse what occurred, and issue a public report as well. Obviously, this report will include an analysis of how the outage effected DOI referrals to our members.

The amazingly cool thing is that everybody online has been very supportive and has helped us to diagnose the problem. Some have even said that the event underscores a point we often make about so-called “persistent-identifiers”- which is that they are not magic technology; the “persistence” is the result of a social contract. We like to say that Crossref DOIs are as persistent as Crossref staff. Well, to that phrase we have to add “and IDF staff” and “CNRI staff” and “ICANN staff”. It is turtles all the way down.

We don’t want to dismiss this event as an inevitable consequence of interdependent systems.And we don’t want to pass the buck. We need to learn something practical from this. How can we guard against this type of problem in the future? Again, people following this issue on Twitter have already been helping with suggestions and ideas. Can we crowd-source the monitoring of persistent identifier SLAs? Could we leverage Wikipedia, Wikidata or something similar to monitor critical identifiers and other infrastructure like purls, DOIs, handles, PMIDs, perma.cc, etc? Should we be looking at designating special exceptions to the normal rules governing DNS names? Do we need to distribute the risk more? Or is it enough cough to simply ensure that somebody, somewhere in the dependency chain had enabled DNS protection and auto-renewal for critical infrastructure DNS names?

Truly, we are humbled. For all the redundancy built into our systems (multiple servers, multiple hosting sites, Raid drives, redundant power), we were undone by a simple administrative task. Crossref, IDF and CNRI- we all feel a bit crap. But we’ll get back. We’ll fix things. And we’ll let you know how we do it.

We will update this space as we know more. We will also keep people updated on twitter on @CrossrefNews. And we will report back in detail as soon as we can.

CNRI Statement

"The doi.org domain name was inadvertently allowed to expire for a brief period this morning (Jan 20). It was reinstated shortly after 9am this morning as soon as the relevant CNRI employee learned of it. A reminder email sent earlier this month to renew the registration was apparently missed. We sincerely apologize for any difficulties this may have caused. The domain name has since been placed on automatic renewal, which should prevent any repeat of this event."

Linking data and publications

Geoffrey Bilder — Sun, 21 Sep 2014 00:00:00 +0000

Do you want to see if a Crossref DOI (typically assigned to publications) refers to DataCite DOIs (typically assigned to data)? Here you go:

https://web.archive.org/web/20150121025249/http://api.labs.crossref.org/graph/doi/10.4319/lo.1997.42.1.0001

Conversely, do you want to see if a DataCite DOI refers to Crossref DOIs? Voilà:

https://web.archive.org/web/20150321190744/http://api.labs.crossref.org/graph/doi/10.1594/pangaea.185321

Background

“How can we effectively integrate data into the scholarly record?” This is the question that has, for the past few years, generated an unprecedented amount of handwringing on the part researchers, librarians, funders and publishers. Indeed, this week I am in Amsterdam to attend the 4th RDA plenary in which this topic will no doubt again garner a lot of deserved attention.

We hope that the small example above will help push the RDAs agenda a little further. Like the recent ODIN project, It illustrates how we can simply combine two existing scholarly infrastructure systems to build important new functionality for integrating research objects into the scholarly literature.

Does it solve all of the problems associated with citing and referring to data? Can the various workgroups at RDA just cancel their data citation sessions and spend the week riding bikes and gorging on croquettes? Of course not. But my guess is that by simply integrating DataCite and Crossref in this way, we can make a giant push in the right direction.

There are certainly going to be differences between traditional citation and data citation. Some even claim that citing data isn’t “as simple as citing traditional literature.” But this is a caricature of traditional citation. If you believe this, go off an peruse the MLA, Chicago, Harvard, NLM and APA citation guides. Then read Anthony Grafton’s, The Footnote? Are you back yet? Good, so let’s continue…

Citation of any sort is a complex issue- full of subtleties, edge-cases exceptions, disciplinary variations and kludges. Historically, the way to deal with these edge-cases has been social, not technical. For traditional literature we have simply evolved and documented citation practices which generally make contextually-appropriate use of the same technical infrastructure (footnotes, endnotes, metadata, etc.). I suspect the same will be true in citing data. The solutions will not be technical, they will mostly be social. Researchers, and publishers will evolve new, contextually appropriate mechanisms to use existing infrastructure deal with the peculiarities of data citation.

Does this mean that we will never have to develop new systems to handle data citation? Possibly But I don’t think we’ll know what those systems are or how they should work until we’ve actually had researchers attempting to use and adapt the tools we have.

Technical background

About five years ago, Crossref and DataCite explored the possibility of exposing linkages between DataCite and Crossref DOIs. Accordingly, we spent some time trying to assemble an example corpus that would illustrate the power of interlinking these identifiers. We encountered a slight problem. We could hardly find any examples. At that time, virtually nobody cited data with DataCite DOIs and, if they did, the Crossref system did not handle them properly. We had to sit back and wait a while.

And now the situation has changed.

This demonstrator harvests DataCite DOIs using their OAI-PMH API and links them in a graph database with Crossref DOIs. We have exposed this functionality on the “labs” (i.e. experimental) version of our REST API as a graph resource. So…

Now you can get a list of Crossref DOIs that refer to DataCite DOIs using Event Data.

Caveats and Weasel Words

We have not finished indexing all the links.
The API is currently a very early labs project. It is about as reliable as a devolution promise from Westminster.
The API is run on a pair of raspberry-pi’s connected to the internet via bluetooth.
It is not fast.
The representation and the API is under active development.Things will change. Watch the Crossref Labs site for updates on this collaboration with DataCite

DOIs unambiguously and persistently identify published, trustworthy, citable online scholarly literature. Right?

Geoffrey Bilder — Fri, 20 Sep 2013 00:00:00 +0000

The South Park movie , “Bigger, Longer & Uncut” has a DOI:

a) http://dx.doi.org/10.5240/B1FA-0EEC-C316-3316-3A73-L

So does the pornographic movie, “Young Sex Crazed Nurses”:

b) http://dx.doi.org/10.5240/4CF3-57AB-2481-651D-D53D-Q

And the following DOI points to a fake article on a “Google-Based Alien Detector”:

c) http://dx.doi.org/10.6084/m9.figshare.93964

And the following DOI refers to an infamous fake article on literary theory:

d) http://dx.doi.org/10.2307/466856

This scholarly article discusses the entirely fictitious Australian “Drop Bear”:

e) http://dx.doi.org/10.1080/00049182.2012.731307

The following two DOIs point to the same article- the first DOI points to the final author version, and the second DOI points to the final published version:

f) https://web.archive.org/web/20160423204031/https://figshare.com/articles/Relating_ion_channel_expression,_bifurcation_structure,_and_diverse_firing_patterns_in_a_model_of_an_identified_motor_neuron/96546

g) http://dx.doi.org/10.1007/s10827-012-0416-6

This following two DOIs point to the same article- there is no apparent difference between the two copies:

h) http://dx.doi.org/10.6084/m9.figshare.91541

i) http://dx.doi.org/10.1038/npre.2012.7151.1

Another example where two DOIs point to the same article and there is no apparent difference between the two copies:

j) http://dx.doi.org/10.1364/AO.39.005477

k) http://dx.doi.org/10.3929/ethz-a-005707391

These journals assigned DOIs, but not through Crossref:

l) http://dx.doi.org/10.3233/BIR-2008-0496

m) https://web.archive.org/web/20160423192452/https://figshare.com/articles/Role_of_brain_glutamic_acid_metabolism_changes_in_neurodegenerative_pathologies/95564

n) http://dx.doi.org/10.3205/cto000081

These two DOIs are assigned to two different data sets by two different RAs:

o) http://dx.doi.org/10.1107/S0108767312019034/eo5016sup1.xls

p) http://dx.doi.org/10.1594/PANGAEA.726855

This DOI appears to have been published, but was not registered until well after it was published. There were 254 unsuccessful attempts to resolve it in September 2012 alone:

q) http://dx.doi.org/10.4233/uuid:995dd18a-dc5d-4a9a-b9eb-a16a07bfcc6d

The owner of prefix, ‘10.4223,’ who is responsible for the above DOI had 378,790 attempted resolutions in September 2012 of which there were 377,001 failures. The top 10 DOI failures for this prefix each garnered over 200 attempted resolutions. As of November 2012 the prefix had only registered 349 DOIs.

Of the above 16 example DOIs 11 cannot be used for CrossCheck or Crossmark. 3 cannot be used with content negotiation. To search metadata for the above examples, you need to visit four sites:

https://web.archive.org/web/20131229210637/http://search.crossref.org/

https://ui.eidr.org/search

https://www.medra.org/en/search.htm

https://search.datacite.org/

The 14 examples come from just 4 of the 8 existing DOI registration agencies (RAs) It is virtually impossible for somebody without specialized knowledge to tell which DOIs are Crossref DOIs and which ones are not.

Background

So DOIs unambiguously and persistently identify published, trustworthy, citable online scholarly literature. Right? Wrong.

The examples above are useful because they help elucidate some misconceptions about the DOI itself, the nature of the DOI registration agencies and, in particular issues being raised by new RAs and new DOI allocation models.

DOIs are just identifiers

Crossref’s dominance as the primary DOI registration agency makes it easy to assume Crossref’s particular application of the DOI as a scholarly citation identifier is somehow intrinsic to the DOI. The truth is, the DOI has nothing specifically to do with citation or scholarly publishing. It is simply an identifier that can be used for virtually any application. DOIs could be used as serial numbers on car parts, as supply-chain management identifiers for videos and music or as cataloguing numbers for museum artifacts. The first two identifiers listed in the examples (a & b) illustrate this. They both belong to MovieLabs and are part of the EIDR (Entertainment Identifier Registry) effort to create a unique identifier for television and movie assets. At the moment, the DOIs that MoveLabs are assigning are B2B-focused and users are unlikely to see them in the wild. But we should recall that Crossref’s application of DOIs was also initially considered a B2B identifier- but it has since become widely recognized and depended on by researchers, librarians and third parties. The visibility of EIDR DOIs could change rapidly as they become more popular.

Multiple DOIs can be assigned to the same object

There is no International DOI Foundation (IDF) prohibition against assigning multiple DOIs to the same object. At most the IDF suggests that RAs might coordinate to avoid duplicate assignments, but it provides no guidelines on how such cross-RA checks would work.

Crossref, in its particular application of the DOI, attempts to ensure that we don’t assign two different copies of the same article with different DOIs, but that is designed in order to avoid having publishers mistakenly making duplicate submissions. Even then, there are subtle exceptions to this rule- the same article, if legitimately published in two different issues (e.g. a regular issue and a thematic issue) will be assigned different DOIs. This is because, though the actual article content might be identical, the context in which it is cited is also important to record and distinguish. Finally, of course, we assign multiple DOIs to the same “object” when we assign book-level and chapter level DOIs. Or when we assign DOIs to components or reference work entries.

The likelihood of multiple DOIs being assigned to the same object increases as we have multiple RAs. In the future we might legitimately have a monograph that has different Bowker DOIs for different e-book platforms (Kindle, iPad, Kobo.) yet all three might share the same Crossref DOI for citation purposes.

Again, the examples show this already happening. The examples f & g are assigned by DataCite (via FigShare) and Crossref respectively. The first identifies the author version and was presumably assigned by said author. The second identifies the publisher version and was assigned by the publisher.

Although Crossref, as a publisher-focused RA, might have historically proscribed the assignment of Crossref DOIs to archive or author versions, there has never been and could never be any such restrictions on other DOI RAs. These are legitimate applications of two citation identifiers to two versions of the same article.

However, the next set of examples, h, i, j and k show what appears to be a slightly different problem. In these cases articles that appear to be in all aspects identical have been assigned two separate DOIs by different RAs. In one respect this is a logistical or technical problem- although Crossref can check for such potential duplicate assignments within its own system, there is no way for us to do this across different RAs. But this is also a marketing and education problem- how do RAs with similar constituencies (publishers, researchers, librarians) and application of the DOI (scholarly citation) educate and inform their members about best practice in applying DOIs in that particular RAs context?

DOI registration agencies are not focused on record types, they are focused on constituencies and applications

The examples f through k also illustrate another area of fuzzy thinking about RAs- that they are somehow built around particular record types. We routinely hear people mistakenly explain that difference between Crossref and DataCite is that “Crossref assigns DOIs to journal articles” and that “DataCite assigns DOIs to data.” Sometimes this is supplemented with “and Bowker assigns DOIs to books.” This is nonsense. Crossref assigns DOIs to data (example o) as well as conference proceedings, programs, images, tables, books, chapters, reference entries, etc. And DataCite covers a similar breadth of record types including articles (examples c, h, f, l, m ). The difference between Crossref, DataCite and Bowker is their constituencies and applications- not the record types they apply DOIs to. Crossref’s constituency is publishers. DataCite’s constituency is data repositories, archives and national libraries. But even though Crossref and DataCite have different constituencies, they share a similar application of the DOI- that is the use of DOI as citation identifiers. This is in contrast to MovieLabs whose application of the DOI is supply chain management.

DOI registration agency constituencies and applications can overlap or be entirely separate

Although Crossref’s constituency is “publishers”, we are catholic in our definition of “publisher” and have several members who run repositories that also “publish” content such as working papers and other grey literature (e.g. Woods Hole Oceanographic Institution, University of Michigan Library, University of Illinois Library). DataCite’s constituency is data repositories, archives and national libraries, but this doesn’t stop DataCite (through CDL/FigShare) from working with the publisher, PLoS, on their “Reproducibility Initiative” which requires the archiving of article-related datasets. PloS has announced that they will host all supplemental data sets on FigShare but will assign DOIs to those items through Crossref.

Crossref’s constituency of publishers overlaps heavily with Airiti, JaLC, mEDRA, ISTIC and Bowker. In the case of all but Bowker we also overlap in our application of the DOI in the service of citation identification. Bowker, though it shares Crossref’s constituency, uses DOIs for supply chain management applications.

Meanwhile, EIDR is an outlier, its constituency does not overlap with Crossref’s and its application of the DOI is different as well.

The relationship between RA constituency overlap (e.g. scholarly publishers vs television/movie studios) and application overlap (e.g. citation identification vs. supply chain management) can be visualized as such:

The differences (subtle or large) between the various RAs are not evident to anybody without a fairly sophisticated understanding of the identifier space and the constituencies represented by the various RAs. To the ordinary person these are all just DOIs, which in turn are described as simply being “persistent interoperable identifiers.”

Which of course begs the question, what do we mean by “persistent” and “interoperable?”

DOIs only are as persistent as the registration agency’s application warrants.

The word “persistent” does not mean “permanent.” Andrew Treloar is known to point out that the primary sense of the word “persistent” in the New Oxford American Dictionary is:

Continuing firmly or obstinately in a course of action in spite of difficulty or opposition

Yet presumably the IDF once chose to use the word “persistent” instead of “perpetual” or “permanent” for other reasons. “Persistence” implies longevity, without committing to “forever.”

It may sound prissy, but it seems reasonable to expect that the useful life-expectancy for the identifier used for managing inventory of the the movie “Young Sex Crazed Nurses” might be different than the life expectancy for the identifier used to cite Henry Oldenburg’s “Epistle Dedicatory” in the first issue of the Philosophical Transactions. In other words, some RAs have a mandate to be more “obstinate” than others and so their definitions of “persistence” may vary. Different RAs have different service level agreements.

The problem is that ordinary users of the “persistent” DOI have no way of distinguishing between those DOIs that are expected to have a useful life of 5 years and those DOIs that are expected to have a useful lifespan of 300+ years. Unfortunately, if one of the more than 6 million non-Crossref DOIs breaks today, it will likely be blamed on Crossref.

Similarly, if a DOI doesn’t work with an existing Crossref service, like CrossCheck, Crossmark or Crossref Metadata Search, it will also be laid at the foot of Crossref. This scenario is likely to become even more complex as different RAs provide different specialized services for their constituencies.

Ironically, the converse doesn’t always apply. Crossref oftentimes does not get credit for services that we instigated at the IDF level. For instance, FigShare has been widely praised for implementing content negotiation for DOIs even though this initiative had nothing to do with FigShare, instead it was implemented by DataCite with the prodding and active help of Crossref (DataCite even used Crossref’s code for a while). To be clear, we don’t begrudge praise for FigShare. We think FigShare is very cool- this just serves as an example of the confusion that is already occurring.

DOIs are only “interoperable” at a least common denominator level of functionality

There is no question that use of Crossref DOIs has enabled the interoperability of citations across scholarly publisher sites. The extra level of indirection built into the DOI means that publishers do not have to worry about negotiating multiple bilateral linking agreements and proprietary APIs. Furthermore, at the mundane technical level of following HTTP links, publishers also don’t have to worry about whether the DOI was registered with mEDRA, DataCite or Crossref as long as the DOI in question was applied with citation linking in mind.

However, what happens if somebody wants to use metadata to search for a particular DOI? What happens if they expect that DOI to work with content negotiation or to enable a CrossCheck analysis or show a Crossmark dialog or carry FundRef data? At this level, the purported interoperability of the DOI system falls apart. A publisher issuing DataCite DOIs cannot use CrossCheck. A user with a mEDRA DOI cannot use it with content negotiation. Somebody searching Crossref Metadata Search or using Crossref’s OpenURL API will not find DataCite records. Somebody depositing metadata in an RA other than Crossref or DataCite will not be able to deposit ORCIDs.

There are no easy or cheap technical solutions to fix this level of incompatibility baring the creation of a superset of all RA functionality at the IDF level. But even if we had a technical solution to this problem- it isn’t clear that such a high-level of interoperability is warranted across all RAs. The degree of interoperability that is desirable between RAs is only in proportion to the degree that they serve overlapping constituencies (e.g. publishers) or use the DOI for overlapping applications (e.g. citation)

DOI Interoperability matters more for some registration agencies than others

This raises the question of what it even means to be “interoperable” between different RAs that share virtually no overlap in constituencies or applications. In what meaningful sense do you make a DOI used for inventory control “interoperable” with a DOI used for identifying citable scholarly works? Do we want to be able to check “Young Sex Crazed Nurses” for plagiarism? Or let somebody know when the South Park movie has been retracted or updated? Do we need to alert somebody when their inventory of citations falls below a certain threshold? Or let them know how many copies of a PDF are left in the warehouse?

The opposite, but equally vexing issue arrises for RAs that actually share constituencies and/or applications. Crossref, DataCIte and mEDRA have all built separate metadata search capabilities, separate deposit APIs, separate OpenURL APIs, and separate stats packages- all geared at handling scholarly citation linking.

Finally, it seems a shame that a third party, like ORCID, who wants to enable researchers to add any DOI and its associated metadata to their ORCID profile, will end up having to interface with 4-5 different RAs.

Summary and closing thoughts

Crossref was founded by publishers who were prescient in understanding that, as scholarly content moved online, there was the potential to add great value to publications by directly linking citations to the documents cited. However, publishers also realized that many of the architectural attributes that made the WWW so successful (decentralization, simple protocols for markup, linking and display, etc.), also made the web a fragile platform for persistent citation.

The Crossref solution to this dilemma was to introduce the use of the DOI identifier as a level of citation indirection in order to layer a persist-able citation infrastructure onto the web. The success of this mechanism has been evident at a number of levels. A first-order effect of the system is that it has allowed publishers to create reliable and persistent links between copies of publisher content. Indeed uptake of the Crossref system by scholarly and professional publishers has been rapid and almost all serious scholarly publishers are now Crossref members.

The second order effects of the Crossref system have also been remarkable. Firstly, just as researchers have long expected that any serious paper-based publication would include citations, now researchers expect that serious online scholarly publications will also support robust online citation linking. Secondly, some have adopted a cargo-cult practice of seeing the mere presence of a DOI on a publication as a putative sign of “citability” or “authority.” Thirdly, interest in use of the DOI as a linking mechanism has started to filter out to researchers themselves, thus potentially extending the use of Crossref DOIs beyond being primarily a B2B citation convention.

The irony is that although the DOI system was almost single-handedly popularized and promoted by Crossref, the DOI brand is better known than Crossref itself. We now find that new RAs like EIDR, DataCite and new services like FigShare are building on the DOI brand and taking it in new directions. As such the first and second order benefits of Crossref’s pioneering work with DOIs are likely to be effected by the increasing activity of the new DOI RAs as well as the introduction of new models for assigning and maintaining DOIs.

How can you trust that a DOI is persistent if different RAs have different conceptions of persistence? How can you expect the presence of a DOI to indicate “authority” or “scholarliness” if DOIs are being assigned to porn movies? How can you expect a DOI to point to the “published” version of an article when authors can upload and assign DOIs to their own copies of articles?

It is precisely because we think that some of the qualities traditionally (and wrongly) accorded to DOIs (e.g. scholarly, published, stewarded, citable, persistent) are going to be diluted in the long term that we have focused so much of our recent attention on new initiatives that have a more direct and unambiguous connection to assessing the trustworthiness of Crossref member’s content. CrossCheck and the CrossCheck logos are designed to highlight the role that publishers play in detecting and preventing academic fraud. The Crossmark identification service will serve as a signal to researchers that publishers are committed to maintaining their scholarly content as well as giving scholars the information they need to verify that they are using the most recent and reliable versions of a document. FundRef is designed to make the funding sources for research and articles transparent and easily accessible. And finally we have been both adjusting Crossref’s branding and display guidelines as well as working with the IDF to refine its branding and display guidelines so as to help clearly differentiate different DOI applications and constituencies.

Whilst it might be worrying to some that DOIs are being applied in ways that Crossref has not expected and may not have historically endorsed, we should celebrate that the broader scholarly community is finally recognizing the importance of persist-able citation identifiers.

These developments also serve to reinforce a strong trend that we have encountered in several guises before. That is, the complete scholarly citation record is made up of more than citations to the formally published literature. Our work on ORCID underscored that researchers, funding agencies, institutions and publishers are interested in developing a more holistic view of the manifold contributions that are integral to research. The “C” in ORCID stands for “contributor” and ORCID profiles are designed to ultimately allow researchers to record “products” which include not only formal publications, but also data sets, patents, software, web pages and other research outputs. Similarly, Crossref’s analysis of the Cited-by references revealed that one in fifteen references in the scholarly literature published in 2012 included a plain, ordinary HTTP URI- clear evidence that researchers need to be able to cite informally published content on the web. If the trend in Cited-by data continues, then in two to three years one in ten citations will be of informally published literature.

The developments that we are seeing are a response to the need that users have to persistently identify and cite the full gamut of record types that make up the scholarly literature. If we can not persistently site these record types, the scholarly citation record will grow increasingly porous and structurally unsound. We can either stand back and let these gaps be filled by other players under their terms and deal reactively with the confusion that is likely to ensue- or we can start working in these areas too and help to make sure that what gets developed interacts with the existing online scholarly citation record in a responsible way.

Crossref and DataCite unify support for HTTP content negotiation

Crossref — Thu, 17 May 2012 00:00:00 +0000

Last year Crossref and DataCite announced support for HTTP content negotiation for DOI names. Today, we are pleased to report further collaboration on the topic. We think it is very important that the two largest DOI Registration Agencies work together in order to provide metadata services to DOI names.

The current implementation is documented in detail at http://citation.crosscite.org/

The documentation explains HTTP content negotiation as implemented by both Registration Agencies and provides a list of supported resource/content/record types.

An example application of HTTP content negotiation is a citation formatting service. You can try it at http://citation.crosscite.org/.

This service will accept DOIs from both Crossref and DataCite, unlike the previous formatting service which accepted only Crossref DOI names.

This is possible because Crossref and DataCite support a shared, common metadata format. When you input a DOI into the formatting service, it doesn’t know where the DOI was registered. The service will make an

HTTP content negotiation request to the global DOI resolver specifying which format of the metadata should be returned in the HTTP Accept header. The global DOI resolver will notice (Accept header!) that this is not a regular DOI resolution request; it will turn to Crossref or DataCite accordingly for the relevant metadata instead of redirecting to a landing page. The format of metadata is shared between both registration agencies so the formatting service can interpret it without knowledge of the DOI origin.

In summary HTTP content negotiation lets you process a DOI’s metadata without knowledge of its origin or specifics of the registration agency.

If you have any problems, email us at tech@datacite.org or labs@crossref.org. For general discussion please kindly leave a comment below.

DataCite supporting content negotiation

Geoffrey Bilder — Mon, 10 Oct 2011 00:00:00 +0000

In April In April for its DOIs. At the time I cheekily called-out DataCite to start supporting content negotiation as well.

Edward Zukowski (DataCite’s resident propellor-head) took up the challenge with gusto and, as of September 22nd DataCite has also been supporting content negotiation for its DOIs. This means that one million more DOIs are now linked-data friendly. Congratulations to Ed and the rest of the team at DataCite.

We hope this is a trend. Back in June Knowledge Exchange organized a seminar on Persistent Object Identifiers. One of the outcomes of the meeting was “Den Haag Manifesto” a document outlining five relatively simple steps that different persistent identifier systems could take in order to increase interoperability. Most of these steps involved adopting linked data principles including support for content negotiation. We look forward to hearing about other persistent identifiers adopting these principles over the next year.

Having said that, this time I will refrain from calling-out anybody specifically…

Content Negotiation for Crossref DOIs

Geoffrey Bilder — Tue, 19 Apr 2011 00:00:00 +0000

So does anybody remember the posting DOIs and Linked Data: Some Concrete Proposals?

Well, we went with option “D.”

From now on, DOIs, expressed as HTTP URIs, can be used with content-negotiation.

Let’s get straight to the point. If you have curl installed, you can start playing with content-negotiation and Crossref DOIs right away:

curl -D - -L -H   “Accept: application/rdf+xml” “http://dx.doi.org/10.1126/science.1157784”

curl -D - -L -H   “Accept: text/turtle” “http://dx.doi.org/10.1126/science.1157784”

curl -D - -L -H   “Accept: application/atom+xml” “http://dx.doi.org/10.1126/science.1157784”

Or if you are already using Crossref’s “unixref” format:

curl -D - -L -H “Accept: application/unixref+xml” “http://dx.doi.org/10.1126/science.1157784&#8221;

This will work with over 46 million Crossref DOIs as of today, but the beauty of the setup is that from now on, any DOI registration agency can enable content negotiation for their constituencies as well. DataCite- we’re looking at you 😉 .

It also means that, as registration agency members (Crossref publishers, for instance) start providing more complete and richer representations of their content, we can simply redirect content-negotiated requests directly to them.

We expect that that this development will round-out Crossref’s efforts to support standard APIs including OpenURL and OAI_PMH and we look forward to seeing DOIs increasingly used in linked data applications.

Finally, Crossref would just like to thank the IDF and CNRI for their hard work on this as well as Tony Hammond and Leigh Dodds for their valuable advice and persistent goading.