EZID is a service and a platform provided by the California Digital Library for creating, registering, and managing persistent identifiers for scholarly research and cultural heritage objects, including but not limited to articles, datasets, images, and specimens.
Persistent identifiers are the backbone of scholarly communication infrastructure. As more knowledge circulates online, persistent identifiers are increasingly needed to help to disambiguate scholarly objects, to make these objects discoverable, shareable, and citable by both humans and machines, and to support long-term preservation and access. Persistent identifiers facilitate networked research environments, enable more robust measurement of scholarly outputs, and confer scholarly credibility.
EZID is a crucial piece of infrastructure that provides a streamlined, low-cost, and high-quality persistent identifier service for libraries, museums, research groups, and publishers.
EZID currently supports two types of commonly used identifiers: Digital Object Identifier (DOI) and Archival Resource Key (ARK). DOI services are available for University of California users only.
EZID offers a user interface and robust API and supports automated workflows standards-based processes.
"The partnership between EZID and Crossref presents an exciting opportunity for eScholarship and our journal partners. The inclusion of our Open Access publications in new discovery services via Crossref, particularly its metadata feed, will dramatically increase the exposure of the important scholarship published on our platform."
University of California libraries sponsor free EZID memberships for their campuses. Contact your librarian to request an account for your department or group.
|Assoc/Bac Granting Institution*||$300|
|Masters Granting Institution*||$600|
|Research Institution or Non-Profit Organization*||$1,500|
|Research group, department, or team||$500|
|Small (less than 100 employees)||$1,500|
|Medium (100 to 500 employees)||contact us|
|Large (over 500 employees)||contact us|
* Consortium (3 or more institutions or organizations) 20% discount on any fee marked
For any questions regarding the above categories or rates, please contact us.
University of California researchers: please contact us for UC rates.
An identifier is an association between a character string and an object. Objects can be files, parts of files, names of persons or organizations, abstractions, etc. Objects can be online or offline. Character strings include URLs, serial numbers, names, addresses, etc. A "persistent identifier" is an identifier that is available and managed over time; it will not change if the item is moved or renamed. This means that an item can be reliably referenced for future access by humans and software. EZID currently supports persistence for two kinds of identifiers: DataCite Digital Object Identifiers (DOIs) and lower-cost Archival Resource Keys (ARKs).
DOI stands for "Digital Object Identifier." It is an identifier originating from the publishing world and in widespread use for journal articles. DOIs become persistent when the objects and identifier forwarding information are maintained.
ARK stands for "Archival Resource Key." It is an identifier originating from the library, archive and museum community. ARKs become persistent when the objects and identifier forwarding information are maintained.
ARK identifiers have certain features that can be very useful for:
This can make it attractive to use ARKs during the early part of a dataset's "life" or the early stages of the research process. Then, when the time comes to begin writing up results and it becomes clear which object(s) will be cited, it may appropriate to get DOIs for those objects.
DOIs have the citation-level "reputation" and it is possible to use the ARK of the cited object as the "suffix" for the DOI so that there is a traceable connection between the two. Here is what that means:
Step 1. You assign an ARK to a resource for good management and tracking: ark:/99999/fk4sf2w65j
Step 2. You decide to cite the resource, so you want a DOI.
Step 3. Using either the Advanced Create UI or the API, request a doi with this form: doi:10.5072/FK2fk4sf2w65j
In this way, the two identifiers have a relationship, so the object can be tracked throughout its life cycle. With EZID, clients get access to both of these identifiers and can take best advantage of both approaches.
Instead of leading directly to an object, one identifier frequently points to another, or "target URL", that leads directly to the object. The process of getting to the final target name, possibly via a chain of intermediate names, is called "resolution." Resolution on the web is usually fast and invisible. It is done behind the scenes on your behalf by web browsers. Unsuccessful resolution, however, usually means visible failure to access the object that you were expecting, resulting in a "broken identifier." Objects tend to move, so identifier persistence depends on resolution using up-to-date target URLs. To make this happen, EZID provides a way for people to update target URLs as they change when objects move around. This is very similar to leaving a forwarding address when you change your residence. As the starting point for resolution, the resolver effectively lets you publicize an unchanging identifier that you maintain so that it will consistently hit a target that may be moving. EZID currently updates two resolvers: N2T (Name-to-Thing) based at n2t.net and the DOI (Digital Object Identifier) resolver based at doi.dx.org.
Metadata is information (data) about the object, such as the name of the object's creator, the date of creation, the target URL, the version of the object, its title, and so on. EZID allows the user to enter metadata at the same time as an identifier is requested. Associating metadata with identifiers enables more sophisticated mechanisms for digital content discovery and higher-level assurances of long-term persistence.
For information about the status of the EZID system, please consider the following options:
EZID identifiers can be related to external links if you associate them with metadata, for example by using the relatedIdentifier field in the DataCite metadata schema.
If you would like to include clickable links to DOIs and ARKs on a landing page, we recommend that you format them following this html template:
DOI: <a href="https://doi.org/10.1234/ABCD">doi:10.1234/ABCD</a>
ARK: <a href="http://n2t.net/ark:/12345/abcde">ark:/12345/abcde</a>
Because EZID has an API, it is possible to write code to interact with your Dspace repository.
If an account-holder leaves your institution, please let us know so that we revoke their CREATE access to EZID. They will continue to be able to maintain all existing identifiers.
If there is a researcher from your institution associated with the project, and if you want to sponsor the access, then we are okay with extending access. Please use the sponsored account order form (see above) to request the new account.
EZID and N2T at CDL Presentation at UC DLFx, February 27, 2018
Four Unsolved Problems (with Persistent Identifiers) Presentation at PIDapalooza, Palau de Congressos de Girona, Spain, January 23, 2018
Compact Identifiers for Data Citation in Biomedicine and Beyond Presentation at PIDapalooza, Palau de Congressos de Girona, Spain, January 23, 2018
Software Citation Principles Presentation at DataCite Strategy Meeting (slides), April 3, 2017
Identifiers and Citation: Frequently Asked Questions Presentation at California Data Librarians conference (slides), March 14, 2017