Persistent identifiers
A persistent identifier, or PID, is a unique ID number or a unique string of characters that remains stable over time. Persistent identifiers are used to identify objects, people, and organizations. There are different types of persistent identifiers depending on what they identify, and which organization issues them.
On this page you will find information about the following persistent identifiers:
These four types of PIDs are used in digital contexts where the PID functions as a unique and permanent reference that enables the discovery and reuse of digital material. PIDs are used to reference digital objects such as web pages, documents, or other files, but researchers and research organizations can also have a PID. A PID is similar to a hyperlink, but unlike most web links, a PID is maintained by an organization that ensures it always points to the same resource (e.g., a webpage, document, or file), even if that resource is moved in the future.
In addition to pointing to a resource, a PID is typically associated with metadata, such as a persistent description of the linked objects. Since PIDs exist online, they can be discovered and read by both humans and machines.
DOI
DOIOpens in a new tab is a commonly used persistent identifier for research data. The reason for assigning DOIs to research data is, among other things, to ensure that you can uniquely cite a certain version of a dataset. Citations also mean that you as a researcher can get recognition when data from your research is reused. Many scientific journals require that research data are accessible and have a PID, for example a DOI, in order to publish articles or studies based on those data.
The DOI links back to a persistent description of the dataset that does not change regardless of whether the data files are moved to other data repositories or archives. Even if the dataset is de-published, information about it can still be found through the DOI. The DOI will always be discoverable through doi.orgOpens in a new tab.
Example of a DOI: https://doi.org/10.5878/002353Opens in a new tab
This DOI points to Swedish version of the dataset ”The National SOM Survey 1995”, version 1.0. If the SOM Institute decides to create and publish a new version of this dataset, the new version will receive a new DOI. Even if the previous version of the dataset has already been used in analyses and publications, there is less risk of misunderstanding as it is possible to reference both versions in a consistent manner.
Pre-registering a DOI
Publishers and journals often request the DOI for a dataset associated with a manuscript or article that is being submitted. To accommodate this, many data repositories offer the possibility to pre-register a DOI. A pre-registered DOI is not activated until the dataset is publicly published. Researchers often publish the dataset so that the DOI is activated when the research article is accepted. The publisher then verifies that the data are accessible before approving the final version of the manuscript. However, some journals, particularly data journals, do not accept a pre-registered DOI and require that the dataset is published before the article is accepted for review.
ePIC
ePICOpens in a new tab (Persistent Identifier Consortium for eResearch) is a PID primarily used to provide identifiers for research data in the early stages of the research process. It is particularly useful when research generates large volumes of data or data files, and it is unclear which parts of the dataset will be cited in the future. Unlike a DOI, an ePIC does not require a persistent description of the data to be created.
Example of an ePIC PID: https://hdl.handle.net/21.T11998/0000-001D-B170-AOpens in a new tab
This specific ePIC is a demonstration PID that points to this information page.
ORCID
As a researcher you have every reason to create, maintain, and use an ORCIDOpens in a new tab (Open Researcher and Contributor ID). ORCID is a PID that persistently identifies you as an author. This ensures that research data, publications, and other scholarly works you have contributed to are uniquely linked to you.
Since ORCID is a persistent identifier, it continues to reference you even if you share a name with another researcher or if you change your name or institutional affiliation. Through your ORCID profile, you can also link to a comprehensive list of your publications and academic achievements that updates automatically.
Many research funders and journals require researchers to have an ORCID when submitting grant applications or manuscripts.
Example of an ORCID: https://orcid.org/0000-0002-1825-0097Opens in a new tab
This ORCID points to a fictitious researcher, Josiah Carberry. In his ORCID post (created for demonstrative purposes), you can see Josiah’s organizational affiliations and some of his publications. There are a couple of variations of Josiah’s name, which can help to ascertain whether he is the correct contributor in a certain context. Additionally, there is a connection to Josiah’s author ID in another system (Scopus Author ID). If Josiah Carberry had been a real researcher, he could, with the help of various metadata services, have kept the ORCID post up to date with new and current information.
ROR ID
Research Organization Registry (ROROpens in a new tab) provides ROR ID, a persistent identifier that uniquely points to a specific research organization, just as how ORCID points to a specific individual. ROR ID contains useful metadata for the organization and references other identifiers and related organizations.
A ROR ID can be used to uniquely identify and link to a research organization in, for example, a publication or grant application.
Example of a ROR ID: https://ror.org/00ancw882Opens in a new tab
This ROR ID identifies Swedish National Data Service. It is usually the English name of a research organization that is their primary entry in the ROR directory. Other names and abbreviations are mentioned in the entry in the ROR registry.