More PIDs

First of all, what is a PID?

A Persistent Identifier (PID) is a unique, long-lasting reference in the form of a string or code that identifies digital objects, researchers, or organizations, ensuring their retrievability and referenceability over the long term. PIDs are primarily used for digital resources and provide resolvable, persistent links. However, some widely used identifiers, like ISBNs and ISSNs, also serve as standardized unique references for both physical and digital resources. Unlike PIDs, ISBNs and ISSNs do not automatically resolve to a resource.

Here are some common PIDs in addition to DOIs:

  • ARK (Archival Resource Key) – Used for persistent access to digital and physical objects, especially in libraries and archives.
    Example: ARK for a digital archive – ark:/12148/cb375723390
  • URN (Uniform Resource Name) – A persistent, location-independent identifier, which means it is used to uniquely identify a resource by name, rather than location. Often used in library and government systems. While URNs themselves do not resolve to a resource directly, they can be paired with resolution services.
    Example: URN for a document – urn:nbn:de:bsz:21-opus-49771. URNs are part of the larger Uniform Resource Identifier (URI) system, which also includes URLs.
  • RRID (Research Resource Identifier) – Used to identify and cite research materials such as antibodies, cell lines, model organisms, software and databases to improve reproducibility in science. RRIDs are also used for core facilities to ensure proper acknowledgment.
    Example: Max Planck Institute of Molecular Cell Biology and Genetics Light Microscopy Core Facility RRID:SCR_023307
  • RAiD (Research Activity Identifier) – RAiDs track entire research activities and are containers for PIDs describing the components of a project such as researchers, datasets, funding/grants, institutions, and outputs. RAiDs are based on the handle-system. Example: RAiD: 10378.1/RAiD.987654 (Hypothetical Example)
    Resolves via: https://raid.org.au/view/10378.1/RAiD.987654

By assigning unique and stable identifiers, PIDs and related identifiers help prevent broken links, ensure proper citation, and facilitate long-term access to scholarly and published resources.

Which other PIDs are used at MPDL?

  • Handle – A handle is another unique identifier that provides a permanent and stable link to a digital object. Handles are part of the Handle System, which ensures long-term accessibility. A well-known example of a handle is the DOI. At MPDL, handles are used in MPG.PuRe(the Max Planck Society’s publication repository). Example: https://hdl.handle.net/21.11116/0000-0009-77C1-7
  • ROR ID (Research Organization Registry Identifier) – ROR IDs are unique identifiers for research organizations worldwide. The Research Organization Registry is an open, community-driven registry designed to uniquely identify institutions such as universities, research centers, and other academic organizations. The Max Planck Society and its institutes are associated with 142 active ROR IDs. You can find them here. ROR IDs are used in our open research data repository Edmond to link researchers to their correct affiliation. Example: Max Plank Society – https://ror.org/01hhn8329
  • ORCID (Open Researcher and Contributor ID) – An ORCID is a unique identifier for researchers and authors. It helps distinguish individuals with similar names and ensures proper attribution of their work. MPG.PuRe and Edmond encourage researchers to include their ORCIDs when publishing via these platforms. Example: ORCID for a researcher – 0000-0002-1825-0097