Persistent identifiers

[Source:  D2.2 State of the art report on persistent identifier standards and management tools (PDF, 1093kb)]


For the creation of digital identifiers, for the entities they intend to manage, institutions should:

Make use of the Uniform Resource Identifier (URI) for this purpose, and should ensure that
the URI is reasonably persistent.


The following are a set of institutional requirements which need to be considered when starting to use
PIDs. Institutions should:

  • Be clear, and make public, in which environments its PIDs are unique;
  • Commit themselves to the persistence of their PIDs. They should make it clear to
    others what they mean by ‘persistent’, and how this will be implemented;
  • Be clear, and make public, information about which, if any, their PIDs resolve to an
    available resource;
  • Use PID systems that are free of charge or at very low cost in relationship to their
    available resources;
  • Make sure that the uses of PIDs are part of the written policy of the institution;
  • Make sure that the management of an institution’s PID system is part of the written
    processes and procedures of the institution.


If an institution is considering using a PID service it should:

  • Evaluate and be assured of the technical reliability of a PID system (including theirown) before adopting it;
  • Evaluate and be assured of the authority and credibility of a PIDs service’s provider before adopting that system;
  • Make sure that the service it uses is flexible enough to represent the granularity their collections;
  • Make sure that the service uses intellectually open standards for the implementation of PIDs.


Based on Berners-Lee’s four principles of linked data institutions should:

Use persistent identifiers for things in the form of persistent URIs, which provide information to the user.

When creating URIs, from non-URI identifiers, institutions should:

Use the URI creation patterns and techniques given by Dodds and Davis (Dodds, Leigh and Davis, Ian. Linked Data Patterns: A pattern catalogue for modelling, publishing, and consuming Linked Data.
2012. pp4-11. Accessible from:

Title: State of the art report on persistent identifier standards and management tools

  • Hierarchical URIs;
  • Natural Keys;
  • Patterned URIs;
  • Literal Keys;
  • Proxy URIs;
  • URL Slug;
  • Rebased URI;
  • Shared Keys

to create a linked data system.

When implementing URIs institution should use:

  • Hash URIs – for rather small and stable sets of resources that evolve together;
  • 303 URIs – where a publisher wants to have the flexibility of being able to deliver data about single items, groups of items, or all the items in repository. Using this method has the downside of slower response times.

It is possible to combine both approaches to come up with the best solution under particular circumstances.


An institution’s mission statement:

An institution’s mission statement should include elements on audience, activities, sustainability, and quality that give a general environment for the implementation and management of persistent identifiers.