Persistent Digital Identifiers

A persistent digital identifier (PID) is a stable, scheme-governed string used to identify a research-related entity over time. Unlike an ordinary web address, it identifies the entity independently of its current location and is typically linked to maintained metadata through a registry or resolver. The entity may be digital, such as a dataset, or non-digital, such as a researcher or organisation.

How it works

A governed PID scheme assigns an identifier and associates it with a metadata record. A resolution service uses the identifier to retrieve that record or direct the user to the entity's current online location.

• The identifier remains unchanged when the entity's web address or descriptive metadata changes.
• The registry or responsible organisation updates the metadata or destination rather than issuing a new identifier.
• Persistence depends on continuing governance, technical maintenance and accurate metadata; it is not an inherent property of the character string.

Common identifiers in research

Different PID schemes identify different entities within the research system.

• A Digital Object Identifier (DOI) commonly identifies research outputs such as articles, datasets and reports.
• An ORCID iD distinguishes an individual researcher from others with similar names or changing affiliations.
• A Research Organization Registry (ROR) ID identifies a research organisation.

Value for research information systems

PIDs allow databases to connect records about researchers, organisations, grants and outputs into a machine-readable network.

• They reduce ambiguity, duplication and errors caused by name variations or institutional changes.
• They improve discovery, attribution, interoperability and aggregation across repositories, publishers and administrative systems.
• They support more reliable analysis of research funding and outputs, but do not by themselves establish research quality, ownership or long-term preservation.