v2026.1CASRAI Dictionary 714 entries across 20 domains · CC-BY 4.0714 entries · CC-BY 4.0

Dictionary termTrack BStablev2026.2

PID graph

A graph data structure in which persistent identifiers (ORCID iDs, DOIs, ROR IDs, RAiDs, IGSNs, etc.) are nodes and the metadata relationships among them (creator-of, affiliated-with, funded-by, derived-from) are edges, allowing federated queries across multiple PID-provider registries.

ByCASRAI Editorial Board

· Last updated 21 May 2026

Examples

Worked examples

Is an instance
A query joining a Crossref DOI's authors via their ORCID iDs to their ROR-identified affiliations to their funded grants.
Is an instance
DataCite Commons displaying linked people / works / organisations / funders for a single DOI.

Counter-examples

Looks similar, but isn't

Not an instance
A standalone bibliography database with only internal IDs is not a PID graph.
Not an instance
A relational table inside a single CRIS is not a PID graph.

Editorial commentary

The PID graph concept was promoted by DataCite, Crossref, and ORCID through the FREYA project (2017-2020) and is operationalised in services such as DataCite Commons, OpenAIRE Graph, and the OpenAlex aggregator. Each PID registry contributes edges based on the metadata it holds; the union forms a graph that supports queries such as ‘all outputs from authors affiliated with ROR X funded by funder Y’ that no single registry could answer alone.

References

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Also known as

Research graph · PID network

Machine-readable encodings

Use in your systems

JATS XML <role> element

xml

<role vocab="credit"
      vocab-identifier="https://casrai.org/dictionary/"
      vocab-term="PID graph"
      vocab-term-identifier="https://casrai.org/dictionary/term/pid-graph" />

Schema.org DefinedTerm (JSON-LD)

json

{
  "@context": "https://schema.org",
  "@type": "DefinedTerm",
  "name": "PID graph",
  "identifier": "https://casrai.org/dictionary/term/pid-graph",
  "description": "A graph data structure in which persistent identifiers (ORCID iDs, DOIs, ROR IDs, RAiDs, IGSNs, etc.) are nodes and the metadata relationships among them (creator-of, affiliated-with, funded-by, derived-from) are edges, allowing federated queries across multiple PID-provider registries.",
  "inDefinedTermSet": "https://casrai.org/dictionary/domain/the-persistent-identifier-ecosystem/",
  "url": "https://casrai.org/dictionary/term/pid-graph",
  "sameAs": [
    "Research graph",
    "PID network"
  ],
  "license": "https://creativecommons.org/licenses/by/4.0/"
}

Adopted by research universities worldwide

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