Examples
Worked examples
- Is an instance
A ROR record listing the equivalent GRID ID, ISNI, and Crossref Funder ID for the same university.
- Is an instance
An ORCID record listing a Scopus Author ID under external identifiers.
Counter-examples
Looks similar, but isn't
- Not an instance
A free-text 'see also' note on a webpage is not an identifier crosswalk.
- Not an instance
A search engine's auto-completion suggestion is not a crosswalk.
- Not an instance
A federated multi-provider graph of many linked identifiers (see PID graph) is a larger structure built from many crosswalks, not itself a single crosswalk.
Editorial commentary
Identifier crosswalks are the practical mechanism by which heterogeneous PID systems can be queried jointly. ROR records carry crosswalks to GRID, ISNI, Wikidata, Crossref Funder ID, and Fundref. ORCID records carry external-identifier blocks for Scopus Author IDs, Researcher IDs, and other identifiers. DataCite Commons and the PID graph rely on crosswalks to traverse from a DOI to its authors’ ORCID iDs to their ROR-identified affiliations. Crosswalks may be 1:1, 1:N (one entity has multiple historical identifiers), or N:1 (multiple identifiers in one scheme map to a single entity in another).
Common crosswalk directions in practice
The most-used crosswalks in research infrastructure connect: organisation identifiers (ROR ↔ GRID ↔ ISNI ↔ Wikidata QID), person identifiers (ORCID ↔ Scopus Author ID ↔ ResearcherID), and funder identifiers (Crossref Funder ID ↔ national funder codes). GRID itself was deprecated by Digital Science in 2022 in favour of ROR, which is why current ROR records still carry a GRID-crosswalk field — it exists specifically so systems built against the older GRID identifiers keep working during the transition.
How this differs from a PID graph
A crosswalk is a single mapping relationship — typically expressed as one field or one row asserting “this identifier in scheme A equals that identifier in scheme B.” A PID graph is the larger structure that results from combining many crosswalks and many other relationship types (creator-of, funded-by, affiliated-with) across multiple registries into one queryable network. Read this entry for what an individual crosswalk mapping is; read the PID graph entry for the aggregate structure and the services (DataCite Commons, OpenAIRE Graph) built on top of it.
References
- ROR, ‘ROR Data Schema and Crosswalks’ (ror.org).
- DataCite, ‘DataCite Commons’ (commons.datacite.org).
Also known as
PID mapping · Identifier mapping
Machine-readable encodings
Use in your systems
<role vocab="credit"
vocab-identifier="https://casrai.org/dictionary/"
vocab-term="Identifier crosswalk"
vocab-term-identifier="https://casrai.org/dictionary/term/identifier-crosswalk" />{
"@context": "https://schema.org",
"@type": "DefinedTerm",
"@id": "https://casrai.org/dictionary/term/identifier-crosswalk",
"name": "Identifier crosswalk",
"identifier": "https://casrai.org/dictionary/term/identifier-crosswalk",
"description": "A mapping or correspondence table between identifiers in different schemes that refer to the same real-world entity, allowing a system holding one scheme's identifier to find the equivalent identifier in another scheme.",
"inDefinedTermSet": "https://casrai.org/dictionary/domain/persistent-identifiers#set",
"url": "https://casrai.org/dictionary/term/identifier-crosswalk",
"sameAs": [
"PID mapping",
"Identifier mapping"
],
"license": "https://creativecommons.org/licenses/by/4.0/",
"publisher": {
"@id": "https://casrai.org/#organization"
},
"author": {
"@id": "https://casrai.org/#editorial-team"
},
"datePublished": "2026-05-21T02:13:00",
"dateModified": "2026-08-22T15:38:13",
"inLanguage": "en-GB",
"isAccessibleForFree": true
}
