Wikidata Properties That Feed the Knowledge Graph
Session 5.4 · ~5 min read
In the previous session, you created a Wikidata item with core properties: type, website, location, founding date. Those properties establish what your entity is. This session covers the properties that connect your entity to other databases and authority systems. These are external identifiers, and they are disproportionately valuable for Knowledge Graph construction.
What External Identifiers Do
An external identifier is a Wikidata property that stores your entity's ID in another database. When Wikidata says your entity has ISNI number 0000 0004 1234 5678, it creates a machine-readable link between your Wikidata item and the ISNI database. Google can follow that link to cross-reference your entity across multiple authoritative sources.
This cross-referencing is how Google builds confidence. If your entity appears in Wikidata, the ISNI registry, the VIAF authority file, a government business registry, and your own website with matching schema markup, Google has five independent confirmations that your entity exists and has specific attributes. Each additional cross-reference increases entity confidence.
(Q????????)"] --> B["ISNI
(P213)"] A --> C["VIAF
(P214)"] A --> D["LinkedIn
(P6634/P4264)"] A --> E["Twitter/X
(P2002)"] A --> F["GND
(P227)"] A --> G["GRID
(P2427)"] A --> H["LEI
(P1278)"] B --> I["Google Knowledge
Graph: Cross-Reference
Confirmation"] C --> I D --> I E --> I F --> I G --> I H --> I style A fill:#222221,stroke:#c8a882,color:#ede9e3 style B fill:#222221,stroke:#6b8f71,color:#ede9e3 style C fill:#222221,stroke:#6b8f71,color:#ede9e3 style D fill:#222221,stroke:#8a8478,color:#ede9e3 style E fill:#222221,stroke:#8a8478,color:#ede9e3 style F fill:#222221,stroke:#6b8f71,color:#ede9e3 style G fill:#222221,stroke:#6b8f71,color:#ede9e3 style H fill:#222221,stroke:#6b8f71,color:#ede9e3 style I fill:#222221,stroke:#c8a882,color:#ede9e3
High-Impact External Identifiers
The following table maps the most valuable external identifiers, their impact on entity recognition, and how to obtain them. Not all are applicable to every entity type. Focus on the ones relevant to your entity.
| Identifier | Property ID | Applicable To | How to Obtain | KG Impact |
|---|---|---|---|---|
| ISNI (International Standard Name Identifier) | P213 | Persons, Organizations | Apply at isni.org. Requires published works or institutional presence. | Very High: used by Google for entity disambiguation |
| VIAF (Virtual International Authority File) | P214 | Persons, Organizations | Assigned automatically when a national library catalogs your work. Can also be requested. | Very High: aggregates library authority records globally |
| GND (Integrated Authority File) | P227 | Persons, Organizations | Assigned by German National Library. Useful for entities with European academic or publishing presence. | High: widely used authority file |
| LinkedIn Company ID | P4264 | Organizations | Found in your LinkedIn company page URL. | Medium: social-professional cross-reference |
| LinkedIn Personal Profile ID | P6634 | Persons | Found in your LinkedIn personal profile URL slug. | Medium: professional identity link |
| Twitter/X Username | P2002 | Persons, Organizations | Your Twitter/X handle (without @). | Medium: social identity link |
| LEI (Legal Entity Identifier) | P1278 | Organizations | Apply through an LEI issuer. Required for financial entities, optional for others. | High: financial and legal entity verification |
| GRID (Global Research Identifier Database) | P2427 | Research organizations | Applied automatically for research institutions. Can be requested. | High: academic and research entity linking |
| DUNS Number | P2771 | Organizations | Request from Dun & Bradstreet. May be assigned if you have existing credit records. | Medium: business credit and identity verification |
| Facebook ID | P2013 | Persons, Organizations | Found in your Facebook page URL. | Low-Medium: social cross-reference |
| YouTube Channel ID | P2397 | Persons, Organizations | Found in your YouTube channel URL. | Low-Medium: video platform cross-reference |
| ISBN publisher prefix | P3035 | Publishers | Assigned when you register as a publisher with your national ISBN agency. | Medium: publishing entity verification |
The ISNI Strategy
ISNI deserves special attention. The International Standard Name Identifier is managed by the ISNI International Authority and is used by libraries, publishers, and databases worldwide to uniquely identify entities. Google actively references ISNI data for entity disambiguation.
Obtaining an ISNI typically requires one of the following:
- Published works (books with ISBNs, academic papers, registered media).
- Institutional presence in a library catalog or authority file.
- Direct application through an ISNI registration agency.
For a business, having an ISBN (as a publisher) or being cataloged in a national library collection is the most reliable path to an ISNI. For a person, being a published author is the most common qualifier. If you have published a book with an ISBN, you likely already qualify.
VIAF: The Library Network
VIAF (Virtual International Authority File) aggregates authority records from national libraries worldwide. If any national library has cataloged a work by you or about your organization, VIAF may already have an entry for you. Check viaf.org by searching your name or organization.
VIAF is particularly powerful because it is managed by OCLC, the same organization that operates WorldCat (the world's largest library catalog). A VIAF entry means your entity is part of the global library authority infrastructure, a signal Google takes seriously.
External identifiers are not just database entries. They are cross-references that create a web of independent confirmations about your entity. Each identifier you add to your Wikidata item is another data point Google can use to verify that your entity is real, distinct, and accurately described.
Prioritization for Most Businesses
Not every business can obtain an ISNI or VIAF entry immediately. Here is a realistic prioritization:
- Immediate: LinkedIn Company ID (P4264), Twitter/X username (P2002), Facebook ID (P2013), YouTube Channel ID (P2397). These require only existing social accounts.
- Short-term (1-3 months): DUNS Number (P2771), LEI (P1278) if applicable. These require applications but have straightforward processes.
- Medium-term (3-12 months): ISNI (P213), VIAF (P214). These require published works or institutional cataloging. Plan for this by publishing a book with an ISBN or contributing to institutional collections.
Further Reading
- ISNI. "What is ISNI?" ISNI International Authority.
- VIAF. "Virtual International Authority File." OCLC.
- Wikidata. "Wikidata: Identifiers." Wikidata Help.
- GLEIF. "Introducing the Legal Entity Identifier (LEI)." Global Legal Entity Identifier Foundation.
Assignment
- Search VIAF (viaf.org) and ISNI (isni.org) for your name and business name. Document whether entries exist.
- Add all applicable social media identifiers to your Wikidata item: LinkedIn (P4264/P6634), Twitter (P2002), Facebook (P2013), YouTube (P2397).
- Determine whether you qualify for an ISNI. If you have published works with ISBNs, begin the application process.
- If you do not yet have a DUNS number, request one from Dun & Bradstreet.
- Create a tracking document listing every external identifier, its status (obtained, applied, not yet eligible), and the date you plan to add it to Wikidata.