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ISO 27729: International Standard Name Identifier (ISNI)
The ISNI system for unique identification of public identities in the media content industries
Introduction to ISO 27729 and the ISNI System
ISO 27729:2024 defines the International Standard Name Identifier (ISNI), a 16-digit identifier system for the unique identification of public identities of parties involved in the media content industries. The ISNI serves as a “bridge” identifier that connects proprietary databases across different sectors — publishing, music, film, broadcasting — without requiring the disclosure of confidential business information. The standard was prepared by ISO/TC 46/SC 9 (Identification and description) and represents the second edition, replacing ISO 27729:2012.
The ISNI system now assigns millions of identifiers worldwide, enabling unambiguous identification of authors, performers, producers, and corporate entities across all creative industries. It is the backbone identifier linking Wikidata, VIAF, and numerous national library systems.
ISNI Structure and Check Character Calculation
An ISNI consists of 15 decimal digits plus a check character (which may be a digit or “X”), calculated using the ISO/IEC 7064 MOD 11-2 algorithm. The identifier is deliberately “dumb” — no semantic meaning is embedded in any part of the number. When presented in human-readable form, it is formatted as four blocks of four digits preceded by the letters “ISNI”:
ISNI 1422 4586 3573 0476
| Component | Description | Example |
|---|---|---|
| Prefix | Letters “ISNI” followed by space | ISNI |
| Base number | 15 decimal digits | 1422 4586 3573 047 |
| Check character | 1 decimal digit or “X” | 6 |
| Display format | 4 blocks of 4 digits separated by spaces | 1422 4586 3573 0476 |
| Weighting | MOD 11-2 algorithm per ISO/IEC 7064 | wi = 2(i-1) mod 11 |
The MOD 11-2 check character system guards against common transcription errors such as single-digit errors, adjacent digit transpositions, and jump transpositions. The check character is always in the extreme right (low order) position and ensures that the weighted sum of all 16 digits is congruent to 1 (mod 11).
Allocation Principles and Practical Applications
ISO 27729 establishes eight fundamental allocation principles. Key among them: one ISNI per public identity, with alternative spellings and script variants not justifying separate ISNIs, but multiple public identities of the same party (e.g., pseudonyms) receiving distinct ISNIs. The standard also specifies that once allocated, an ISNI shall never be re-used — a critical persistence guarantee for long-term reference integrity.
The registration metadata includes the name of the public identity, type of party (natural person, legal person, or group), external data links, creation class (e.g., literary work, musical work), and role (author, performer, etc.). The ISNI system is administered by the ISNI Registration Authority, which maintains the central register and ensures system integrity.
Engineers integrating ISNI into content management systems must note that the check character “X” represents the value 10 in the MOD 11-2 algorithm. This is a common source of validation errors in database implementations that expect purely numeric identifiers.
Frequently Asked Questions
Q: How does ISNI differ from ORCID or other researcher identifiers?
A: ISNI covers all public identities across all creative fields (authors, musicians, performers, corporate entities), while ORCID is specifically for academic researchers. ISNI and ORCID have a collaborative relationship — ORCID IDs can be mapped to ISNIs through a bridged registration process.
A: ISNI covers all public identities across all creative fields (authors, musicians, performers, corporate entities), while ORCID is specifically for academic researchers. ISNI and ORCID have a collaborative relationship — ORCID IDs can be mapped to ISNIs through a bridged registration process.
Q: Can an individual have multiple ISNIs?
A: Yes. Multiple public identities of the same party (e.g., pen names, stage names) each receive separate ISNIs. The metadata set can link related ISNIs through the “related identifier” and “relationship” elements (e.g., “is the pseudonym of”).
A: Yes. Multiple public identities of the same party (e.g., pen names, stage names) each receive separate ISNIs. The metadata set can link related ISNIs through the “related identifier” and “relationship” elements (e.g., “is the pseudonym of”).
Q: What happens if an ISNI is assigned in error?
A: The standard explicitly prohibits re-use of an ISNI, even if issued in error. The erroneous record is retained but can be marked as deprecated. A new ISNI is assigned for the correct identity.
A: The standard explicitly prohibits re-use of an ISNI, even if issued in error. The erroneous record is retained but can be marked as deprecated. A new ISNI is assigned for the correct identity.
Q: How does ISNI interact with other ISO identification standards?
A: ISNI serves as the party identifier that links across ISBN (books), ISSN (serials), ISRC (recordings), ISMN (music), ISAN (audiovisual works), and ISWC (musical works). It identifies the contributors behind these resources, not the resources themselves.
A: ISNI serves as the party identifier that links across ISBN (books), ISSN (serials), ISRC (recordings), ISMN (music), ISAN (audiovisual works), and ISWC (musical works). It identifies the contributors behind these resources, not the resources themselves.
