IFLAThe IFLA Library Reference Model (IFLA LRM) is a high-level conceptual entity-relationship model that provides the intellectual foundation for structuring bibliographic and authority data in libraries. Published in August 2017 by the International Federation of Library Associations and Institutions (IFLA), it unifies three predecessor models into a single coherent framework and serves as the conceptual basis for modern cataloguing standards, most notably Resource Description and Access (RDA).
Background
IFLA LRM emerged from the recognition that three separately developed conceptual models contained overlapping and sometimes inconsistent definitions. The Functional Requirements for Bibliographic Records (FRBR, 1998) focused on the bibliographic universe of works and their manifestations; the Functional Requirements for Authority Data (FRAD, 2009) addressed authority data for controlled access points; and the Functional Requirements for Subject Authority Data (FRSAD, 2010) dealt with subject authority data.
The IFLA Committee on Standards established a Consolidation Editorial Group, chaired by Pat Riva, to merge these three models. After extensive review and a worldwide public comment period, the final text was endorsed by the IFLA Professional Committee in August 2017 and published as "IFLA Library Reference Model: A Conceptual Model for Bibliographic Information" (IFLA Series on Bibliographic Control, volume 44), authored by Pat Riva, Patrick Le Boeuf, and Maja Zumer.
Purpose & Scope
IFLA LRM serves as an abstract reference model for the bibliographic universe. It defines:
- The fundamental entities that exist in the domain of library cataloguing
- The attributes of those entities
- The relationships between entities
The model is designed to be implementation-independent. It does not prescribe specific cataloguing rules or encoding formats, but provides the conceptual vocabulary upon which such rules and formats can be built. Its primary audiences are cataloguing rule makers, metadata schema designers, library system developers, and library science researchers. It has Library of Congress subject heading number 2017004509.
Key Entities
IFLA LRM defines eleven entity types organized in a hierarchy:
| Entity | Definition |
|---|---|
| Res | Superclass for all entities ("thing") |
| Work | A distinct intellectual or artistic creation |
| Expression | An intellectual or artistic realization of a work |
| Manifestation | A physical embodiment of an expression of a work |
| Item | A single exemplar of a manifestation |
| Agent | An entity capable of deliberate actions |
| Person | An individual human being |
| Collective Agent | A gathering or organization of persons |
| Nomen | An association between an entity and a designation |
| Place | A geographic location |
| Time-span | A temporal extent |
The Work-Expression-Manifestation-Item (WEMI) stack, inherited from FRBR, remains the backbone of the model.
Differences from FR-Series Models
Key structural changes from the predecessor models include:
- Addition of super-classes Res ("thing") and Agent to facilitate formal relationship definitions
- Time-span and Place are entities rather than literal values
- FRBR Group 2 corporate body and FRAD family are combined into a single Collective Agent type
- FRBR Group 3 entities are deprecated
- A redefined Nomen type encompasses name from FRAD plus nomen, identifier, and controlled access point from FRSAD
Serializations & Technical Formats
The IFLA Standards site publishes an RDF expression of IFLA LRM as the "LRMer" element set (LRM entity-relationship), which defines native RDF classes and properties corresponding to the model's entities, attributes, and relationships. These are available in both constrained and unconstrained forms for Semantic Web use. The namespace base is http://iflastandards.info/ns/lrm/lrmer/.
Governance & Maintenance
IFLA LRM is maintained under the authority of the IFLA Committee on Standards. The RDF vocabularies on iflastandards.info are maintained alongside other IFLA namespace registrations (ISBD, FRBR, UNIMARC) with source files on GitHub. Updates to the vocabularies follow IFLA's review and approval processes.
Notable Implementations
The most significant implementation of IFLA LRM is its adoption as the underlying conceptual model for Resource Description and Access (RDA). The 2019 RDA Toolkit restructuring (the "3R Project") explicitly aligned RDA's vocabulary and structure with IFLA LRM entities and relationships.
Library system vendors have incorporated LRM-based data models into their next-generation systems. The model also informs discussions about future MARC format evolution and its potential successors in the BIBFRAME initiative.
Related Standards
- FRBR, FRAD, FRSAD -- the three predecessor models that LRM consolidates and replaces
- ISBD -- the International Standard Bibliographic Description, whose elements map to LRM entities
- RDA -- the cataloguing standard built on LRM's conceptual framework
- BIBFRAME -- the Library of Congress's linked data initiative, a related approach to modeling bibliographic data
- FRBRoo -- the object-oriented mapping of FRBR to the CIDOC CRM
- CIDOC Conceptual Reference Model -- a related conceptual model for cultural heritage