What is the Core Principle of RDA?
At its heart, the core principle of RDA is to create data that is responsive to user needs in a networked, digital environment. It provides a flexible and extensible framework for describing all types of resources, from traditional books to digital files and multimedia. Unlike its predecessor, AACR2, which was structured around the linear display of card catalogs, RDA is rooted in a set of guiding principles from the International Federation of Library Associations and Institutions (IFLA) that prioritize the user's experience and the interoperability of data. The standard is not a display standard, but a content standard, focusing on the attributes and relationships that are most important for helping users find, identify, select, and obtain the resources they need.
The Foundation: Conceptual Models and User Tasks
To achieve its core principle, RDA is built upon foundational conceptual models that structure and organize bibliographic data in a more logical and user-centric way. The most significant of these are:
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Functional Requirements for Bibliographic Records (FRBR): This model organizes the bibliographic universe into four key entities to better reflect how users interact with information. RDA uses these entities to define data elements and relationships. The four entities are:
- Work: The abstract intellectual or artistic creation (e.g., the novel Moby Dick).
- Expression: The intellectual or artistic realization of a work (e.g., the English text of Moby Dick).
- Manifestation: The physical or digital embodiment of an expression (e.g., the Penguin Books hardcover edition of Moby Dick).
- Item: A single exemplar or copy of a manifestation (e.g., your specific copy of the Penguin hardcover).
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IFLA Library Reference Model (LRM): A later consolidation of FRBR and other functional requirements models (FRAD and FRSAD), LRM provides a more unified and robust entity-relationship model for guiding cataloging decisions in RDA.
These models inform the four crucial user tasks that RDA metadata is designed to support:
- Find: To locate a resource or set of resources using specified search criteria.
- Identify: To confirm that a particular resource is the one being sought.
- Select: To choose a resource that meets the user's specific needs.
- Obtain: To gain access to the resource, whether by borrowing, purchasing, or online access.
The Guiding Principles of RDA
Beyond the conceptual models, a set of underlying principles, derived from the IFLA Statement of International Cataloguing Principles, governs RDA's design and application. These ensure consistency and flexibility across different types of materials and systems.
- Convenience of the User: As the highest-rated principle, all cataloging decisions are made with the end-user in mind, ensuring the resulting data is comprehensible and useful. This contrasts with older standards that prioritized institutional practices.
- Representation: The description of a resource should accurately reflect how the resource presents itself. For instance, a person's name should be recorded as it appears on the resource itself, with controlled access points used to link variant forms.
- Accuracy: Descriptive data should be accurate, providing sufficient detail to distinguish a resource from others and clarify potentially misleading information.
- Consistency and Standardization: RDA promotes standardization to ensure consistency in descriptions and access points, which increases the ability to share and reuse bibliographic data across different systems.
- Interoperability: This principle emphasizes the sharing and reuse of bibliographic data both within and outside the library community. RDA's structure makes it compatible with various metadata schemas, including MARC, Dublin Core, and linked data formats like RDF.
Comparison of RDA and AACR2
To better understand the shift in cataloging, it's useful to compare RDA with its predecessor, AACR2. The transition highlights the fundamental change in principle from a rigid, print-centric system to a flexible, digital-first approach.
| Feature | AACR2 (Anglo-American Cataloguing Rules, 2nd ed.) | RDA (Resource Description and Access) |
|---|---|---|
| Principle | Structured around the constraints of the card catalog and a linear record display. | Principles-based standard for the digital, networked environment. |
| Data Model | Not explicitly based on an entity-relationship model. | Based on the FRBR and LRM conceptual models, focusing on entities and relationships. |
| Resource Types | Optimized for traditional print materials, with workarounds for new formats. | Comprehensive framework for describing all types of resources, analog and digital. |
| User Focus | Less explicitly user-focused, with conventions often favoring cataloger convenience. | Explicitly user-focused, designed to support the user tasks of Find, Identify, Select, and Obtain. |
| Carrier vs. Content | Mixed content and carrier information within the General Material Designation (GMD). | Separates content type, media type, and carrier type into distinct data elements. |
| Abbreviations | Required the use of standard library abbreviations. | Largely spells out abbreviations for clarity, especially in transcribed data. |
| Record Display | Tied to the International Standard Bibliographic Description (ISBD) punctuation format. | Separates data recording from presentation, allowing for flexible, technology-driven displays. |
Conclusion: Looking to the Future
By adhering to principles that prioritize user needs, accuracy, and interoperability, RDA offers a robust framework for managing information in the 21st century. Its basis in the IFLA conceptual models provides a logical, entity-centric structure that is highly adaptable to both the vast digital landscape and emerging linked data applications. The transition from AACR2 marked a crucial evolution, moving library cataloging from a system based on physical card displays to one designed for modern databases and online discovery. The principle of RDA ensures that library metadata is not just a description of an item, but a rich, interconnected web of data that facilitates resource discovery and remains relevant for a diverse community of users. [https://www.rdatoolkit.org/archivedsite/rdaprospectus.html]
