AACR2RDA

AACR2RDA refers to a transitional set of cataloging practices used by libraries during the move from AACR2 (Anglo-American Cataloguing Rules, Second Edition) to RDA (Resource Description and Access). It is not a formal successor standard, but a shorthand for guidelines that blend AACR2 instructions with emerging RDA principles to support continued cataloging while migrating data, training staff, and updating workflows.

The purpose of AACR2RDA is to preserve data quality and interoperability as library metadata shifts from rule-based AACR2 to the more principle-based RDA framework. It emphasizes adopting RDA's FRBR-based concepts—such as treating works, expressions, manifestations, and items as distinct entities—while allowing libraries to apply familiar AACR2 practices where feasible during the transition.

Typical features include dual or phased application of rules for access points, titles, and statements of responsibility; gradual incorporation of RDA elements (such as preferred sources of information and updated punctuation guidance); and continued use of MARC 21 as the encoding format with mappings from RDA data to MARC fields. The approach supported ongoing cataloging, discovery, and authority work without requiring an immediate rewrite of existing records.

Adoption of RDA and related transitional practices varied by institution and region, with many libraries moving toward full RDA implementation over the subsequent years. Related standards include AACR2, RDA, FRBR, FRAD, and MARC 21.