Resource Description and Access
Resource Description and Access (RDA) is a standard for cataloguing that provides instructions and guidelines on formulating data for resource description and discovery. Intended for use by libraries and other cultural organizations such as museums and archives, RDA is the successor to the Anglo-American Cataloguing Rules, Second Edition (AACR2), the current cataloging standard set for English language libraries. RDA was initially released in June 2010.  In March 2012, the Library of Congress announced it will have fully implemented RDA cataloging by March 31, 2013. Several other national libraries including the British Library, Library and Archives Canada, National Library of Australia, and Deutsche Nationalbibliothek also planned to implement RDA in 2013.
RDA emerged from the International Conference on the Principles & Future Development of AACR held in Toronto in 1997. It was quickly realised[by whom?] that substantial revision of AACR2 was required, which encouraged the adoption of a new title for what had been envisaged as a third edition of AACR.
The primary distinction between RDA and AACR is structural. RDA is organised based on the Functional Requirements for Bibliographic Records (FRBR). These principles identify both the 'user tasks' which a library catalog should make possible and a hierarchy of relationships in bibliographic data. Descriptions produced using the instructions of RDA are intended to be compatible with any coding schema, including the data environments used for existing records created under the AACR2 rules.
RDA is published jointly by the American Library Association, the Canadian Library Association, and the Chartered Institute of Library and Information Professionals (CILIP) in the UK. RDA instructions and guidelines are available through RDA Toolkit, an online subscription site, and in a print format. Maintenance of RDA is the responsibility of the Joint Steering Committee for the Development of RDA (JSC). The JSC is composed of representatives from the American Library Association, the Australian Committee on Cataloguing, the British Library, the Canadian Committee on Cataloguing, CILIP, Deutsche Nationalbibliothek, and the Library of Congress.
In the U.S., the cataloguing community expressed reservations about the new standard in regard to both the business case for RDA in a depressed economy and the value of the standard's stated goals.Michael Gorman, one of the authors of AACR2, was particularly vocal in expression of his opposition to the new guidelines, claiming that RDA was poorly written and organized, and that the plan for RDA unnecessarily abandoned established cataloging practices. In response to these concerns, the three United States national libraries (Library of Congress, National Library of Medicine, and the National Agricultural Library) organized a nation-wide test of the new standard.
U.S. RDA Test Coordinating Committee report
On 13 June 2011, the Library of Congress, the National Agricultural Library, and the National Library of Medicine released the results of their testing. The test found that RDA to some degree met most of the goals that the JSC put forth for the new code and failed to meet a few of those goals. The Coordinating Committee admitted that they "wrestled with articulating a business case for implementing RDA", nevertheless the report recommended that RDA be adopted by the three national libraries, contingent on several improvements being made. The earliest possible date for implementation was given as January 2013, as the consensus emerging from the analysis of the test data showed that while there were discernible benefits to implementing RDA, these benefits would not be realized without further changes to current cataloging practices, including developing a successor to the MARC format.
RDA was developed to be an international standard and is in step with the Statement of International Cataloguing Principles published by IFLA in 2009. RDA is also in step with established international display and encoding standards.  The emergence of the European RDA Interest Group (EURIG) and the addition of the Deutsche Nationalbibliothek as a member of the JSC  signaled interest in RDA beyond the English-speaking library community.
The first set of RDA Vocabularies were published on the Open Metadata Registry in August 2011. The creation and publication of stable forms of RDA elements and controlled vocabularies/concepts makes RDA-created data accessible as open linked data for builders of applications. Alan Danskin, Chair of the Joint Steering Committee in 2011, noted, "The RDA vocabularies are a fundamental component of RDA, promoting consistent description and discovery of bibliographic resources. The Committee is committed to publishing and maintaining the content of the RDA vocabularies, synchronized with the text of RDA, in order to support their use by the resource description community and by developers of Semantic Web applications." 
RDA versus AACR2
The major difference between RDA and AACR2 is that RDA deliberately avoids making any provisions as to how data should actually display – it is independent of any specific display standard. This means that the punctuation rules like AACR2 is absent in RDA. The data display in RDA will be made externally to itself, by individual cataloging agencies, national library institutes, or library software vendors. RDA treats each element of data in a record as a separate entity in its own right, and its rules make no statements as to the order or sequence in which these elements should be presented in a print or screen display. Inaccuracies that appear in the source itself, i.e., misspellings on a book’s title page, will no longer be signaled through the use of [sic]. Instead, obvious errors are corrected, and a note is made giving the wording as it actually appears on the item (rule 220.127.116.11). RDA dispenses with AACR2’s General Material Designators (GMDs) – the bracketed phrases like [Sound recording] or [Electronic resource] that practicing catalogers are all familiar with. Instead, the cataloger is asked to record three separate data elements: Content type (such as text, performed music, spoken word, still image, etc.), see RDA 6.9.1. Media type (this essentially expresses whether or not some type of equipment is needed in order to access the resource, such as audio [player], video [player], computer, unmediated, etc.), see RDA 3.2.1. Carrier type (expresses the actual physical form of the resource, for example audio disc, microfilm reel, volume, etc.), see RDA 3.3.1. It should be noted that Content type is an attribute of the expression, so it is treated at the expression level, in Chapter 6 (rule 6.9.1). Media type and Carrier type are both attributes of the manifestation, so they are treated in Chapter 3. The decision to abandon AACR2’s General Material Designators resulted, I believe, from a desire to stay true to the internal logic of the FRBR model. The problem with the General Material Designators, from the RDA point of view, is that they can’t consistently be placed in a one-to-one relationship to a specific level of the FRBR bibliographic hierarchy: “sound recording,” for example, may be intended to express content type, which is an attribute of the expression, but it can equally be intended to express the media or carrier types, which are attributes of the manifestation. In order to avoid the inevitable logical confusions, RDA opts to replace the GMDs with the more rigorously defined content, media, and carrier types. One term that is bound to cause some initial consternation is “unmediated,” in the list of media types. The media type terms are used to designate pieces of equipment needed to access a particular resource. The term “unmediated” is used if no equipment is required. Thus “unmediated” becomes the media type that RDA uses to describe a printed book: Content type = text. Media type = unmediated. Carrier type = volume. 
- Joint Steering Committee for Development of RDA. "RDA: Resource Description and Access - Background". Retrieved 28 March 2012.
- Library of Congress. "Library of Congress Announces Its Long-Range RDA Training Plan". March 2, 2012. Retrieved 28 March 2012.
- Joint Steering Committee for Development of RDA. International Conference on the Principles & Future Development of AACR.
- Oliver, Chris (2010). Introducing RDA: a guide to the basics. ALA Editions. p. 128. ISBN 978-0-8389-3594-1.
- Joint Steering Committee for Development of RDA. "Overview". Retrieved 28 March 2012.
- Library of Congress Working Group on the Future of Bibliographic Control. "Testing Resource Description and Access (RDA)". Retrieved 31 January 2011.
- Gorman, Michael. "RDA: The coming cataloguing debacle". Retrieved 31 January 2011.
- "Report and Recommendations of the U.S. RDA Test Coordinating Committee on the implementation of RDA—Resource Description & Access". Retrieved 15 June 2011.
- Library of Congress. "A Bibliographic Framework for the Digital Age". 31 October 2011. Retrieved 28 March 2012.
- Joint Steering Committee for Development of RDA. "Outcomes of the Meeting of the Joint Steering Committee Held in Glasgow, Scotland, 1-4 November 2011". Retrieved 28 March 2012.
- Joint Steering Committee for Development of RDA. "First RDA Vocabularies Published." 1 August 2011. Retrieved 28 March 2012.
- Croissant, J Charles R. FRBR and RDA: What They Are and How They May Affect the Future of Libraries