MARC standards

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Filename extension .mrc, .marc
Internet media type application/marc

MARC (MAchine-Readable Cataloging) standards are a set of digital formats for the description of items catalogued by libraries, such as books. Working with the Library of Congress, American computer scientist Henriette Avram developed MARC in the 1960s to create records that could be read by computers and shared among libraries.[1] By 1971, MARC formats had become the national standard for dissemination of bibliographic data in the United States, and the international standard by 1973. There are several versions of MARC in use around the world, the most predominant being MARC 21, created in 1999 as a result of the harmonization of U.S. and Canadian MARC formats, and UNIMARC, widely used in Europe. The MARC 21 family of standards now includes formats for authority records, holdings records, classification schedules, and community information, in addition to the format for bibliographic records.

Record structure and field designations[edit]


Field designations[edit]

Each field in a MARC record provides particular information about the item the record is describing, such as the author, title, publisher, date, language, media type, etc. Since it was first developed at a time when computing power was low, and space precious, MARC uses a simple three-digit numeric code (from 001-999) to identify each field in the record. MARC defines field 100 as the primary author of a work, field 245 as the title and field 260 as the publisher, for example.


Record structure[edit]




MARC encodes information about a bibliographic item, not about the content of that item; this means it is a metadata transmission standard, not a content standard. The actual content that a cataloger places in each MARC field is usually governed and defined by standards outside of MARC, except for a handful of fixed fields defined by the MARC standards themselves. Resource Description and Access, for example, defines how the physical characteristics of books and other items should be expressed. The Library of Congress Subject Headings (LCSH) are a list of authorized subject terms used to describe the main subject content of the work. Other cataloging rules, subject thesauri, and classification schedules can also be used.

MARC formats[edit]

MARC formats
Name Description
Community Information records MARC records describing a service-providing agency, such as a local homeless shelter or tax assistance provider.

MARC 21[edit]






The MARCXML primary design goals included:[5]

  • Simplicity of the schema
  • Flexibility and extensibility
  • Lossless and reversible conversion from MARC
  • Data presentation through XML stylesheets
  • MARC records updates and data conversions through XML transformations
  • Existence of validation tools


The future of the MARC formats is a matter of some debate among libraries. On the one hand, the storage formats are quite complex and are based on outdated technology. On the other, there is no alternative bibliographic format with an equivalent degree of granularity. The billions of MARC records in tens of thousands of individual libraries (including over 50,000,000 belonging to the OCLC consortium alone) create inertia. The Library of Congress has launched the Bibliographic Framework Initiative (BIBFRAME),[6] which aims at providing a replacement for MARC that provides greater granularity and easier re-use of the data expressed in multiple catalogs.[7] Beginning in 2013, OCLC Research exposed data detailing how various MARC elements have been used by libraries in the 330 million MARC records contained in WorldCat.[8]

See also[edit]


  2. ^ a b Taylor, Organization of Information, p77
  3. ^ "Character Sets: MARC-8 Encoding Environment: MARC 21 Specifications for Record Structure, Character Sets, and Exchange Media (Library of Congress)". 
  8. ^ "MARC Usage in WorldCat". OCLC Research. 2013. Retrieved April 8, 2015. 

Further reading[edit]

External links[edit]