Elements of a MARC Record

A MARC record is composed of three elements: the record structure, the content designation, and the data content of the record.

1. Record structure refers to the way various elements in a record are identified. For example, different types of information are recorded in fields which are identified by three numeric characters called tags. Record structure is an implementation of the international standard Format for Information Exchange (ISO 2709) and its American counterpart, Bibliographic Information Interchange (ANSI/NISO Z39.2) and is described by the various MARC formats. Record structure is fully described in MARC 21 Specifications for Record Structure, Character Sets, and Exchange Media.

Structural components: A MARC record consists of three main components: the Leader, the Directory, and the Variable Fields. (See: Components of a MARC Record.)

2. Content designation refers to the codes and conventions established explicitly to identify and further characterize the data elements within a record and to support the manipulation of that data. Content designation is defined by each of the MARC formats.

3. Content of the data elements that comprise a MARC record is usually defined by standards outside the formats, such as the International Standard Bibliographic Description (ISBD), Anglo-American Cataloguing Rules, Library of Congress Subject Headings (LCSH), or other cataloging rules, subject thesauri, and classification schedules used by the organization that creates a record. The content of certain coded data elements is defined in each of the MARC formats, e.g., the Leader, field 008.