MARC 21:

User groups may have full level and minimal level record requirements to promote consistency across cataloging agencies.  These should be widely publicized so that all possible interchange partners can be aware of them.

In the United States:

In the Cataloger's Reference Shelf, national and minimal level requirements in the United States are displayed in table form for variable data fields in bibliographic records.  For authority records, only national level record requirements are displayed.

Full level MARC bibliographic and authority records that are contributed to a national database must follow the content requirements as specified by the terms listed below.  These terms (or their one-letter codes) can be found with the definitions of the indicators and subfield codes for each field.  The term full level and other encoding level categories are defined in Leader/17.

General information:

National-level records are required to contain sufficient cataloging information to allow them to be used by various agencies nation- and world-wide.  National level record requirements were developed for most types of material between 1979 and 1981.  Requirements for computer files and mixed materials were not added until the 1988 edition of the bibliographic format.

Minimal-level records are required to contain only essential cataloging information, although additional data may be provided.

The national level and minimal level record requirements are not intended to prevent a cataloging agency from using any valid MARC data element.  They are provided to facilitate the standardization of the content of MARC 21 records.

The national-level requirement categories and codes:

To view the national level or minimal level requirements of any field or its indicators or subfields, select that field for more information.

Three different codes are used to differentiate between data elements that must always be present, that should be present when information is available, and optional data elements.  The requirement codes are defined as follows:

Mandatory.  The data element must be present in the full level national level record.  The fill character ( | ) is not permitted in mandatory data elements.  The code M is sometimes used to represent this requirement.

Mandatory if applicable.  The data element must be present in the record if it is appropriate for the item being described and if the information is available.  The fill character ( | ) is not permitted in data elements that are Mandatory if applicable.  The code A is sometimes used to represent this requirement.

Optional.  An optional data element is not required in the record, but may be present if desired.  The fill character ( | ) is permitted in some optional character positions.  (See:  Fill Character and Related Values.)  The code O is sometimes used to represent this term.

No national level or minimal level requirement codes are specified in MARC 21 Format for Classification Data, MARC 21 Format for Community Information, or MARC 21 Format for Holdings Data.

Indicator positions:

In MARC 21, a valid value is mandatory in both indicator positions for fields that include indicator positions.  In the MARC 21 formats, this includes fields 010 through 8XX and any locally-defined fields within the 010 to 999 range that may be used by a cataloging agency.  When an indicator position is present but undefined, a blank is always used.  The fill character ( | ) is never used in indicator positions in MARC 21.  Since valid indicator values are mandatory in all MARC 21 fields (except 001-008), no national level requirements are given.  If a field is present in a record, valid indicator values must be supplied.  The individual field descriptions provide listings of valid indicator values.

To return:

A General Introduction to the MARC Format