These codes may be used wherever there is a need to refer to a controlled vocabulary, rule set, or scheme, but in particular they are intended for use with MARC and MODS/MADS data.  (MODS =Metadata Object Description Schema; MADS = Metadata Authority Description Schema)

For newly assigned codes, a date is given before which the code should not be included in exchange records.  The date represents a 60-day waiting period required to allow MARC and MODS/MADS implementers time to add newly assigned codes to any validation tables they may use to check the codes recorded in records.  Implementers may use newly assigned codes in their internal systems immediately as long as records containing new codes are not distributed until after the waiting period.

See also: