MARC 21 Concise Classification: Introduction

This is an ARCHIVED VERSION of the 2001 electronic edition of the MARC 21 Concise Formats. Please see
www.loc.gov/marc/concise/ for the most up-to-date version of the electronic MARC 21 Concise Formats.

The MARC 21 Format for Classification Data is designed to be a carrier for information about classification numbers and the captions associated with them that are formulated according to a specified authoritative classification scheme.

Kinds of Classification Records

MARC classification records are distinguished from all other types of MARC records by code w (Classification data) in Leader/06 (Type of record). The MARC 21 Format for Classification Data further identifies three kinds of classification data records in 008/06 (Kind of record):

Schedule record - A record in which the classification number or number span in field 153 $a (Classification Number) is taken from a schedule.

Table record - A record in which the base number of the classification number or number span in field 153 is taken from a table.

Index term record - A record in which field 154 (General Explanatory Index Term) contains an index term that is an explanatory term representing a concept and cannot be associated with a classification number. An index-term-only record must also contain explanatory text in field 753 (Index Term--Uncontrolled).

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Types of Numbers

The MARC classification record is an authority record for the classification number(s) and caption contained in field 153 (Classification Number). Classification numbers with captions may also appear in fields 453 (Invalid Number Tracing) and 553 (Valid Number Tracing). Index term only records contain an index term in field 154 (General Explanatory Index Term) instead of a classification number and caption in field 153. Three types of classification numbers are defined in the classification format and identified in 008/07 (Type of classification number):

Single number - A single classification number is one classification number contained in subfield $a (Single number or beginning number of span) in a record.

Defined number span - A defined number span is a range of classification numbers with a beginning number contained in subfield $a and an ending number contained in subfield $c (Ending number of span). The numbers between the beginning and ending numbers are defined by a separate table or subarrangement.

Summary number span - A summary number span is also a range of classification numbers with a beginning and an ending number. The caption contained in subfield $j (Caption) summarizes a topic that is represented by the span in subfields $a and $c. A summary number span is not defined by a separate table or subarrangement; instead, the numbers falling within the span are generally defined separately by their own records.

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Classification Number Usage in Bibliographic and Authority Records

MARC bibliographic records may contain classification numbers in fields 050-09X. MARC authority records may contain classification numbers in fields 053 (LC Classification Number), 083 (Dewey Decimal Classification Number), etc. Classification numbers may be valid, invalid or, in the case of a span, partially valid. A valid classification number may be used in a bibliographic or authority record by itself or with additional letters or numbers. In the case of a span, a portion of it may be used in a bibliographic record. In addition a number that has been synthesized by correctly applying a table, internal subarrangement or add instructions to a classification number or span is considered valid for use in a bibliographic or authority record; a classification record may or may not be created for synthesized numbers or numbers within spans.

A partially valid classification number span is one in which only the beginning or ending number of a span is valid. Only the valid portion may be used in bibliographic or authority records. An invalid number may not be used in a bibliographic or authority record. However, a classification record may be created for an invalid number in cases where the reference information cannot be communicated by a simple 453 tracing because a more detailed reference note is required. Invalid numbers in a 153 field of an invalid record or in a 453 field (Invalid Number Tracing) may not be used in bibliographic or authority records.

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Required Classification Data Fields

A classification data record should contain at a minimum the following fields:

• 008 - Fixed-Length Data Elements
• 084 - Classification Scheme and Edition
• 153 - Classification Number;
  or
• 154 - General Explanatory Index Term

A record with field 154 must also contain field 753 (Index Term--Uncontrolled).

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Typographical Conventions

Throughout this document, the following typographical conventions are used:

0 - The graphic 0 represents the digit zero in tags, fixed-position character position citations, and indicator positions. This character is distinct from an uppercase letter O used in examples or text.

# - The graphic symbol # is used for a blank (hex 20) in coded fields and in other special situations where the existence of the character blank might be ambiguous.

$ - The graphic symbol $ is used for the delimiter (hex 1F) portion of a subfield code. Within the text, subfield codes are referred to as subfield $a, for example.

/ - Specific character positions of fixed-length data elements, such as those in the Leader, Directory, and field 008, are expressed using a slash and the number of the character position, e.g., Leader/06.

1 - The graphic 1 represents the digit one (hex 31) and the lowercase roman-alphabet letter l (eye) (hex 6C) in examples or text.

| - The graphic | represents a fill character (hex 7C).

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Organization of the Electronic Version of the Concise Format

This electronic concise format is organized into parts that generally mirror the tabbed sections of the full printed format documentation. Each part is divided into chapters that usually cover a single field and all the data elements possible within it (that is, character positions for fixed-length fields and indicators and subfield codes for variable length fields). The Leader and the Directory are described in the first main part, followed by parts containing the variable control fields and variable data fields arranged in numerical field tag order.

Obsolete and deleted content designators are not listed. They are found the full printed version of the format and in the electronic MARC field lists.

Information for Translators and Other Users
Items highlighted in red indicate changes made after the 2000 edition of the MARC 21 Concise Formats was published and are included in the 2001 printed edition of the MARC 21 Concise Formats.

Items highlighted in green indicate changes made to the online format only. These changes will be corrected in the 2002 printed edition of the MARC 21 Concise Formats (Available late 2002).

For information about ordering the full MARC 21 Format for Classification Data, please see: Print | CD-ROM

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