Profile Guide Step 3.7

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The use of subfield $v for form subdivisions (periodical, bibliography, etc.) was authorized in the MARC Bibliographic Format in 1995. Introduced first by NLM in MeSH headings, LC began distributing both bibliographic and authority records containing $v subfields in February, 1999. MARS 2.0 incorporated a number of enhancements to fully support subfield $v.

Step 3.7 Question


For Step 3.7, indicate if existing subfield $v codes should be preserved, and if all form subdivisions are to be updated to subfield $v codes. Mark both options if desired.

LC Standard Form

An increasing number of authority records include subdivisions coded as subfield $v. When a heading in a bibliographic record matches an authority record heading, MARS 2.0 modifies the subfield codes to conform to those in the authority record as part of the matching process.

	Original form:
	650   0	$aEnglish literature$xHistory and criticism$xPeriodicals.

	New form:
	650   0	$aEnglish literature$xHistory and criticism$vPeriodicals.


Many libraries have begun coding form subdivisions as subfields $v in their new catalog records. MARS 2.0 can preserve your subfield $v codes in subject headings regardless of the existence of an LC authority record for the heading. For example, if a library had created a bibliographic record with the following heading:

	Library bibliographic heading for database about stock prices:
	650   0	$aStocks$xPrices$vDatabases.

	LC authority record sh 87003018:
	650   0	$aStocks$xPrices$xDatabases.

Selection of the Preserve existing $v option in Step 3.7 would preserve the subfield $v code, even though the LC authority record coded Databases as a subfield $x. The heading left on the bibliographic record would be the library’s original heading:

	650   0	$aStocks$xPrices$vDatabases.

Update Headings

You can also elect to have all form subdivisions coded as subfield $v:

If the heading above was present in your database, with Databases coded as subfield $x:

	650   0	$aStocks$xPrices$xDatabases.

This MARS 2.0 option would convert your bibliographic heading to the new subfield $v code form whether or not an authority record contained that form.

MARS 2.0 programs only modify a subfield code if the subfield meets a number of specific conditions, set by LC and MARC21. To be eligible for updating to the subfield $v code, the subfield must be:

  • Part of a subject (6XX) heading
  • The last subfield, or last pair of subfields, in a heading


  • Eligible subfields can be followed by geographic subfields $z
  • Eligible subfields can be followed by a subfield $x containing a language

Other exceptions are also supported by the MARS 2.0 subfield $v software and are found in our programming set of rules. The MARS 2.0 staff has made many additional changes to other MARS 2.0 tables so that obsolete subdivisions will be updated to the correct subfield $v form. If you have a question about a particular $v conversion, please contact your Project Manager.

MARS 2.0 programs apply an extensive table of over a thousand form subdivisions consisting of both single and multiple subfields to subfield $v processing. This table was developed based on LC and MARC21 form subdivision documents, plus analysis of library headings by the MARS 2.0 Authority Control team. Subdivisions that can be correctly coded by either a subfield $x or $v are always converted to a subfield $v if this option is selected.

A report of all headings containing ambiguous headings that have been flipped to subfield $v is available for review by the library (see Step 5, report R39).

Two subdivisions that appear at the end of a heading are not converted to $v subfields unless the pair has been included as an acceptable combination in the form subdivision table.

In the following heading, both Gazetteers and Bibliography can be form subdivisions:

	651   0	$aFrance$xGazetteers$xBibliography.

The combination of these 2 headings, however, is not an authorized form subdivision, so only the final subfield would be recoded as a subfield $v. The updated heading would be:

	651   0	$aFrance$xGazetteers$vBibliography.

Authority Records

The MARS 2.0 processes described previously in this section are applied to bibliographic headings only. Many LC authority records contain potential form subdivisions coded as subfield $x. Both preserving subfield $v codes you enter and having MARS 2.0 update form subdivisions to the subfield $v code will result in bibliographic headings coded differently than the established headings in LC authority records.

The following examples show some headings from bibliographic records with differing subfield coding and the form of the heading in the LC authority records, which would be distributed to the library:

 	Bibliographic record (for a work about early maps, in which the cartographic material is secondary):
 	651   0	$aUnited States$xMaps$xEarly works to 1800.

 	Bibliographic record (for a work containing actual maps or reproductions):
 	651   0	$aUnited States$vMaps$vEarly works to 1800.

 	Authority record LC ARN sh 86006684 (distributed for both forms of the heading shown above):
 	151    	$aUnited States$xMaps$xEarly works to 1800

 	Bibliographic record (for a work about various collections of manuscripts):
 	650   0	$aManuscripts$xCollections.

 	Bibliographic record (for a work containing a collection of manuscripts):
 	650   0	$aManuscripts$vCollections.

 	Authority record LC ARN sh 85080674 (distributed for both forms of the heading shown above):
 	150    	$aManuscripts$vCollections

Note: MARS 2.0 is not currently providing LC subdivision (18X) authority records. The MARS 2.0 staff is interested in discussing any situation in which distribution of subdivision authority records would be beneficial within your current local system.

National Authority Files

MARS 2.0 processing can match bibliographic headings against headings in the LC Name and Subject Authority Files. The LC Authority Files contain over 7 million authority records. About 8,000 new and updated authority records are received in LC weekly updates.

Fields Matched

The following fields are matched against the LC Authority Files:

  • Only those with a 2nd indicator of zero (those with a 2nd indicator of ‘blank’ will be changed to a zero and matched


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