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Table of Contents: 2015 MAY–JUNE No. 404

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Discontinuing Distribution of Cataloging Bibliographic Records with Artificially Reconstructed Subject Strings—Comment by August 31, 2015

Boehr D. Discontinuing Distribution of Cataloging Bibliographic Records with Artificially Reconstructed Subject Strings—Comment by August 31, 2015. NLM Tech Bull. 2015 May-Jun;(404):e10.

2015 June 12 [posted]
2015 September 10 [Editor's note added]
2017 March 06 [corrected]

[Editor's note added on September 10, 2015: For updated information, see the article, Change to Subject Headings in Distributed NLM CATLINE and SERLINE Products.]

NLM has been recording geographic locations and publications types for cataloging in the MARC21 fields 651 and 655 respectively since 1999 to match NLM indexing practices for journal citations in subject assignment. This differs from the Library of Congress (LC) practice of putting geographic locations in 650 $z and publication types in 650 $v. In 1999, 80% of medical libraries responding to the announcement of this practice being adopted at NLM indicated that subjects in this 651 and 655 format would be difficult to incorporate in their Online Public Access Catalog (OPAC). NLM therefore continued to provide a specially programmed output with a traditional subject string of 650 $a $x $z $v for subscribers to Catfile. See the example at the end of this announcement.

In 2005, NLM once again asked the community for feedback and proposed discontinuing the special programming to create traditional subject strings and to distribute records as they appear in LocatorPlus. At that time, a small majority of libraries were in favor of such a proposal. However, those who were opposed were very passionate about the issue and made some compelling arguments for keeping the strings. NLM made some minor changes to the record distribution programs at that time to ease some of the complexities its catalogers had been encountering in trying to code subjects for proper output, but continued to output traditional subject strings.

It is now 10 years since this issue has been considered, and NLM believes that the environment has changed enough to once again propose discontinuing the practice of creating artificial subject strings for subscribers to Catfile. Rather than traditional OPACs, many libraries are using discovery systems that search across different input streams and provide faceted searching options. The library community is planning to make much more use of linked data, particularly with the future adoption of BIBFRAME. Long subject strings do not work well in a linked data environment, and, in fact, we are seeing many libraries breaking up the traditional Library of Congress Subject Headings (LCSH) subject string into its component parts using the Faceted Application of Subject Terminology (FAST) vocabulary. MeSH has recently been released in Resource Description Framework (RDF) triples that correspond to data in 650 $a and $x, 651, or 655 fields. NLM believes the time is now appropriate to stop creating artificial subject strings and distribute NLM records exactly as they appear in our database. This would mean that libraries that take copy from both NLM and OCLC would not have to edit one form or another to have consistency in their catalogs.

NLM is asking the medical library community to let us know what the effect would be on your institution if NLM were to discontinue distributing its MARC cataloging bibliographic records with artificially reconstructed subject strings. Records in MARC format would continue to have MeSH headings combined with the appropriate topical subheadings (650 $a $x), but geographic locations, and publication types would be carried in separate fields in the record, rather than as subfields of the MeSH heading. This would mean that records distributed to bibliographic utilities and other licensees would be identical to the records in LocatorPlus.

Please send your comments by August 31, 2015 to:

Diane Boehr
Head, Cataloging and Metadata Management Section
National Library of Medicine
8600 Rockville Pike, Room 1N11
Bethesda, MD 20894

NLM will announce the final decision on whether or not to implement this change by September 30, 2015. Any changes to distribution files will not occur until calendar year 2016.

Example of current practice:

In the NLM database:
650 12 $a Acquired Immunodeficiency Syndrome $x ethnology
650 22 $a Cross Cultural Comparison
650 22 $a Health Policy
651 _2 $a Africa $x ethnology
651 _2 $a Caribbean Region $x ethnology [Correction: $b ethnology was corrected to $x ethnology on March 6, 2017.]
655 _2 $a Congresses
Subject strings created for distribution:
650 12 $a Acquired Immunodeficiency Syndrome $x ethnology $z Africa $v Congresses
650 12 $a Acquired Immunodeficiency Syndrome $x ethnology $z Caribbean Region $v Congresses
650 22 $a Cross Cultural Comparison $z Africa $v Congresses
650 22 $a Cross Cultural Comparison $z Caribbean Region $v Congresses
650 22 $a Health Policy $z Africa $v Congresses
650 22 $a Health Policy $z Caribbean Region $v Congresses

By Diane Boehr
Cataloging and Metadata Management Section

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