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National Library of Medicine Technical BulletinNational Library of Medicine Technical Bulletin

Table of Contents: 2017 SEPTEMBER–OCTOBER No. 418

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Changes to Indicators for Some Subject Fields in MARC Records—Comment by October 31, 2017

Boehr D. Changes to Indicators for Some Subject Fields in MARC Records—Comment by October 31, 2017. NLM Tech Bull. 2017 Sep-Oct;(418):e6.

2017 September 25 [posted]

As part of our efforts to prepare our cataloging data for a linked data environment, the National Library of Medicine (NLM) has determined that some of the MARC coding for the subject fields is not accurate and will not create true triple statements in an RDF environment.

Historically, all MARC 6XX fields used in NLM bibliographic records have been assigned a second indicator of "2" defined as Medical Subject Headings (MeSH). This is true for data in the 650, 651, and 655 fields which are all taken from the MeSH vocabulary. However, data in the 600, 610, 611, and 630 fields does not come from MeSH, it comes from the National Authority File (NAF). Therefore, coding these fields with a second indicator of "2" is erroneous information. A second indicator of "0" (Library of Congress Subject Headings) would also not be correct. Although Library of Congress uses the NAF form for these subjects, LCSH practices for construction of name and title access points allow additions to these fields that NLM does not permit.

To accurately portray these subject fields, the second indicator should be "7" (Source specified in $2) with an accompanying $2 naf added to the 6XX field and NLM would like to make these changes in its files.

NLM recognizes that some libraries may rely on the second indicator in the 6XX fields for internal processing. Before making changes to our records, we are asking for community input on the impact to your organization or institution if indicators on the 600, 610, 611, and 630 fields were updated from "2" to "7" with the addition of a $2 naf. There may be positive as well as negative impacts. Libraries that are already converting MARC data into triples or have plans to do this in the near future will find that having accurate indicators in the records will more likely allow link resolvers to automatically find the correct data.

Please send your comments by October 31, 2017 to:

Diane Boehr
Head, Cataloging and Metadata Management Section
National Library of Medicine
8600 Rockville Pike, Room 1N11
Bethesda, MD 20894
boehrd@mail.nlm.nih.gov

No changes to cataloging records will be made until the comments are reviewed. Ample notification will be provided before any MARC changes are made.

By Diane Boehr
Head, Cataloging and Metadata Management Section

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