Standards Used in Cataloging
RDA: Resource Description and Access serves as the current authority for descriptive cataloging at NLM. These rules are supplemented by the LC-PCC Policy Statements which appear in the RDA Toolkit. Bibliographic records are formatted according to MARC21 Format for Bibliographic Data. RDA has replaced the Anglo-American Cataloging Rules, 2nd ed. (AACR2) as of March 31, 2013.
Personal and corporate access points appearing in most cataloging records follow either AACR2 rules or RDA guidelines. Some records were cataloged prior to the adoption of AACR2 and thus, the headings used may reflect earlier cataloging practices. NLM has been submitting authority records to NACO (Name Authority Cooperative Program of the PCC) for its English language material since 1985. Beginning in March 2012, NLM has been submitting all authority records to NACO. The authority records are formatted according to MARC21 Format for Authority Data.
NLM applies multi-level description in the cataloging of monographs: full level descriptive cataloging, Bibliographic Standard Record (BSR)-level cataloging following the standards promulgated by the Program for Cooperative Cataloging (PCC), and NLM's minimal level or "Limited cataloging." Serials are cataloged following the CONSER Standard Record (CSR) guidelines or NLM’s minimal level cataloging standard. Details of the various levels of description used at NLM in the cataloging of monographs and serials are documented in NLM Cataloging Section: Definition of Cataloging Levels. Details of the various levels of description used at NLM in the cataloging of monographs and serials are documented in NLM Cataloging Section: Definition of Cataloging Levels.
- Subject Headings
The subject headings used in cataloging are from Medical Subject Headings(MeSH®), NLM's controlled vocabulary, which is used in the preparation of MEDLINE®, and PubMed®, as well as for subject cataloging. NLM assigns subject headings as appropriate to all materials regardless of imprint date.
Medical titles generally are classified according to the National Library of Medicine Classification available online at http://wwwcf.nlm.nih.gov/class/ (see also Classification and Shelflisting).
For titles in fields peripheral to medicine, the Library of Congress classification schedules are used in full, with no modification.
Various substitutes for traditional call numbers are used in cataloging:
1. Since 1994, an accession shelving number has been used in addition to an NLM or LC classification number for the call number of records for print monographs shelved in the general collection at NLM. Prior to that time, only a fully shelflisted call number based on NLM or LC classification was provided, except in the case of limited cataloging (see number 4, below).
2. An alphanumeric shelving number is used instead of an NLM or LC classification number for the call number of limited cataloging records for materials cataloged prior to 1994.
3. An alternative call number without cuttering or date is provided for monographic titles shelved in the general collection at NLM. Limited level cataloging records cataloged prior to summer 1988 were not assigned alternative call numbers. Full and core level records cataloged prior to June 21, 2010 have fully shelflisted alternative call numbers.
4. Serials are classified in the form number W1 with the exceptions of: Government administrative reports or statistics (W2), hospital administrative reports or statistics (WX 2), certain publication types, e.g., directories (monographic form numbers), and bibliographies and indexes (Z).
Before July 1988, the W3 classification number was assigned to sequentially numbered or dated monographic conferences. These congresses are now classed in the appropriate subject classification. Reports or proceedings of congresses published as serials are classified in W1 with other serials.
NLM classes serial analytics with the serial call number. W1 and W3 serial analytics cataloged since the mid 1970s also carry an alternative subject call number provided by NLM for libraries wishing to class such publications by subject.
5. Since 2004, an audiovisual accession shelving number has been used for non-print materials shelved in the general collection at NLM. An alternative NLM or LC classification number is provided without a cutter number or date.