Library of Congress Subject Headings Pre- vs. Post.pdf

Library of Congress Subject Headings Pre- vs. Post-Coordination and Related Issues Report for Beacher Wiggins, Director, Acquisitions Bibliographic Access Directorate, Library Services, Library of Congress Prepared by the Cataloging Policy and Support Office March 15, 2007 (Approved by ABA Management June 13, 2007, with annotations on Recommendations [p. 9-13] added October 2, 2007, revised December 20, 2007) The Director for Acquisitions and Bibliographic Access at the Library of Congress requested a review of the pros and cons of pre- versus post-coordination of Library of Congress Subject Headings (LCSH). There have been several studies of the pros and cons over the years, most notably by Elaine Svenonius and more recently by Lois Mai Chan and Arlene Taylor/Daniel Joudrey – included as appendices to this report. Briefly stated, pre-coordinated strings provide context, which is needed for “disambiguation, 1 suggestibility, and precision” and browsability. Pre-coordinated strings have a sophisticated syntax that can express concepts better than single words, yet also can be faceted by systems to group topics into categories for post-coordinated displays when desirable. Post-coordinated terms have serious limitations for recall, precision, understanding, and relevance ranking. Rather than review the issue of pre- versus post-coordination, the issue perhaps should be how subject access can best be achieved for users at a cost that reduces the current expense. We know subject access is important to users and a value added service that libraries provide. Additionally, Karen Markey has recently pointed out that subject headings should figure prominently in the post-Boolean probabilistic catalog, as they contrib