Identical in Appearance but Not in Actuality: Headings Shared by a Subject-Access and a Form/Genre Access Authority List

Abstract

Authority records were compared for established headings that are identical in Library of Congress Subject Headings (LCSH, 18th edition) and Moving-Image Materials: Genre Terms (MIM). First, the Use For, Broader Term, Narrower Term, and Related Term references in the LCSH authority file were compared with their counterparts in MIM, to determine the proportion of duplication existing between them. Fewer than 10% of these reference headings are identical. Second, a qualitative comparison was made of the “semantic spaces” inhabited by identical headings in different contexts: a general-purpose subject access list as compared with a medium-specific form/genre access list. It was found that, in many cases, headings that are identical as character strings have markedly different meanings in different contexts. The conclusion offered is that, both quantitatively and qualitatively, pairs of identical headings differ sufficiently from each other that the creation of authority records for each usage represents no duplication in any meaningful sense. The striking divergence, in many instances, between semantic spaces provides food for thought on the differences between the naming of subjects and of forms/genres.