Subject authority control in a computerised system: use of CDMARC Subjects in an academic library

Abstract

Authority control is one of the methods designed to maintain the quality and integrity of the catalogue as a bibliographic tool, bringing together the variant forms of the same material, the same author and the same subject. A controlled subject heading structure makes it possible to effect a comprehensive search, as does name authority control, thereby enabling the patron to receive full information about the actual holdings of the library. The paper discusses the planning for and ultimate use of the CD‐MARC Subjects in the Library of the University of Botswana. The Library of Congress Subject Headings (LCSH) is the controlled vocabulary used in assigning subject headings in the Library. The Library realised the desirability to control the subject heading files in the automated system to ensure integrity of the files and opted to do this using the CD‐MARC Subjects. The structure of the records of the CD‐MARC Subjects was mapped to corresponding fields in the thesaurus structure of our system software, TINlib, and made available to our vendor. The thesaurus structure has provision for references and notes associated with subject headings including use, use for (UF), see also broader terms (BT), see also narrower terms (NT), see also related terms (RT), and scope note. Our approach to references that could lead to blind alleys is to print out each 360 field in the database and enter the headings given as examples as thesaurus terms. These terms would automatically have postings assigned to them. The contents of the relevant records in the CD‐MARC Subjects were to be imported as is without change of punctuation pattern. A profile was subsequently written that enables the downloading of terms that are connected to documents in our database. The additional advantage of this is that the thesaurus will not be overloaded with terms that have no documents attached to them. The profile has been tested and a little refinement was found to be necessary. Ultimately, the effort would allow for consistency in subject control, efficiency of search, improved precision and recall, and a reliable database. Our experience should be useful to others anticipating the use of CD‐MARC Subjects or other CDROM‐based authority control tools.