Analysis of a Bibliographic Database Enhanced with a Library Classification
In the Dewey Decimal Classification (DDC) Online Project, the DDC
was studied as a searcher's tool for subject access, browsing, and
display in an experimental online catalog. Subject terms from the DDC
Relative Index and Schedules were added to bibliographic records and
indexed in the catalog. Enhanced with the DDC, the experimental online
catalog offered users additional subject searching strategies not feasible
through the alphabetical approaches of subject headings and keywords
of existing online catalogs. This paper describes how bibliographic
records were enhanced with subject terms from the DDC. Results show that
the DDC was a major contributor of unique, general subject terms to
bibliographic databases. Incorporated in online catalogs, the DDC, and
possibly other library classifications, can enhance subject access and
provide additional subject searching strategies to system users.
ENHANCING SUBJECT ACCESS TO BIBLIOGRAPHIC DATABASES
The importance of incorporating a classification scheme into the information retrieval environment of an online catalog lies in its potential for introducing a logical approach to subject searching and increasing the amount of subject information contained in subject indexes and detailed in bibliographic records. The latter point is the focus of this paper.
Increasing the amount of subject information in bibliographic records and indexes to those records was studied in the Subject Access Project (SAP). Concerned with the dearth of subject information in bibliographic records, SAP investigators added subjects from the tables of contents and indexes of books. They concluded that online searching of enhanced bibliographic records provided greater access to books with relevant information, greater precision, was less costly, and answered some queries that were impossible to answer through keyword searching without the enhancement. A related research project conducted at Lund University Library led to the development of a bibliographic database for the Swedish government in which records were enhanced with subject terms from tables of contents, indexes, figures, and table captions. A review of subject enhancement efforts described additional "SAP-like" research projects and one commercial database (Superindex) with indexing approaches similar to SAP. Staff at two libraries--the Australian Defense Force Academy and the Engineering Library of Purdue University--regularly enhance bibliographic records using the SAP approach; however, data entry of the enhancement is done manually.[4,5] Another review of subject enhancement efforts emphasized that the data needed for such enhancement were not readily available in machine-readable form.
The DDC Online Project provided the opportunity to study the enhancement of a bibliographic database with subject terms from a library classification. The machine-readable DDC used in the DDC Online Project was converted from print tapes, which originally served to produce the 19th edition of the printed DDC using computerized photocomposition. Subject terms from the machine-readable DDC Schedules and Relative Index were automatically assigned to bibliographic records by the computer when the class number of a bibliographic record matched the class number associated with a Schedule caption and/or Relative Index entry. Thus, enhancement of bibliographic records was a computerized procedure and manual data entry was not necessary.
BACKGROUND OF THE DDC ONLINE PROJECT
The DDC Online Project was supported by the Council on Library Resources, OCLC Online Computer Library Center, Inc., and Forest Press (DDC publisher) from 1983 to 1986. The project team developed an experimental online catalog for searching by library patrons and staff in retrieval experiments. …