Browsing through Public Access Catalogs.
Jamshid Beheshti · Information Technology and Libraries · 1992
Browsing is an important aspect of the information-seeking activities of library and is primarily visual. Second-generation OPACs lack lack necessary visual characteristics for browsing. These characteristics may be best implemented through simulation of images of books and library shelves on the computer monitors. To mimic users mental models of the real world may be costly, however, unless new interfaces can tap into existing sources of information. A possible solution may be found in using the information embedded in the MARC record pertaining to the physical description of a book. Public Access Catalog Extension (PACE) is designed as an alternative interface based on mental images of and MARC records. In the 1960s MARC was introduced to the library world; in the 1970s automated cataloging systems were developed; and in the 1980s came the introduction of online public access catalogs (OPACs). As each decade passed, sophisticated systems were produced and implemented to automate library functions and to provide end with more efficient and effective services. Today, automated systems are used extensively in different information environments and online catalogs have had overwhelming acceptance by the public, replacing the more traditional card catalogs. (1) OPACs have evolved from the first to the second generation, enabling to search through keywords in a variety of fields using Boolean logic, truncation, and proximity operators. In addition, many second-generation systems enable end to have access to two or more search modes, such as menus and commands, and several display options. These OPACs, however, are different from commercial databases available through systems such as DIALOG and BRS in several respects. They are primarily designed for end users. They do not have extensive descriptors, abstracts, or many other accessible fields as traditional online bibliographical databases do. Furthermore, they cover a variety of subjects and are not confined to a particular discipline. (2) Traditionally, OPACs have involved mini or mainframe computers in a multi-user environment. With the introduction of CD-ROMs, a new generation of online catalogs, sometimes referred to as PACs (public access catalogs), has emerged in the market. PACs have been associated with single-user computing, but some may be used in a network environment. The distinction between the two categories of online catalogs has become blurry; one CD-ROM vendor reports that its largest system serves over 250 stations and includes two million records. (3) Using the microcomputer's graphic capabilities, user interfaces of CD-ROM PACs are generally more friendly than OPACs, with such features as help windows and pull-down menus. Despite their sophisticated retrieval engines, research shows have a number of problems in interacting with OPACs. An in-depth analysis of these problems may be found in a recent article by Martha M. Yee, who has reviewed over 150 studies in this area. (4) Yee summarizes the obstacles facing of OPACs as: finding appropriate subject terms, large number of hits and failure to reduce the retrieval sets, zero hits and failure to increase the retrieval sets, failure to understand cataloging rules, and spelling and typographical errors. In addition, lack of understanding of the indexes, files, and the basic database structure has led to the use of articles, stop words, inputting author's first name before the last name, and hyphenation problems. Interfaces and retrieval systems have caused a few problems of their own--namely, complex interfaces and the need for training and relearning when used infrequently, incomprehensible error messages, problems associated with displays both for brief records and for complete cataloging information, incomprehensible HELP messages, and predicaments of Boolean logic. These problems have prompted one researcher to state that the second-generation OPACs, like many other online retrieval systems, are powerful and efficient but are dumb, passive systems which require resourceful, active, intelligent human searchers to produce acceptable results. …