How Useful are Library of Congress Subject Headings?

by Moya K. Mason


There are three things to consider when addressing the bibliographic control of libraries: physical control, intellectual control, and information retrieval. Physical control is the organization of the collection through a classification scheme, which allows for the development of shelf and inventory lists, and gives browsing access to library users. Intellectual control provides information about the content of any book, in a universally-accepted and standard manner, and is achieved through cataloguing and indexing. Independently, both are integral components of bibliographic control in modern libraries, but it is good information retrieval that makes public access to the world of knowledge possible, and is, therefore, of primary importance.

Online information retrieval practices vary from author and title searches, to access through call number, keyword subject, and subject heading indexes in Public Access Catalogues. Depending upon the information available and the research needs, one route will often be more beneficial than another. If an author or title is the goal of a search, it doesn't matter, but what if these are unknown and the research process must begin solely with the subject? This essay will explore how the Library of Congress Subject Headings function to provide access to various aspects of topics in general, and in particular, 20th Century Architecture and its related topics. In addition, it will endeavour to present some of the advantages and disadvantages of LCSH in the online environment by providing the results collected from subject heading searching and keyword searching for the topic of 20th Century Architecture, and by explaining how the words option relates to controlled vocabulary. To begin, a brief explanation of LC Subject Headings will prove useful as a foundation for the discussion.

An Overview of LCSH

In 1897, the Library of Congress moved into its new building; it was decided that a new and improved classification system was in order, as well as the development of an alphabetically-arranged main catalogue for author names, titles, and subject headings (Chan 1986,4). Both the LC Classification scheme and its subject headings were built upon terms of literary warrant. Lois Mai Chan points out that:

The subject heading's list was developed in especially close connection with the Library's collection. It was not conceived at the outset as, nor has it ever been intended to be, a comprehensive system covering the universe of knowledge (Chan 1986,10).

As a result, it is important to remember that subject headings are not devised in any logical all-encompassing fashion, but rather, are added as new acquisitions warrant them, with approximately eight thousand headings added per year (LCSH 1988,x). They may be supplemented with scope notes that specify distinctions between related subjects and also give subjects their range. All are listed in boldface type and may be followed by LC class numbers or a bracketed italicized code that permits subdivision by place. Since the dual purpose of subject headings is to enable users' access to information on any subject and to provide material on related topics (Wynar 1985,449), it is no surprise that the use of cross-references have always been important. Over the years, these have changed and presently reflect an emphasis on hierarchical order (LCSH 1988,xii). Some of the standard codes now used for cross-referencing in LCSH are NT (Narrower Term), BT (Broader Term), RT (Related Term), UF (Used For), and USE, which directs users to preferred terminology. NTs and BTs form links to other subject headings and allow for hierarchical ordering, while RTs "link two terms that are associated in some manner other than hierarchy" (LCSH 1988,xi).

Subject headings in LC extensively use subdivisions to bring together a number of different concepts under one heading (Chan 1986,64). LCSH has four main categories of subdivisions: topical, form, chronological, and geographic; each follows a set of guidelines (Chan 1986,65). Overall, there is an inexhaustible combination of headings and subdivisions that are divided by a long dash, with further dashes representing further subdivisions. Many can be found in print form in the Manual, while others, called free-floating subdivisions, are constructed with rules rather than submitted and authorized (LCSH 1988,ix). In general, it can be said that subject headings act as access points to bibliographic records, and since the late 1970s, have been the indexing vocabulary for the MARC database (Chan 1986,3). Consequently, subject headings are major tools for online information retrieval.

An Overview of 20th Century Architecture Within LCSH

Subject headings are controlled vocabularies for library catalogues and allow the subject content of works to be researched. They are chosen by cataloguers for each specific work, with two to three headings used on average. The most powerful characteristic of subject headings are their subdivisions because they bring out aspects of a topic that may not be fully represented by the first heading. For example, 20th Century Architecture (a chronological subdivision that can, in turn, be subdivided by place) is found as a subdivision of Architecture, Modern, and its synthetic structure or cross- references are crucial for in-depth research on the topic. In this case, the LCSH Narrower Terms are numerous and form an excellent schedule of sub-topics and areas of related interest that are helpful in researching both the core areas of the subject, and the finer details. By way of illustrating this point, a descriptive overview of the individual cross-references of 20th Century architecture in LCSH will follow.

Edwardian Architecture focuses on the Modern architectural movement in England, and could have been placed lower in the list under the geographic subdivisions. Postmodern Architecture represents the kind of design work that followed the modernistic period, as its utopian expectations waned and a yearning for traditional methods grew. Art Deco arose out of a desire to reduce the gaudy influences and trends of the Art Nouveau style, an influential movement in Modern Architecture, but missing from the LCSH. Brutalism in architecture was inspired by Le Corbusier and his precedent setting work with concrete. It was especially popular in England, whereas Constructivism was by and large, a Russian movement that epitomized the functionalism that the newly born USSR advocated.

The subdivision of Eclecticism in architecture was significant because, in many ways, it caused the explosion of Modernism in the 20th Century. Its continual manipulation of ancient Greek and Roman architecture, and its degeneration into revivalist styles drove architects such as Frank Lloyd Wright into action. Functionalism in Architecture was the general movement away from ornamentation in design and affected the International Style, which was a major architectural trend early in the 20th Century that made use of concrete, glass, and steel and contributed to the design of the skyscraper. Shaped by the Constructivists and the teachings of Bauhaus, it emphasized function and advocation of industrial building techniques. Bauhaus is another fundamental segment of 20th Century architecture, and it warrants its own distinct subdivision in LCSH. Megastructures, Organic architecture, and Romanesque revival architecture are the final three subdivisions and will be discussed in their geographic cross-references.

As stated earlier, 20th Century Modern Architecture can be subdivided by any place name, and six such sub-topics were found, however, if a library has books on this subject that do not fall under the given geographic subdivisions, it will simply develop its own. For example, the University of Western Ontario's D.B. Weldon Library has many books on 20th Century Architecture in The Netherlands, and therefore, has created its own additional subject headings to reflect the collection. Subject headings are controlled vocabularies, but the Library of Congress has made provisions for collections other than their own. Under Illinois, the NT of Chicago Seven (Group of Architects) is listed, giving direction to the American movement with Louis Sullivan, famous in his own right, and mentor to 20th Century's gifted architect, Frank Lloyd Wright.

The sub-topic of Japan is a cross reference for Megastructures and Metabolism in Japanese modern architecture, while Middle West's Prairie School relates back to Sullivan and Wright. The Soviet Union has the NT of Socialist realism, and the United States has NTs of Mission style and Usonian houses that refer to Organic architecture and Wright's Fallingwater House and Hanna House. The final sub-topic is Chinese Influences, with the BT of China-Civilization, which may be helpful for research. By this series of excellent subdivisions and sub-topics, LCSH manages to cover the topic area of 20th Century Architecture extremely well, including some interesting related areas. LCSH does so in an in-depth manner, using good cross-references. What the subject headings have actually done is to provide an excellent starting point for research into the area. How does it work in the online environment?

LCSH Online

The search of 20th Century Modern Architecture gave some very interesting results. Using the subject search, 124 subjects were given that had 440 entries. The first entry supplied a See Related Subjects note, which provided all the NTs found in the printed directory and discussed earlier. The remainder identified the topic with geographic subdivisions ranging from Alberta, Australia, British Columbia, California, Canada, and Europe, and all the way down the list to Mexico, New York, Ontario, Scotland, and finally, Washington. Since individual works have their subject headings presented in the online catalogue, additional directions for research can be found in them. The search supplied a manageable number of subjects and entries to sift through quite quickly. There was more than enough good information on the subject for research purposes, because subject searching is controlled vocabulary that uses precoordinate words and phrases that with proper use, help in avoiding and reducing false drops. As far as this topic is concerned, the online subject headings were more beneficial, because they offered many more possibilities for specialized research. This differs dramatically from keyword searching, which uses free text or natural language, and is in direct opposition to intellectually-controlled vocabulary.

Online keyword searching uses the words option of the UWO catalogue. Since keyword searching scans the entire MARC RECORD, there is an abundance of irrelevant information retrieved. In the case of 20th Century Architecture, 532 entries were found, which is an overwhelming number to go through, and a time- consuming proposition. The major problem is that keyword searching does not give users good starting points for research. It puts everything together, with no direction. For example, if the goal was 20th Century Canadian Architecture, a subject search allows quick access to relevant material and includes books on one of Canada's great architects, Douglas Cardinal. What if the researcher is not aware that Cardinal, or Safdie, or Erickson are Canadian architects? Searching using keywords is not going to prove very helpful, because those books will be overlooked quite easily. There is too much information not organized into subdivisions to consider keyword searching as effective as subject searching.

Concluding Remarks

Subject headings can bring out what a book is really about and does more than the title or table of contents can. It is a very powerful tool for information retrieval, even with its inherent problems associated with having to accept pre-coordinate phrases that are sometimes difficult to remember. Additional complications of terminology dilemmas, uniformity of headings, need for qualifiers, and inverted headings, exist, among others, but it is still an exceedingly practical tool for serious researchers, especially when compared to the time-consuming and cumbersome activity of keyword searching. An effort should be made by librarians everywhere to advocate its use.

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Reference List

Chan, L.M. 1986. Library of Congress Subject Headings: Principles and Application. Littleton, Co.: Libraries Unlimited.

Library of Congress. 1988. Subject Headings. Washington, D.C.

Wynar, B.S. 1985. Introduction to Cataloguing and Classification, 7th ed. Littleton, Co.: Libraries Unlimited.

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