02 - “VIETNAM” In Library Of Congress Subject Headings

 

Thomas Mann

Library of Congress

 

 The virtues of Library of Congress Subject Headings (LCSH) over simple keyword searching are several. These search advantages are well exemplified in regard to "Vietnam" as a topic of investigation.

Unlike keyword searching, which simply gives the reader "something," LCSH provides a structured overview of a wide range of options relevant to the topic. It does this through collocation of terms within the basic LCSH list itself (often referred to as "the red books"), through cross-referencing, and through browse displays within online catalogs. The formal headings and cross-references starting with the terms Vietnam or Vietnamese extend over three full pages in the LCSH list. A searcher interested in the history of Vietnam, for example, would find Vietnam--History listed as a category, of course; but she would also be enabled to notice a wide range of other headings that are also relevant, but that do not include the word "History," such as the following:

 Vietnam

-         Antiquities

-         Civilization

-         Buddhist influence

-         Chinese influence

-         European influence

-         Indic influence

-         Western influence

-         Description and travel 

-         Intellectual life

-         Politics and government

-         1858-1945

-         20th century

-         1945-1975 

-         1975- 

-         Vietnamese conflict, 1961-1975

-         Vietnamese diaries

-         Vietnamese literature

-         Vietnamese reunification question (1954-1976)

All of these aspects of Vietnam's history would be missed by a keyword search of "Vietnam" AND "History."

Even within the category Vietnam--History, LCSH displays a structured overview of options that would not be apparent to a keyword searcher: 

Vietnam

-         History 

               -         To 939

-         Ba To Uprising, 1945

-         Trung Sisters--Rebellion, 39-43

-         939-1428

-         Dinh dynasty, 968-980

-         Early Le dynasty, 980-1009

-         Ly dynasty, 1010-1225

-         Tran dynasty, 1225-1400

-         Ho dynasty, 1400-1407

-         Lam Son Uprising, 1418-1428

-         Later Le dynasty, 1428-1787

-         Mac dynasty, 1527-1592

-         Insurrection, 1771-1802

-         1787-1858

-         Tay Son dynasty, 1788-1802

-         19th century

-         Nguyen dynasty, 1802-1945

-         Le Van Khoi's Rebellion, 1833-1835

-         1858-1945

-         Truong Dinh Uprising, 1862-1864

-         Bay Thua Uprising, 1867-1873

-         Yen The Uprising, 1884-1913

-         20th century

-         August revolution, 1945

-         1945-1975 

-         1975-

-         Prophecies

 The amplitude of such an array serves to bring to researchers' attention whole arrays of options that they probably will not know, in advance, to exist; it will also enable researchers to focus their inquiries, quickly, on only topics relevant to their particular interest within the history of Vietnam, without having to wade through mountains of more general, or simply irrelevant, sources. Readers are enabled to simply recognize relevant search options that they could never specify in advance in keyword searching. They are also enabled to see, even before retrieving any individual books, a kind of structural overview of the main aspects of Vietnam's history. (Just from the number of uprisings and rebellions listed, a researcher could readily conclude right off the bat that the Vietnamese people will not long tolerate unjust oppressions.)

The amplitude of this initial structured display of research options is greatly extended by an extensive network of cross-references to other relevant headings that do not even mention, or include, the keyword "Vietnam--." For example, under the heading Vietnam--Languages the researcher would be led to many more specific topics that he or she could probably not specify in advance:

 Vietnam

 -         Languages

                   NT Bahnaric

-         Biat language

-         Bru language

-         Central Muong language

-         Chamic languages

-         Eastern Mnong language

-         Hre language

-         Kadai languages

-         Koho languages

-         Laha language (Vietnam)

-         Laqua language

-         Maa dialect (Vietnam)

-         Maa language (Southeastern Asia)

-         Nguon language

-         Northern Roglai dialect

-         Puoc language

-         Rade language

-         Rengao language

-         Roglai language

-         Ruc language

-         Sre dialect

-         Yay language

 Again, just from an initial look at the list of these languages and dialects, and before retrieving even a single actual book, a researcher could readily conclude that Vietnamese culture is more diverse than monolithic. And, again, these terms do not generally include the word "Vietnam," and so would be overlooked by a keyword search of "Vietnam" AND "Language--." The Library of Congress Subject Headings list, however, brings these options to people's attention even when the researchers were not asking for them. This is something that scholars always greatly appreciate: a mechanism that prevents them from overlooking important options because they didn't know which questions to ask in the first place.

The important overview provided by LCSH is further extended, beyond the "red books" list itself, by browse displays in online computer catalogs. The LCSH list itself, for example, records Vietnam--Antiquities as a heading, but gives no further search options within that category. The online catalog, however--depending on the holdings of the particular library--provides an even more extensive overview:

 Vietnam -- Antiquities

             Vietnam -- Antiquities -- Bibliography

             Vietnam -- Antiquities -- Dictionaries

             Vietnam -- Antiquities -- Exhibitions

             Vietnam -- Antiquities -- Periodicals 

In fact, most of the subdivisions of a topic that are spelled out in an online catalog's browse display are not recorded within the LCSH thesaurus itself. This is because most subdivisions are "free floaters"--which means that they can be assigned as needed by catalogers, but without the attachment being recorded in the LCSH list itself. In other words, the range of category options possible

within the LCSH system is not exhausted only by the "red books" thesaurus alone; the online catalog that uses LCSH will inevitably show researchers even more possibilities.

Most researchers who approach a new topic do not already know in advance exactly what they want or need to find; nor do they know in advance the extent of the vocabulary appropriate to a new subject area. The virtue of the Library of Congress Subject Headings system is that it solves just these problems. It lays out structured displays of options that show people more than they are capable of asking for. It provides scholars with a large range of options available to be searched within a topic, so that beginning inquirers can simply recognize relevant possibilities that they could never specify beforehand in keyword searching. Such a structured search enables researchers to be more systematic, extensive, and focused in their initial, exploratory inquiries, without having to have prior subject expertise in the area of their investigation. Those who learn how to use the LCSH subject heading system will be much more efficient researchers than those who simply rely on keyword searching.

 

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Thomas Mann is a reference librarian in the Main Reading Room of the Library of Congress.  He is the author of The Oxford Guide to Library Research (Oxford U. Press, 1998) and Library Research Models (Oxford, 1992).