In order to effectively use periodical indexes to find articles or to use a library catalog to find books (and, in some cases, to use indexes in encyclopedias and other reference books), you should first translate your preliminary research topic or research question into useful words and phrases-- often referred to as "search terms". Using the right search terms enables you to efficiently access the books and articles which most specifically address your topic. The process of identifying search terms for a topic is often referred to by library researchers as developing "vocabulary control." This process actually begins when you first start to select your topic and continues throughout the entire research process. It is usually helpful to identify a variety of search terms relevant to the topic-- synonymous, related, broader and narrower. Different "access tools"-- catalogs and various periodical indexes-- commonly use different terms for the same topic.

Subject headings and descriptors are two slightly different types of formally-designated search terms. Subject headings are used by catalogs and many of the more popular periodical indexes. Each book in a catalog or each article in an index is usually assigned just a few subject headings. Subject headings tend to be relatively broad in scope and are often subdivided for more specificity. Descriptors tend to be more limited in scope than subject headings and are commonly used in more specialized or academic periodical indexes. More descriptors are typically listed for each article, often referring to specific concepts within an article. This enables various combinations of descriptors to be used to more precisely identify articles on a specific topic.

When you first have an idea for a topic, you generally have a word or words that you use to describe the idea. In a sense, these are your first informal search terms. If you use an encyclopedia to try to focus in on a topic or to find background information on a topic, the index to the encyclopedia may help you to begin to come up with a list of relevant search terms. In addition to encyclopedias, other reference tools, such as general and subject-oriented dictionaries or guides to the literature in various subject areas, may give you ideas for other search terms.

Once you have some initial search terms for your topic, you can try some preliminary searches in periodical indexes or a library catalog. If you have already come up with a relatively specific topic, try to find words that identify your topic as precisely as possible. Start searching with the most specific words you can think of. If you don't find anything with your most specific words, try using slightly broader terms until you are able to find some information. If you are not yet sure of a specific research topic, start with broader terms and then try to find ideas to focus on as you begin to find information.

As soon as you find a record for an article or book that is related to your topic, check to see what subject headings have been assigned to that record. This can be an excellent strategy for finding subject headings that are most related to your topic. You can then use those headings to find additional articles or books on your topic. (This process is explained in more detail below under "Tracings")

As you use each of the different research tools, you will probably be able to find additional relevant search terms which, in turn, may provide you with additional sources of information on your topic. Finding appropriate search terms in any of these types of research tools can sometimes seem like detective work, but there are various useful strategies common to all of these tools that can help you identify the most relevant search terms quite efficiently.

What are Subject Headings?

When you begin to look for information on a topic in catalogs, periodical indexes or reference books, it is often not obvious which word or words to use for your particular topic. The official words used by catalogs and many indexes to identify all of the books or articles dealing with a particular topic are called subject headings. Subject headings can be one word, two or more words, a phrase, a city, a country, a person, etc. For example, the following are all subject headings:








Obvious and Less Obvious

Subject headings can sometimes be the words that first come to mind for a topic. Books or articles on CHILDREN'S LITERATURE and PHOTOGRAPHY, for example, may be found under these same headings. Notice that subjects are generally listed in plural form, when possible. For example, SHARKS is used rather than SHARK, and APARTMENT HOUSES not APARTMENT HOUSE.

On the other hand, subject headings may be expressed in less obvious terms. For example, you may look up the subject MOVIES in a catalog or index and find nothing. Then you try FILMS-- again, no luck. You might assume that there is no information listed on this subject. There are, in fact, many books and articles on movies-- under the subject heading: MOTION PICTURES.

Some other examples of topics with subject headings you probably wouldn't expect:


Subject Heading

Finding a job


The American Revolution


Medieval art


Reverse the Order: Inverted Headings

Sometimes, a subject heading is inverted to emphasize the more important words. In such cases, you can figure out the correct subject heading by just reversing the words you first think of. For example, the subject heading for information on abstract art is ART, ABSTRACT. For American authors, the subject heading is AUTHORS, AMERICAN. These are referred to as "inverted headings."


Subheadings or Subdivisions

Since subject headings often cover relatively broad concepts, subheadings (more formally referred to as subdivisions) are commonly used to designate a more specific aspect of the subject. The use of subheadings is a very important method of focusing in on, or refining, a topic. For example, the subject heading for information on the social aspects of the mass media is MASS MEDIA--SOCIAL ASPECTS, or for information on Chinese history, the subject heading to use would be CHINA--HISTORY. A dash (--) is always used to designate a subheading. Four types of subheadings are commonly used in many subject headings.


Types of Subheadings

Topical subheadings narrow the subject to a particular aspect of the subject such as MASS MEDIA--SOCIAL ASPECTS. There are various topical subheadings that are commonly used with different main headings. Some examples include: --LAW AND LEGISLATION; --MORAL AND ETHICAL ASPECTS; --POLITICAL ASPECTS; --PSYCHOLOGICAL ASPECTS; --SOCIAL ASPECTS; STUDY AND TEACHING and VOCATIONAL GUIDANCE. When the main subject heading is a country, some regularly-used subheadings include: --ANTIQUITIES; --DESCRIPTION AND TRAVEL; --ECONOMIC CONDITIONS; --FOREIGN RELATIONS; --HISTORY; --POLITICS AND GOVERNMENT; --SOCIAL CONDITIONS; and --SOCIAL LIFE AND CUSTOMS.

Geographical subheadings narrow the subject to a particular geographical area, such as a country, state or city. For example: MASS MEDIA--UNITED STATES.

Form subheadings specifiy a particular type or form of publication such as MASS MEDIA--DICTIONARIES or MASS MEDIA--COLLECTED WORKS. Some other commonly-used form subheadings include: --ADDRESSES, ESSAYS, LECTURES; --BIBLIOGRAPHY; --SOURCES; --COLLECTED WORKS; CONGRESSES; --HANDBOOKS, MANUALS, ETC; --FICTION.

Chronological subheadings narrow the subject to a particular date or time period. Chronological subheadings are commonly used when dealing with historical subjects. When searching for information on any aspect of American history, for example, always start with U.S.--HISTORY and then add a chronological subheading such as UNITED STATES--HISTORY--19TH CENTURY or UNITED STATES--HISTORY--1865-1877. (Another example is the subject heading listed above for the American Revolution: UNITED STATES--HISTORY--REVOLUTION.) Chronological subheadings are organized in chronological order, not in alphabetical order. For example:





More than one subheading may be used in a single subject heading and different types of subheadings are commonly used in these cases, for example: MASS MEDIA--SOCIAL ASPECTS--UNITED STATES--COLLECTED WORKS. Notice that adding additional subheadings makes the subject heading more precise. For information on the topic of traveling in Mexico, a subject heading might be: "MEXICO--DESCRIPTION AND TRAVEL." To narrow down the topic to the question: "How to stay healthy while traveling in Mexico?", a more specific subject heading would be: "MEXICO--DESCRIPTION AND TRAVEL--HEALTH ASPECTS."


Cross References

Since subject headings for many topics are often not the words commonly expected, most indexes and catalogs include cross references--"See" references and "See also" references-- to help you find the right subject headings for the topic you are interested in. There are significant differences between these two types of references and it is important to understand the proper function of each.


"See" references

"See" references tell you that the word you are using to look up your subject is not the correct word that is used in the catalog or index. Instead, another word is given under which you should look up the subject. For example, if you look for books or articles on the subject of the death penalty, you will probably find the following reference:


This "See" reference tells you that to find information on the topic of the death penalty, you must look under the subject heading, CAPITAL PUNISHMENT.


"See also" references

"See also" references tell you that the word you are using to look up your subject is the correct subject heading, but it suggests that you can also find additional books or articles related to your topic under other subject headings as well as the subject heading in which you are currently looking. For example, if you look for information on the subject of computers, you might find the following reference:


See Also





This "See also" reference tells you that you will find information under the subject heading, COMPUTERS, but you will also be able to find other information related to computers if you look under the other subject headings shown (COMPUTER ART, ELECTRONIC DATA PROCESSING, ELECTRONIC DIGITAL COMPUTERS and INFORMATION STORAGE AND RETRIEVAL SYSTEMS.)

Tracings: Subject Headings Listed in a Record

When you find some initial books or articles on your topic in a library catalog or in many periodical indexes, the records for those items can lead you to additional subject headings for the topic. In most databases, each record contains a list of all subject headings or descriptors under which the record is listed. In online catalogs, additional subject headings-- called "tracings"-- are usually included in the full record display. The full record in which the tracings are shown is not usually the standard information displayed in most computerized catalogs and periodical indexes. When the tracings are not shown in the standard display for a record, there is usually a simple command that can be entered to display the full record, including the tracings. In the PLS online catalog, for example, the brief record displays the main bibliographic information--author, title, publisher, publication date, etc.--and the call number for a book. Print periodical indexes vary as to whether additional headings are listed--general interest periodical indexes (such as Readers' Guide or Humanities Index) usually do not list additional headings while more specialized academic indexes (such as Psychological Abstracts or Historical Abstracts) typically do include additional descriptors in each record.

Notice from the catalog entry below that this book is classified under four subject headings: WOMEN--PSYCHOLOGY, SOCIALIZATION, SUCCESS and ABILITY. By looking under any of these subject headings, you would be likely to find other books on topics that are in some way related to this book.

Author: Barnett, Rosalind C.

Title: The competent woman: perspectives on development/ by Rosalind C. Barnett and Grace K. Baruch ;

Publisher: New York : Wiley : distributed by Halsted Press, c1978.

Description: 184 p.; 22 cm.

Notes: Includes index.

Bibliography: Bibliography: p.[158]-174


Added author:

Baruch, Grace K., joint author.

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last revised: 2-1-00 by Eric Brenner, Skyline College, San Bruno, CA

These materials may be used for educational purposes if you inform and credit the author and cite the source as: LSCI 105 Online Research. All commercial rights are reserved. To contact the author, send comments or suggestions to: Eric Brenner at