The University of Kansas Libraries
Subject Headings & Controlled Vocabulary
Subject headings provide one of the primary search techniques you may use in retrieving information from resources in the KU Libraries. They may be used in both print and electronic sources. The strength of subject headings (often called descriptors) is that they allow us to use a controlled vocabulary to organize information in a logical fashion. The goal is to make it easier for you to find the specific information you need.
Controlled vocabulary is a set of standard terms used to describe the contents of items found in a database. This includes the contents of books in the library and articles listed in an index. A term in a controlled vocabulary may describe a person, an event, an idea, or a place.
In libraries controlled vocabulary is generally referred to as subject headings. The KU Libraries, in common with most academic libraries, use the Library of Congress Subject Headings to describe the content of its book collection. Most of the records for books you will find in the library's online catalog have one or more subject headings attached to them. Periodical indexes often refer to their controlled vocabulary terms as descriptors or a thesaurus, but it all means the same thing.
Controlled vocabulary is an important way of drawing together under a single word or phrase, all the material that is available on a particular topic. The purpose is to take the "guess work" out of searching. We tend to have many different ways of describing the same concept. For example, let's say you're trying to find all the information you can in the library on the topic ofthe Civil War. What term would you use to search? Civil War? There have been a lot of those in many different countries. American Civil War? U.S. Civil War? United States Civil War? Civil War in the United States? War Between the States? War of Secession? War of the Rebellion? The Lost Cause? The choices are almost endless.
Does that mean you have to think up all these different synonymous terms in order to find everything you can on the topic? Not if you use controlled vocabulary. For example, if you look up the term American Civil War in the Library of Congress Subject Headings you find that the subject heading to use is United States -- History -- Civil War, 1861-1865. That may seem a rather awkward or ponderous term to search, but using it will show you a list of many of the books the KU Libraries has on the Civil War in a single search!
By drawing together all items on the same topic under a single word or phrase, controlled vocabulary can make searching for information much easier.
This is only a very brief introduction to the essentials of subject headings. If you need to conduct more sophisticated searches or have any problems or questions, please ask one of the librarians working at the Reference Desk for assistance.