Library of Congress Subject Headings

Library of Congress Subject Headings Lecture 1

Purpose of Subject Headings • Provide additional access to the work via the subject content • Bring together in the catalog items on the same subject using the same terminology • Provide a formal description of the subject content of any bibliographic unit in the most precise terms possible Growing petunias in Poughkeepsie Cyberterrorism, electronic warfare… Guppies

Cataloging a book on Koi 245 04 |a The essential book of koi / … 650 _0 |a Koi. Subject heading: Koi

Specificity of heading 245 04 |a The essential book of koi / … 650 _0 |a Koi. 650 _0 |a Fishes.

Indexing The process of analyzing a bibliographic entity and creating entries for it, especially subject entries, in an index.

Subject cataloging – two main steps • Conceptual analysis - decide what the book is about • Translation - conversion of the conceptual analysis into a particular set of authorized terms

Lists of authorized terms • Library of Congress Subject Headings (LCSH) • Subject headings for children (used in conjunction with LCSH) • Sears List of Subject Headings • Medical Subject Headings (MeSH)

Controlled vocabulary Authorized Terms Books Alligators Asparagus Bananas Bears Corn

Problem: Ambiguity Books Term ? Faults

Specify single meaning per term Authorized term Books Faults (Geology)

Problem: Synonyms Books on UFOs Authors’ Terms Flying saucers Unidentified flying objects Alien spacecraft

Single authorized term per subject Books Authorized term Unidentified flying objects Flying saucers See Unidentified flying objects

Controlled vocabulary (1) • Restricted to authorized terms • Increases precision — fewer "false drops" • Out-performs keyword searches

Controlled vocabulary (2) • Expensive — requires human knowledge

Controlled vocabulary (3) • Implemented in two ways: • Pre-coordinate indexing • Post-coordinate indexing

Pre-coordinate subject heading Examples: String built at time of indexing using the rules of the indexing language Railroads—Right of way—Massachusetts Children as inventors

Post-coordinate descriptors Terms put together at time of retrieval Railroads Railroads Right of way AND Right of way Massachusetts AND Massachusetts Children AND Inventors

Pre-Coordinate Indexing (1) • Indexing using terms that are chosen and coordinated at the time of indexing • Usually a person trained in indexing assigns the terms • Can be one term or a combination of terms but they are pre-determined (i.e., they are “authority controlled”)

Pre-Coordinate Indexing (2) • Older; associated with books • Associated with card catalogs • Usually referred to as subject headings • Examples: • Children as air pilots • Humor in education

Advantages of Pre-Coordinate Indexing (1) • Consistency - we all use the same terms to mean the same things • More precise - we can obtain things specifically about our topic

Advantages of Pre-Coordinate Indexing (2) • Prevents false drops - because the phrase has been constructed in a manner that has a specific meaning • Children as inventors would obtain works dealing with children in the role of inventors rather than inventors creating objects for children

Disadvantages of Pre-coordinate Indexing (1) • Assumes that users know the indexing language--both its vocabulary and syntax. • Everyone has to use the same term; if I don't know the predetermined term or if I have a different perception of the same thing then I may not find the item.

Disadvantages of Pre-coordinate Indexing (2) • Some systems will not allow user to search on subordinate term For example, if you have: Seeds—Cleaning—Equipment and supplies The system may not allow you to search on equipment and supplies and find this subject heading

Searching for subject heading France—History—Revolution, 1789-1799—Art and the Revolution—Catalogs.

Post-Coordinate Indexing (1) • Coordination takes place at time of retrieval • Example would be ERIC descriptors • Newer; associated with documents

Eric descriptors Profiles; Cognitive Ability; Gifted; Cognitive Development; Bilingualism; Monolingualism; Socioeconomic Status; Quasiexperimental Design; Children; Hispanic Americans; Measures (Individuals); Cultural Influences

Post-Coordinate Indexing (2) • Associated with computers and Boolean logic • Usually referred to as descriptors • Examples: • Children • Gifted • Foreign countries

Gifted children in China gifted children china

Gifted children in China Gifted children—China Gifted children—China—Anecdotes Gifted children—China—Biography

Gifted children in China

Gifted children in China gifted children china

Gifted children in China No results were found.

Gifted children in China gifted children foreign countries

Gifted children in China 97

Gifted children in China Intelligence, Gifted, Brain, Children, Comparative Analysis, Foreign Countries

Advantages of Post-coordinated Indexing • Allowed the freedom to combine authorized terms that are relevant • Can do Boolean logic

Disadvantage of Post-Coordinated Indexing • Lack of precision: Few items really can be described by a single descriptor; most searches involve Boolean logic, truncation, etc. These techniques, while powerful, result in obtaining things we don't want (e.g., childrenANDinventors will retrieve items about people who invent things for children as well as children as inventors).

In general… Post-coordinated indexing increases recall (retrieves more items) but decreases precision. If both the indexer and the searcher know the indexing language, and both do their jobs well, then pre-coordinate indexing will do as well as or better than post-coordinate indexing.

Cutter's Rules for a Dictionary Catalog (1) Published 1904 • The reader as focus: Use terms that the user uses Housefly Musca domestica

Cutter's Rules for a Dictionary Catalog (2) Published 1904 • Unity • Objective is to unite all the books about a specific subject under one heading

Cutter's Rules for a Dictionary Catalog (3) • Usage Common usage (determined by literary mandate) What happened in Hawai`i in 1893? Old term: Hawaii—History—Revolution of 1893 New term: Hawaii—History—Overthrow of the monarchy, 1893

Cutter's Rules for a Dictionary Catalog (4) • Specificity • The terms should be as specific as possible (e.g. Calico cats) • In applying headings, rather than using broader subject heading use 2 specific headings if apply • Rule of 3: If more than 3 related subject headings use the broader term (e.g., 4 dog breeds)

Library of Congress Subject Headings • Established ~1898* • Adopted by many libraries around the world • Now published annually • Now five volumes • Referred to as LCSH or “The Big Red Books” • Subject authority records available online *or 1902 or 1909

Types of LCSH headings • Single nouns • Two word headings • Adjectival headings • Conjunctive headings • Prepositional headings • Glossed headings • Proper nouns

Library of Congress Subject Headings