Classification by Subject

Subject, Classification by


a method of analytic and synthetic processing of printed material according to content. Classification by subject has many aspects and involves the selection of subjects and their designation, generally in standard terminology, as well as their characteristics and relationships. The word “subject” means any object of thought that is of interest to a reader and that is referred to in a text. The object of classification by subject is generally an entire published work—a book, brochure, or journal, or its parts—chapters, sections, pages, or articles.

Material that undergoes classification by subject may also be other sources of information or inquiries for information. In analyzing a text and formulating subject headings, the circumstances under which this classification method is used and the characteristics of the document being classified are taken into account. For example, when a book is classified by subject for a library catalog, consideration is given not only to its content but also to its form and purpose: whether it is meant for the reading public or for some special purpose.

The practical procedures and rules for classification by subject are the content both of the general methodology of this type of classification—used for all types of documents regardless of their subject matter—and of particular methodologies that are determined by the nature of the object being classified and by concrete information retrieval tasks; examples of such tasks are classification by subject of medical literature or of dissertation abstracts.

Classification by subject is used extensively in compiling subject catalogs, auxiliary subject indexes, subject indexes for literature, and other information retrieval systems. The common features of subject-heading languages and descriptory languages that have been established by information science permit classification by subject to be regarded as a form of indexing.


Kruglikova, V. P. Predmetizatsiia proizvedenii pechati. Moscow, 1967.
Mikhailov, A. I., A. I. Chernyi, and R. S. Giliarevskii. Osnovy informatiki, 2nd ed. Moscow, 1968.


References in periodicals archive ?
Arranged by title, the idea is for the books to elude their classification by subject and mingle with books on photography of which the library of the Centre has an extensive collection.
There are further codes of classification by subject, for example CHAR ('Charities'), DF ('Death in the family and among acquaintances'), FGEN ('Family origins and genealogies').
The categorizer can "read" an electronic document, determine classification by subject, and then route it to the appropriate individual via e-mail -- all without human intervention.

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