Can you describe what you mean by close and broad classification?

The Dewey Decimal Classification provides the basic option of close versus broad classification. Close classification means that the content of a work is specified by notation to the fullest extent possible. Broad classification means that the work is placed in a broad class by use of notation that has been logically abridged. For example, a work on French cooking is classed closely at 641.5944 (641.59 Cooking by place + 44 France from Table 2), or broadly at 641.5 (Cooking). A library should base its decision on close versus broad classification on the size of its collection and the needs of its users. For example, a work on the sociology of sibling relationships in Canadian society would be most usefully classed in 306.8750971 (306.875 Sibling relationships + 09 Geographic treatment from Table 1 + 71 Canada from Table 2) in a research library or large public library. A small school library might prefer to class the same work in the broader number (306.875) without including the geographic facet in the notation. An engineering library might prefer close classification for works in engineering, but broad classification for disciplines outside science and technology.

One can use the segmentation marks provided by the Decimal Classification Division of the Library of Congress and some other centralized cataloging services as a guide to abridging numbers for broad classification purposes. Segmentation marks are also available in WorldCat. The abridged edition of the Dewey Decimal Classification is another source for broad classification.

Last revised: 08 April 2005