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How does the Library of Congress Classification differ from the Dewey Decimal Classification?
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Reading Room of the British Museum, designed by Sidney Smirke in collaboration with Anthony Panizzi and built in the 1850s. Illustration by Smirke, from the Illustrated London News, 1857.
The Library of Congress Classification (LCC) and the Dewey Decimal Classification (DDC) differ significantly in their structure, notation, and application:
- Structure: DDC divides all knowledge into 10 main numerical groups, which are further subdivided hierarchically using decimals. In contrast, LCC divides knowledge into 20 large classes plus a class for general works, utilizing a system based on an actual collection of books rather than a purely theoretical division.123
- Notation: DDC uses a purely numerical system, which provides mnemonic aids through constant repetition of patterns. LCC uses a mixed notation of capital letters and Arabic numerals, allowing for greater specificity without excessively long codes.123
- Design Philosophy: DDC is designed to be adaptable to libraries of various sizes and emphasizes ease of use through its relative index and mnemonic features. LCC was developed for a large research collection and is favored by university, special, and government libraries due to its ability to handle minute subject groupings and complex geographic or historical subdivisions.13
While both are widely used in North American libraries, they reflect different approaches to organizing information.2