Dewey Decimal Classification

Dewey Decimal Classification. The Dewey Decimal Classification (DDC) is a proprietary library classification system first published in the United States by Melvil Dewey in 1876. It organizes knowledge into ten main classes, each further divided decimally, providing a notation system for arranging library materials by subject. It is the world's most widely used library classification system, maintained by the OCLC through its editorial office at the Library of Congress.

History and development

The system was conceived by Melvil Dewey while working at the Amherst College library, with the first edition published anonymously in 1876. Dewey was influenced by earlier systems like the Baconian method and the work of William Torrey Harris. The Lake Placid Club Education Foundation later held the copyright, with stewardship eventually transferring to the OCLC in 1988. Key developments include the introduction of the "Relative Index" and the establishment of the Decimal Classification Editorial Policy Committee to guide updates. The system's expansion mirrored the growth of academic publishing and the professionalization of librarianship in the 20th century.

Structure and notation

The structure is built on ten main classes covering broad fields like Philosophy (100s), Social sciences (300s), and Literature (800s). Each class is subdivided decimally into ten divisions, and further into ten sections, creating a hierarchical notation of at least three digits. The notation uses Arabic numerals and a decimal point, allowing for infinite expansion. Auxiliary tables provide standard subdivisions for concepts like form, geography, and language, applied through add instructions. Cutter numbers, often derived from the Cutter Expansive Classification, are frequently appended to create unique call numbers.

Use in libraries

It is employed by over 135 countries, most notably in public and school libraries across the United States, the United Kingdom, and Australia. The system facilitates shelf arrangement in browse order, enabling patrons to find materials on related subjects physically adjacent. OCLC provides the classification data via WebDewey, integrated into many integrated library system platforms. National libraries like the British Library have historically used it for certain collections, though many large academic institutions prefer the Library of Congress Classification.

Editions and updates

The first abridged edition was published in 1894, with the first full edition in 1885. Major revisions occurred in the 14th edition (1942) and the 15th edition (1951), which introduced the concept of "Phoenix schedules" for complete restructuring of certain classes. Current updates are managed by the OCLC's editorial team, with a new full edition published approximately every seven to ten years; the 23rd edition was released in 2011. Continuous revision is published in the *DC&* newsletters and incorporated electronically.

Comparison with other classification systems

Unlike the enumerative Library of Congress Classification, it is fundamentally hierarchical and uses a pure notation of Arabic numerals. It contrasts with faceted systems like the Colon classification developed by S. R. Ranganathan, which synthesizes notation from multiple elements. While the Universal Decimal Classification (UDC) derives from it, the UDC incorporates auxiliary signs like brackets and colons to denote relationships. The Bliss bibliographic classification offers an alternative philosophical structure based on scientific consensus, but sees limited adoption.

Criticism and limitations

Critics, including the American Library Association, have noted inherent biases reflecting its late-19th century Western world origins, particularly in the treatment of non-Western religions and cultures. The notation can become lengthy for complex subjects, and the decimal structure can impose artificial constraints on emerging interdisciplinary fields like nanotechnology. The proprietary nature controlled by OCLC has sparked debate about access and cost, especially for libraries in the Global South. Some argue its structure reinforces outdated epistemological divisions from the Victorian era.