THE DEWEY DECIMAL CLASSIFICATION - OCLC

Mitchell and Vizine-Goetz: The Dewey Decimal ClassificationHierarchy in the DDC is expressed through structure and notation. The DDC organizesknowledge first by discipline and then by subject in a hierarchical structure in whichtopics progress from the general to the specific. Each of the classes subordinate to the tenmain classes needs to be considered in terms of the hierarchy. Notes with “hierarchicalforce” regarding the nature of a class at any point in the hierarchy also apply tosubordinate classes and to referenced classes.The hierarchy is largely expressed through the notation. For a class within a givenhierarchy, the next broader topic will generally be represented by a number one digitshorter, and subordinate topics will generally be one digit longer. Coordinate topics areusually represented by the same number of digits. For example, here are several specificice and snow sports shown in the context of their complete hierarchy.700 Arts & recreation790 Recreational and performing arts796 Athletic and outdoor sports and games796.9 Ice and snow sports796.91 Ice skating796.92 Snowshoeing796.93 Skiing and snowboardingThe classes 796.91, 796.92, and 796.93 are coordinate classes—they are directlysubordinate to class 796.9 Ice and snow sports, which in turn is subordinate to section796 Athletic and outdoor sports and games. Section 796 is part of division 790Recreational and performing arts, which is part of main class 700 Arts & recreation.http://www.oclc.org/research/publications/library/2009/mitchell-dvg-elis.pdf Page 8 of 36.