Library Classification - Types

Types

There are many standard systems of library classification in use, and many more have been proposed over the years. However in general, classification systems can be divided into three types depending on how they are used:

• Universal schemes covering all subjects. Examples include Dewey Decimal Classification, Universal Decimal Classification and Library of Congress Classification

• Specific classification schemes for particular subjects or types of materials. Examples include Iconclass, British Catalogue of Music Classification, and Dickinson classification, or the NLM Classification for medicine.

• National schemes specially created for certain countries. An example is the Swedish library classification system, SAB (Sveriges Allmänna Biblioteksförening).

In terms of functionality, classification systems are often described as:

• enumerative: subject headings are listed alphabetically, with numbers assigned to each heading in alphabetical order.
• hierarchical: subjects are divided hierarchically, from most general to most specific.
• faceted or analytico-synthetic: subjects are divided into mutually exclusive orthogonal facets.

There are few completely enumerative systems or faceted systems; most systems are a blend but favouring one type or the other. The most common classification systems, LCC and DDC, are essentially enumerative, though with some hierarchical and faceted elements (more so for DDC), especially at the broadest and most general level. The first true faceted system was the Colon classification of S. R. Ranganathan.