Colon classification

Colon classification
Name	Colon classification
Creator	S. R. Ranganathan
Classification	Faceted classification
Released	1933
Latest version	7th edition (1987)
Related	Universal Decimal Classification, Bliss bibliographic classification
Used in	Specialized libraries, documentation centers

Colon classification. It is a system of library classification developed by the Indian mathematician and librarian S. R. Ranganathan. First published in 1933, it introduced the revolutionary concept of faceted classification, which organizes knowledge by combining distinct conceptual categories. This system was designed to provide a more flexible and hospitable structure for organizing documents than the prevalent enumerative systems like the Dewey Decimal Classification.

Overview

The system was conceived by S. R. Ranganathan at the University of Madras as a solution to the rigidity he observed in existing schemes. Its core philosophy is articulated in his famous Five Laws of Library Science, which emphasize the dynamic nature of knowledge. Unlike static systems, it allows for the synthesis of class numbers through the combination of discrete elements, making it particularly suited for complex and emerging subjects in fields like nuclear physics and molecular biology. The name derives from the use of the colon punctuation mark to separate these combined facets.

Notation and structure

The notation employs a mixed system, using letters from the Roman alphabet, Indic numerals, and various punctuation marks as facet indicators. The colon is the primary facet separator, but other marks like the semicolon, comma, and parentheses denote different types of relationships between concepts. This syntax creates a mnemonic and expressive class number that reflects the subject's analytical structure. The structure is fundamentally post-coordinate, meaning the final class number is assembled from its constituent parts rather than chosen from a pre-made list.

Fundamental categories

Ranganathan postulated a set of five fundamental categories that form the basis for analyzing any subject: Personality, Matter, Energy, Space, and Time, often remembered by the acronym PMEST. These categories provide a consistent framework for facet analysis. For example, in the subject "treatment of lung cancer in Japan during the 1990s," Personality might be medicine, Matter the lung tissue, Energy the therapeutic action, Space Japan, and Time the 1990s. This analytical method ensures a predictable and logical order for combining facets.

Principles of facet analysis

Facet analysis involves dissecting a complex subject into its core conceptual components based on the fundamental categories. The process follows specific rules for citation order, typically the PMEST sequence, which dictates the arrangement of facets within the class number. This principle of facet sequence ensures consistency across the entire classification. The system's hospitality, or ability to accommodate new subjects, is achieved by interpolating new isolates within a facet or adding new facets entirely, a process more organic than the revision required by the Library of Congress Classification.

Comparison with other classification systems

In contrast to enumerative systems like the Dewey Decimal Classification and the Library of Congress Classification, which list pre-combined subjects, this system is synthetic and faceted. It shares philosophical ground with the Bliss bibliographic classification in its analytical approach but is more explicitly structured around the PMEST formula. While the Universal Decimal Classification also uses facet-like auxiliaries, its primary structure remains enumerative. The system's deep structural logic made it a foundational model for modern information retrieval systems and ontologies, influencing later developments like the British Catalogue of Music Classification.

Applications and influence

Although not widely adopted for general library shelving due to its complexity, it has been profoundly influential in the theory of knowledge organization. It is used in specialized documentation centers, particularly in South Asia, and its principles underpin many modern thesauri and information architecture designs. The system directly inspired the development of the Broad System of Ordering and informed the design of early computerized cataloging systems. Ranganathan's work, centered at the Documentation Research and Training Centre in Bangalore, established a lasting school of thought in library and information science, impacting international standards and the development of the Semantic Web.

Category:Library classification systems Category:Information science Category:Works by S. R. Ranganathan