Dewey Decimal Classification : Brief Information of DDC

History of Dewey Decimal Classification (DDC)

The Dewey Decimal Classification (DDC) system is a general knowledge classification tool used in library classification that is continuously revised to keep pace with current knowledge. This system first published in the United States of America by Melvil Dewey in 1876. Currently DDC is published by OCLC (Online Computer Library Center), and it is the most widely used classification system in the world translated into more than 30 languages. It has been revides and expended through 23 major editions and the latest issued in 2011.

Dewey Decimal Classification (DDC) is the most popular of all the modern library classification schemes. It was devised by Melville Dewey in 1876. It provides a systematic arrangement of all the materials mechanized by notation of great simplicity and apparent flexibility. With the emergence of DDC, the principle of relative location of books on shelf according to the subject became perfectly feasible and it replaced the then existing practice of a fixed location, when a certain number of shelves were allotted to each subject and each book was identified by the shelf number and its position on the shelf. As a matter of fact, all our decimal fraction notation, but for the convenience of remembering the number, the decimal point is inserted after the third digit. Sub-divisions are carried out decimally and all numbers are read as decimals. At each stage, there are nine coordinate divisions whenever there are more than nine divisions of equal status, the eight are named and the remaining are covered in the nine division i.e. ‘others’. The use of simple and pure notation that is Indian numbers, provision of form division andrelative index has made DDC very popular.

Different Editions of DDC:

Features of the Dewey Decimal Classification:

Decimal Classification is an almost enumerative scheme of classification. Since 1876 to 2011(23^rd edition) this scheme did not look back, and its popularity has grown day by day throughout the world. This statement can be justified by the fact that DC has been translated into many languages, such as Chinese, Spanish, Danish, Turkish, Japanese, Hindi, Portuguese, Sinhalese and several other languages across the globe. Dewey introduced the notion of using notation for the subjects in his scheme and applying the notation to the book and not to the shelves. But certain features forming the basis of its present form can be still recognized as follows:

1. Universal Scheme: A distinctive feature of the DDC is that its classes reflect all the areas of specialized knowledge developed in modern society. These specialized areas are loosely put together in the main classes in the scheme, able it in this manner the principle of collation of bringing of related subjects in close proximity is sometimes violated.
2. Relative Location: In his scheme, Melvil Dewey introduced the brainwave of‘relative location’ as opposed to ‘fixed location.’ For this purpose, heutilized the decimal notation consisting of Arabic numerals for the subjects and assigning that notation to the books on the basis of thought content and not on the basis of the shelves. In this method, a new book on a given subject may be put in between the existing sequence at the required position, directed by the notation assigned to that book and there is no necessity to put the book at the end of the sequence as had been the practice in “fixed location.”
3. Decimal Notation: Melvil Dewey used decimal fraction notation for the arrangement of knowledge on the shelves. Indo-Arabic numerals (0 to 9) are used decimally for the sub-divisions of knowledge. In this process, the universe of subjects is divided into ten main classes, each of which is again divided into ten divisions. Again each division is further divided into ten sections. At each stage of division, a given number is sub-divided decimally. All the class numbers in DDC are decimal fractions.
4. Minute Division: The first edition of DDC consisted of only 42 pages and at that time, it was criticized for its being too broad in its sub-division. The number of pages had since been increasing as shown in Table 1. This growth suggests the enormous number of sub-divisions which are possible and useful for minute classification. Dewey emphasized the need of minute division as “the advantage of close classing is unquestioned if the user knows just what it is.”
5. Mnemonics: Another important feature of DDC is mnemonics, which means ‘aid to memory.’ In DDC, mnemonics are available for subject synthesis. The use of consistent order in the subject division of different classes produces mnemonics. There are various tables, such as, Area Table, Language Table, Standard Division Table, etc. which are used to achieve subject synthesis. The user may also find Scheduled Mnemonics, Systematic Mnemonics and Alphabetical Mnemonics at a few places in DDC.
6. Integrity of Numbers: One of the most important features of DDC is the integrity of numbers. To incorporate new developments and to keep pace with the growth of knowledge, a scheme of classification should be revised continually, without changing the basic structure, so that the professionals may accept the revised edition without hesitation.
7. Auxiliary Tables: Auxiliary tables provide an important basis for preparing numbers and lead to uniform meanings of numbers when used in various contexts. A document, which is a source of knowledge, always has some physical form. Melvil Dewey in the second edition of the scheme published in 1885 introduced the concept of “Form Divisions” to be used for the sub-divisions of a subject based on the characteristics of documents, either in accordance with the point of view of the author, i.e. Bibliographical, Philosophical, Theoretical, Historical or in accordance with the form of thought content in documents, i.e. Digest, Manual, Monograph, Dictionary, Periodical or Manual. The “form divisions,” could be attached to any class number according to the instructions provided therein. The system of ‘form divisions’ remained in use up to the 12^th edition. The 13^th edition consisted of 5 “Auxiliary Schedules.” The 14^th edition had 4 tables. In the 15^th edition, the conventional 9 form divisions, i.e. 01-09 were annexed along with the tables,without any detailed sub-divisions. The word ‘Form divisions’ was replaced by“Standard Subdivisions’ in the 17thedition, along with new area table in volume 2(Index). The 18^th, 19^th and 20^th editions consist of 7 auxiliary tables which are detailed under DDC 20.

Structure of Dewey Decimal Classification:

1. Schedule: A basic premise of DDC is that it is arranged by discipline and not by subject. At the broadest level, the DDC is divided into ten main classes, which together cover the entire world of knowledge. Each main class is further divided into ten divisions, and each division into ten sections (not all the numbers for the divisions and sections have been used). The three summaries of the DDC are as given:
2. Summaries: Summaries provide an overview of the intellectual and notational structure of classes. Three types of summaries appear in the schedules and tables of DDC. The summaries of the schedules as a whole are found at the front of the schedules (Volume 2-3). Single level summaries in the schedules and tables provide an overview of classes that have sub-divisions extending over more than two pages. Multi-level summaries are provided for eight major divisions and the Area Tables for Europe and North America.

The First Summary: Contains the ten main classes. The first digit in each three-digit number represents the main class.

The Second Summary: Contains the hundred divisions. The second digit in each three-digit number indicates the division.

The Third Summary: contains thousand sections. The third digit in each three-digit number indicates the section. Thus 530 is used for general works on physics, 531 for classical mechanics, 532 for fluid mechanics, 533 for gas mechanics. Arabic numerals are used to represent each class in the DDC. A decimal point follows the third digit in a class number, after which division by ten continues to the specific degree of classification needed.

DDC Relative Index:

Relative index is appended to the schedules of book classification. It is the most important feature of this scheme; arranged in an alphabetical order and aims to include all topics expressed or implied in the main tables together with every likely synonym. Theindex is comprehensive one but exhaustive. The topics whichare further sub-divided inthe table are entered in the bold face type. The specific items in the sub-divisions areentered directly under their own name. The index is relative in the sense that each phaseof the subject is noted. If a topic is treated intwo or more classes, the number it takes ineach group is taken. The use of the index is not limited to locating topic in the tables, ithas equal value in locating topic on the shelves and in fact the reader’s key to the shelfarrangement in every library in which the DDC is being used.

Revision of the Scheme:

The main method of revision has been the result of publication of new editions. Revisions usually take the following forms: Expansion, Relocation, and Reduction and Phoenix schedules. The last form is the most far-reaching form of revision. However, “DDC & Decimal Classification: additions, notes and decision’ is a beneficial means by which modifications can be announced in advance of a forthcoming latest edition.

References: (This document is collected from materials available from online/web and organize here for LIS students)

1. KRISHAN KUMAR. Theory of classification. 1993. Vikas Publishing; New Delhi. p1.
2. SHARMA (C D). Use of libraries: A guide to better use of libraries and their resources. 1978. Metropolitan Book; New Delhi. p-120.
3. SHARMA (C D). Op. cit., p 121.
4. KRISHAN KUMAR. Op. cit., p 4.
5. INDIRA GANDHI NATIONAL OPEN UNIVERSITY (IGNOU). Unit 2: Needand purpose of library classification. IGNOU; New Delhi. p 26.
6. DUTTA (Dwijendranath). Library classification: Theory and practice. 1962. The Western Book Depot; Nagpur. p 48.
7. RAJU (Addepali Appala Narasimha). Dewey decimal classification (DDC 20): Theory and practice: A practical and self instructional manual. 1995. T.R. Publications; Madras. p 4.
8. CHOWDHURY (G G). Introduction to modern information retrieval. Ed. 3. 2004. Facet Publishing; London. p 89.

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