Dewey decimal classification (DDC.)
The Dewey decimal classification (DDC, also called the Dewey Decimal System) is a proprietary system of library classification developed by Melvil Dewey in 1876.
It has been greatly modified and expanded through 23 major revisions, the most recent in 2011.[2] This system organizes books on library shelves in a specific and repeatable order that makes it easy to find any book and return it to its proper place. The system is used in 200,000 libraries in at least 135 countries.
A designation such as Dewey 16 refers to the 16th edition of the DDC.
Design
The DDC attempts to organize all knowledge into ten main classes. The ten main classes are each further subdivided into ten divisions, and each division into ten sections, giving ten main classes, 100 divisions and 1000 sections. DDC's advantage in using decimals for its categories allows it to be purely numerical; while the drawback is that the codes are much longer and more difficult to remember as compared to an alphanumeric system. Just as an alphanumeric system, it is infinitely hierarchical. It also uses some aspects of a faceted classification scheme, combining elements from different parts of the structure to construct a number representing the subject content (often combining two subject elements with linking numbers and geographical and temporal elements) and form of an item rather than drawing upon a list containing each class and its meaning.
Except for general works and fiction, works are classified principally by subject, with extensions for subject relationships, place, time or type of material, producing classification numbers of at least three digits but otherwise of indeterminate length with a decimal point before the fourth digit, where present (for example, 330 for economics + .9 for geographic treatment + .04 for Europe = 330.94 European economy; 973 for United States + .05 form division for periodicals = 973.05 periodicals concerning the United States generally).
Books are placed on the shelf in increasing numerical order of the decimal number, for example, 050, 220, 330, 330.973, 331. When two books have the same classification number the second line of the call number (usually the first letter or letters of the author's last name, the title if there is no identifiable author) is placed in alphabetical order.
The DDC has a number for all books, including fiction: American fiction is classified in 813. Most libraries create a separate fiction section to allow shelving in a more generalized fashion than Dewey provides for, or to avoid the space that would be taken up in the 800s, or simply to allow readers to find preferred authors by alphabetical order of surname.
Some parts of the classification offer options to accommodate different kinds of libraries. An important feature of the scheme is the ability to assign multiple class numbers to a bibliographical item and only use one of them for shelving. The added numbers appear in the classified subject catalog (though this is not the usual practice in
North America). For the full benefit of the scheme the relative index and the tables that form part of every edition must be understood and consulted when required. The structure of the schedules is such that subjects close to each other in a dictionary catalog are dispersed in the Dewey schedules (for example, architecture of
Chicago quite separate from geography of
Chicago).
Classes listed
The system is made up of seven tables and ten main classes, each of which are divided into ten secondary classes or subcategories, each of which contain ten subdivisions.
The tables are:
Standard subdivision
Areas
Subdivision of individual literatures
Subdivisions of individual languages
Racial, ethnic, national groups
Languages
Persons
The classes are:
000 – Computer science, information and general works
100 – Philosophy and psychology
200 – Religion
300 – Social sciences
400 – Language
500 – Science (including mathematics)
600 – Technology and applied Science
700 – Arts and recreation
800 – Literature
900 – History, geography, and biography
Administration and publication
While he lived, Melvil Dewey edited each edition himself: he was followed by other editors who had been very much influenced by him. The earlier editions were printed in the peculiar spelling that Dewey had devised: the number of volumes in each edition increased to two, then three and now four.
The Online Computer Library Center of Dublin, Ohio, United States, acquired the trademark and copyrights associated with the DDC when it bought Forest Press in 1988. OCLC maintains the classification system and publishes new editions of the system. The editorial staff responsible for updates is based partly at the Library of Congress and partly at OCLC. Their work is reviewed by the Decimal Classification Editorial Policy Committee (EPC), which is a ten-member international board that meets twice each year. The four-volume unabridged edition is published approximately every six years, the most recent edition (DDC 23) in mid 2011.[5] The web edition is updated on an ongoing basis, with changes announced each month.[6]
The work of assigning a DDC number to each newly published book is performed by a division of the Library of Congress, whose recommended assignments are either accepted or rejected by the OCLC after review by an advisory board; to date all have been accepted.[citation needed]
In September 2003, the OCLC sued the Library Hotel for trademark infringement. The settlement was that the OCLC would allow the Library Hotel to use the system in its hotel and marketing. In exchange, the Hotel would acknowledge the Center's ownership of the trademark and make a donation to a nonprofit organization promoting reading and literacy among children.
DDC's numbers formed the basis of the more expressive but complex Universal Decimal Classification (UDC), which combines the basic Dewey, numbers with selected punctuation marks (comma, colon, parentheses, etc.). Adaptations of DDC for specific regions outside the English-speaking world include the Korean Decimal Classification, the New Classification Scheme for Chinese Libraries and the Nippon Decimal Classification (Japanese).
Comparison with Library of Congress Classification
For more details on this topic, see Comparison of Dewey and Library of Congress subject classification.
This section may contain original research. Please improve it by verifying the claims made and adding references. Statements consisting only of original research may be removed. More details may be available on the talk page. (November 2008)
Besides its frequent revision, DDC's main advantage over its chief American rival, the Library of Congress Classification system developed shortly afterward, is its simplicity. Thanks to the use of pure notation, a mnemonics system and a hierarchical decimal place system, it is generally easier to use.[citation needed]
DDC and UDC are more flexible than Library of Congress Classification because of greater use of facets (via auxiliary tables) while Library of Congress Classification is almost totally enumerative.
DDC's decimal system means that it is less hospitable to the addition of new subjects, as opposed to Library of Congress Classification, which has 21 classes at the top level. DDC notations can be much longer compared to other classification systems.
Another disadvantage of DDC is that it was developed in the 19th century essentially by one man and was built on a top-down approach to classify all human knowledge, which makes it difficult to adapt to changing fields of knowledge. The Library of Congress Classification system was developed based mainly on the idea of literary warrant; classes were added (by individual experts in each area) only when needed for works owned by the Library of Congress. As a result, while the Library of Congress Classification system was able to incorporate changes and additions of new branches of knowledge, particularly in the fields of engineering and computer science (the greater hospitability of the Library of Congress Classification was also a factor), DDC has been criticized for being inadequate in covering those areas. It is asserted that, as a result, most major academic libraries in the US do not use the DDC because the classification of works in those areas is not specific enough, although there are other reasons that may truly be more weighty, such as the much lower expense of using a unique "pre-packaged" catalog number instead of having highly skilled staff members engaging in the time-consuming development of catalog numbers.
The Library of Congress Classification system is not without problems. For example, it is highly US-centric because of the nature of the system, and it has been translated into far fewer languages than DDC and UDC.
Understanding Call Numbers
What are call numbers for?
Each book in the library has a unique call number. A call number is like an address: it tells us where the book is located in the library. Call numbers appear
Note that the same call number can be written from
top-to-bottom, or left-to-right.
Sierra College, like many libraries in the U.S., usesDewey Decimal Classification for call numbers. This system uses a combination of numbers and some letters to arrange materials by subjects.
Reading Call Numbers
Putting Call Numbers in Shelf Order
To understand how call numbers are put in order in Dewey Decimal Classification, again look at each section of the call number.
What does the call number mean?
Remember that Dewey decimal classification arranges materials by subjects. The first section of the call number represents the subject of the book. The alphanumeric section of the call number often represents the author's last name.
Why is this important to know?
Because books are classified by subject, you can often find several helpful books on the same shelf, or nearby. For example, within the same call number 333.79, there are other books about energy.
333.79 P966 - Prospects for Energy in America
333.79 R411 - Renewable Energy
333.79 S641 - Energy at the Crossroads
333.79 V132 - Power to the People
Since Dewey decimal classification arranges materials by subjects, knowing the number for your subject area gives you a place to start browsing the shelves.
