Today's topic is Universal Decimal Classification (UDC), written specially for LIS students preparing for NET/SET, KVS, DSSSB, and other librarian examinations.
Topic: UNIVERSAL DECIMAL CLASSIFICATION (UDC) (Library Science)
1. Introduction
Universal Decimal Classification (UDC) is a general, analytico-synthetic, faceted classification system used for organizing knowledge in libraries and documentation centres. It allows detailed subject representation through the combination of numbers, symbols, and auxiliaries.
UDC is particularly suitable for large, multilingual, and specialized collections, and is widely used in Europe, Asia, and international documentation systems.
2. Origin and Historical Development
UDC was developed in 1895
Founders:
Paul Otlet (1868–1944)
Henri La Fontaine (1854–1943)
Based on the 5th edition of Dewey Decimal Classification (DDC)
Purpose of Development
- UDC was created for:
- The International Bibliographic Repertory (RBU) in Brussels
- Managing international bibliographic records
- Overcoming limitations of DDC in subject synthesis and expansion
Major Milestones
1895: First outline published
1905–1907: First complete schedules issued
1933–1951: Large-scale revisions
1992: Introduction of Master Reference File (MRF)
2009 onwards: Web-based UDC services expanded
2.1 First Outline Edition (1895)
Title: Manuel du Répertoire Bibliographique Universel
Language: French
Year: 1895
Editors:
Paul Otlet
Henri La Fontaine
Publisher: Institut International de Bibliographie (IIB), Brussels
Significance:
- First conceptual outline
- Introduced decimal expansion beyond DDC
- Basis for international bibliographic control
2.2 First Complete Edition (1905–1907)
Title: Classification Décimale Universelle (CDU)
Years of publication: 1905–1907
Language: French
Publisher: IIB, Brussels
Nature:
- First full-scale schedules
- Introduced auxiliary tables and symbols
Importance:
Established UDC as an independent classification system
2.3 German Edition (1934–1953)
Title: Dezimalklassifikation
Language: German
Years: 1934–1953
Publisher: Beuth Verlag, Berlin
Importance:
- Most systematic and scholarly edition
- Widely used in Europe
- Basis for later editorial refinements
2.4 English Edition (1936 onwards)
Title: Universal Decimal Classification
Language: English
Publisher:
British Standards Institution (BSI)
Later: UDC Consortium
Significance:
- Popularized UDC in English-speaking countries
- Used in Commonwealth nations and Asia
2.5 Abridged English Edition (1961)
Title: Abridged Universal Decimal Classification
Year: 1961
Publisher: British Standards Institution
Nature:
- Condensed version
- Suitable for small libraries
2.6 Complete English Edition (1960s–1980s)
Title: Universal Decimal Classification: Complete English Edition
Publisher: BSI
Format: Multi-volume print schedules
Features:
Detailed auxiliary tables
Used in academic and research libraries
3. Nature and Characteristics of UDC
UDC is:
Universal: Covers all fields of knowledge
Decimal: Uses base-10 notation
Analytico-synthetic: Subjects are analyzed and synthesized
Faceted: Allows combination of concepts
Hospitality-rich: Infinite extension possible
Language-independent: Numerical notation usable worldwide
4. Main Classes of UDC
- 0 – Generalities, Science and Knowledge, Information, Documentation
- 1 – Philosophy. Psychology
- 2 – Religion. Theology
- 3 – Social Sciences
- 4 – Vacant (earlier Philology; now unused)
- 5 – Mathematics and Natural Sciences
- 6 – Applied Sciences, Medicine, Technology
- 7 – Arts, Entertainment, Sports
- 8 – Language, Linguistics, Literature
- 9 – Geography, Biography, History
5. Notation in UDC
- UDC uses mixed notation, including:
- Arabic numerals (main notation)
- Auxiliary signs and symbols
Important Symbols and Their Meaning
+ (Addition): Related subjects
Example: 94+82 (History + Literature)
: (Relation): Interrelated subjects
Example: 316:004 (Society and computers)
/ (Range): Consecutive numbers
Example: 621.3/621.5
[ ] (Subgrouping): Grouping of numbers
= (Language auxiliary):
Example: =111 (English)
" " (Time auxiliary):
Example: "19" (20th century)
( ) (Common auxiliaries): Place, form, etc.
6. Auxiliaries in UDC
Auxiliaries are a distinctive feature of UDC.
6.1 Common Auxiliaries
Applicable to all subjects.
Major types include:
Place – (44) France, (540) India
Time – "1947"
Language – =133.1 French
Form – (0...) dictionaries, handbooks
Ethnic grouping
Materials
Properties
6.2 Special Auxiliaries
- Applicable only to specific classes
- Provide detailed subdivision within subjects
- Enclosed in hyphen (-) or dot (.0...)
7. Tables in UDC
UDC consists of:
- Main Tables
- Auxiliary Tables
Unlike DDC, UDC does not restrict the number of tables strictly; auxiliaries are integrated throughout schedules.
The Master Reference File (MRF) contains:
Approximately 70,000+ classes
Maintained digitally
8. Facet Analysis and Synthesis
UDC supports:
Subject analysis into components
Synthesis using symbols
Example:
> “Economic development in India after 1991”
UDC number may combine:
Economics
Development
Place (India)
Time (post-1991)
This makes UDC more flexible than enumerative systems.
9. UDC Editions and Formats
9.1 Full (Unabridged) Edition
- Contains complete schedules and auxiliaries
- Used by large and research libraries
9.2 Abridged Edition
- Simplified version
- Suitable for small libraries
9.3 Electronic and Web Editions
- UDC Online
- UDC Master Reference File (MRF)
- Maintained by UDC Consortium
10. UDC Consortium
Established in 1992
Headquarters: The Hague, Netherlands
Responsible for:
- Revisions and updates
- Licensing
- Editorial control
- Multilingual translations
11. Revision Policy
- UDC follows continuous revision
- Changes published annually
Ensures:
- Inclusion of new disciplines
- Terminology updates
- Structural consistency
12. Comparison with DDC (Brief Points)
UDC is more synthetic than DDC
UDC allows complex subject combinations
DDC is more enumerative
UDC uses symbols extensively
UDC better suits documentation and research libraries
13. Merits of UDC
- High degree of specificity
- Suitable for multidisciplinary subjects
- International acceptance
- Excellent for indexing and retrieval
- Supports machine-readable formats
14. Limitations of UDC
Complex notation
Requires trained classifiers
Frequent revisions demand updating
Not ideal for very small libraries
15. Present Status and Use
- UDC is widely used in:
- National libraries
- Documentation centres
- Special libraries
- Digital repositories
- European and Asian library systems
16. Examination Importance (NET/SET)
Frequently asked areas:
- Founder and year
- Symbols and auxiliaries
- Differences between DDC and UDC
- UDC Consortium
- Analytico-synthetic nature
- MRF and web editions