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FAQs on DDC in general and on using DDC Deutsch

DDC - general

1. Why has a classification system – the DDC – been chosen which was primarily developed from an American perspective?

The desire to use the DDC in Germany came from libraries which wanted to offer their foreign Anglo-American data (which is already enriched with DDC numbers) in their online catalogues and German to access it, and from institutions which required an internationally widespread non-language-based subject cataloguing tool for their cataloguing (especially for web documents). For the Deutsche Nationalbibliografie, using the DDC as a structuring tool involved adapting the Nationalbibliografie to the most widely deployed universal classification system in the world which is used by the national bibliographies of more than sixty countries for subject cataloguing.

2. Can a classification system, the origins of which are rooted in the scientific understanding of the 19th century, adequately reflect the modern world?

The upper levels of the hierarchy (cf. the overviews) do indeed reflect an outdated classification of the sciences; modern aspects are often embedded at lower levels in the hierarchy and can then be further differentiated. Through a process of continuous revision the DDC attempts to reflect the terminology of modern topics and disciplines by including them at a suitable point within the structure, although one which does not always match their present-day significance. In contrast to use of the DDC as a shelving system, the occasionally implausible hierarchical level of a topic or subdiscipline does not, however, represent a disadvantage for catalogue or web searches.

3. Why, despite its claim to represent a universal classification system, does the DDC structure different subjects to different depths?

The basic structure of the DDC has not been changed since its creation at the end of the 19th century. Accordingly, innovatory subjects with new subdisciplines and extensive literature are more finely structured than others. Furthermore, the DDC's ability to allow further differentiation (e.g. by time, place, language, form of presentation and designated community) through the use of auxiliary tables does not function the same way in all subjects. For instance, the main classes 400 (Language) and 800 (Literature) have relatively few subdivisions, yet are differentiated by code, whereas the opposite is the case for technology and the natural sciences.

4. How it is ensured that German and Central European aspects are adequately reflected in DDC?

The DDC Deutsch project had a positive effect on the 22nd Edition of the DDC Standard Edition published in July 2003 (DDC 22 English): the history of Germany and Austria was revised in the DDC schedules, Germany's party system was included and the proposals which had been submitted along with those other European countries for revisions of the legal section were incorporated. In auxiliary table 2, the geographical add numbers for Germany, Austria and Switzerland were revised and partially updated in cooperation with these three countries. The expansion and revision proposals for the print version of the German DDC 22 and for WebDewey Deutsch aimed at representing German and European issues more effectively are being reviewed by the Online Computer Library Center (OCLC) and the Library of Congress (LoC) and, accordingly, may also be included in the Standard Edition of the DDC and WebDewey

(Further information)

5. How fast and in what ways can modern scientific developments be included in the DDC?

The DDC Editorial Policy Committee (EPC) , in which major DDC user groups in the United States and other Anglo-Saxon countries are represented alongside the Library of Congress (LoC), observes developments in the different disciplines, responds to requests from libraries and decides on smaller or even fundamental revisions in individual fields.Adaptations are made in almost every new edition in certain innovative sectors such as information technology; the intervals are longer in other subjects.The ongoing DDC cataloguing of titles submitted to the LoC ensures that new topics are given their own DDC number via the Library of Congress Subject Headings (LCSH) once a minimum number of titles has been published on the topic in question.

6. Why is the use of DDC recommended in German scientific libraries whereas in the United States the university libraries primarily use LCC?

The Library of Congress Classification (LCC) system is used as a shelving system for works in American university libraries and thus performs the tasks that are carried out in Germany by the Regensburger Verbundklassifikation (RVK) and others, above all with regard to the classifications developed for ordering the reference collection. Adopting LCC would make little sense in particular for national bibliographic cataloguing purposes and for Internet use because DDC is the world's most widely used universal classification system. LCC normally now coordinates its revisions and updates with the DDC. The same applies, increasingly, for Universal Decimal Classification (UDC).

7. Should DDC be introduced also for the ordering of reference collections in German libraries?

Support for the shelving of reference collections came both from the classification report for scientific libraries of 1998 as well as from many members of the DDC expert group and its predecessor, the classification working group, and from those involved in the Regensburg Verbundklassifikation (RVK) or in the classification systems used in the regions or in the public library system such as the GHB shelving system, Allgemeine Systematik für Öffentliche Bibliotheken (ASB), Klassifikation für Allgemeinbibliotheken (KAB), etc. From the outset DDC was intended to be used in the Deutschen Nationalbibliografie and in the Internet in German-speaking countries, with access opportunities to follow via online catalogues for Anglo-American foreign data. However, there are also individual libraries with special requirements and a large proportion of English-language literature (such as the John-F.-Kennedy-Instituts at FU Berlin, or the European Central Bank library) which also shelve their collections based on DDC. This is also planned worldwide for the libraries of the Goethe-Institut.
The introduction of the DDC in the Deutschen Nationalbibliografie increased the interest in using it for collection shelving purposes. So far only limited experience has been gathered here: use of the Cutter system for more accurate classification of titles found under the same DDC number plays an important role.

8. Should the university libraries now also assign DDC numbers?

This is not envisaged by the Projekts DDC Deutsch; the DDC numbers used by the university libraries should come from the Library of Congress (LoC), the British Library, the German National Library and from other sources. It is conceivable, however, that the university libraries could serve an intermediary function for institutions within the universities which want to issue DDC numbers to their own publications, or for virtual libraries and similar services which become active DDC users as part of special subject collection projects.

9. Will the introduction of DDC lead to the reduction of verbal subject cataloguing services offered by the German National Library?

The German National Library continues to provide its full range of services for Series A titles of the Deutschen Nationalbibliografie catalogued using RSWK/SWD, and for maintaining the Subject Headings Authority File. For the Series B publications, of which so far only a small portion has been catalogued using RSWK/SWD (humanities, excluding theology), this service was replaced as of the 2006 bibliographical year by DDC cataloguing for all disciplines. From 2006, university publications only listed in Series H have also been catalogued using DDC instead of RSWK/SWD; in addition, the medical dissertations which have not yet been subject catalogued have also been processed using DDC. University publications which also appear in Series A (book trade publications) continue to receive RSWK subject headings. Since the 2007 bibliographical year Series A has also been catalogued using DDC numbers alongside indexing.
See also: Heiner-Freiling, Magda: RSWK und DDC – Sacherschließung auf zwei Beinen. In: Dialog mit Bibliotheken 17, 2005/3, S. 4–13

To print edition and translation

1. When and where was the German DDC edition published?

The print edition of the German version of DDC 22 was published by K. G. Saur Verlag (today De Gruyter Saur) in 2005.
WebDewey Deutsch,, the web application for classification using DDC Deutsch, has been offered by the German National Library since the end of November 2012.
A German edition of the DDC-textbook DDC "Dewey-Dezimalklassifikation: Theorie und Praxis. Lehrbuch zur DDC 22" was published by K. G. Saur (today De Gruyter Saur) in March 2006.

2. When will the next edition of the DDC be published?

The last full English DDC edition, the 23rd edition of the DDC Standard Edition, was issued in mid-2011. Whether or not the German translation of this is released as a print version depends on the amount of interest shown by users and the publishers themselves.

3. What is the difference between the abridged and the full edition of the DDC?

The abridged edition of the DDC is a concise edition of the full version; it contains a logically structured truncation of the number and structural hierarchy of the corresponding full edition. The current English edition of the abridged version is the 15th Edition which was released in 2012. [DDC Abridged Edition 15]

4. Will there be an abridged German edition of the DDC?

There are currently no plans to translate the abridged version of the DDC into German.

5. Does the print edition contain all DDC numbers?

The print editions of the German and English versions of the DDC do not contain all built numbers listed in WebDewey and WebDewey Deutsch. However, these can, of course, be formulated in the same form using the synthesis instructions given in the print edition. In addition, within the seven-year lifespan of an edition, further built numbers are included for more specific topics alongside new numbers for topical developments which are then incorporated in the next print edition.

6. Why are geographical names and other proper names sometimes given in the English and sometimes the German or foreign language spelling?

The spelling of geographical and other proper names in auxiliary table 2 is based - where possible - on the Subject Headings Authority File (SWD and the reference works it uses (e.g. Brockhaus, Knaurs Weltatlas). This means that, in many cases, the German form is preferred for known foreign geographic names, as well as for the names of former German settlement areas. The English spelling is generally preferred for names in English-speaking regions and many parts of the world which use English as a second language (India, Pakistan, and parts of Africa). Also in cases where most references to more remote regions and smaller locations are found in the English spelling, this form receives preference over the lesser known original-language spelling. In these cases, Relative Index terms are also given in the original language spelling, where this is verifiable.

7. Why have DDC class names, instructions and notes not been translated more accurately into German?

Translation of the DDC into foreign languages is carried out based on precise instructions issued by the editors of the English DDC and is subject to their final approval. They attach particular importance to achieving consistently identical foreign-language versions of the instructions, notes and references, as well as of frequently-used class names to the original. Therefore, the same class names, such as "Philosophy and theory", "Auxiliary techniques and procedures; apparatus, equipment, materials" or "Organisations and management" must be used throughout the DDC even if they seem inappropriate in the context of the respective subject or topic. Standard phrases are used both in English and German for instructions, notes and references, as well as instructions for number building. These should provide clear instructions in the most concise form - for which English is doubtless more suitable. Translators and expert consultants have sought to reconcile the required consistency as far as possible with the desired adaptation to the German language. With increasing practical experience of using DDC and possibly growing room for discretion on the part of publishers, there will hopefully be room for improvements in upcoming issues. The German DDC terminology can be found in the glossary to the German edition of the DDC (PDF, 497KB, Not barrier-free file.).


1. How and where is it possible to learn about DDC classification?

The German National Library regularly provides training on DDC classification. Further information and the current schedules can be found in the DDC-Further Training section.
The introduction to the print edition of DDC 22 (PDF, 926KB, Not barrier-free file.) contains an outline of the basic principles and structures of DDC.

The textbook "Dewey-Dezimalklassifikation: Theorie und Praxis. Lehrbuch zur DDC 22" provides an extensive introduction to the structures and rules of DDC and practical exercises in various disciplines.

2. Is there a textbook on German DDC?

In March 2006 the German translation of "Dewey Decimal Classification: Principles and Application. 3rd Edition" by Lois Mai Chan and Joan S. Mitchell was published by K. G. Saur Verlag (now De Gruyter Saur) under the title "Dewey-Dezimalklassifikation: Theorie und Praxis. Lehrbuch zur DDC 22". (Further information)

WebDewey Deutsch

1. What is WebDewey Deutsch?

WebDewey Deutsch is a web application for classifying works using Dewey Decimal Classification (DDC). It replaced the MelvilClass classification tool at the end of November 2012.

2. What is the difference between the print edition and WebDewey Deutsch?

WebDewey Deutsch contains all classes, notes, Relative Index terms, texts, etc. which are also included in the print edition. Like its American counterpart WebDewey, WebDewey Deutsch also contains built numbers for frequently recurring and specific topics. Institutions etc. also have the possibility to enter their own built numbers, i.e. numbers only required by one person or institution. Comments can also be made on individual entries for specific persons or institutions. The print edition contains the dataset of DDC 22, whereas WebDewey Deutsch is constantly updated and already contains many updates to DDC 23 (cf. question 4).

3. How can I obtain a license for WebDewey Deutsch? Whom do I need to contact? What does it cost

The licensing terms and usage fees for WebDewey Deutsch can be found here. Licences are obtained via central bibliographic services at the German National Library. Please contact Uta Ackermann.

4. How often is WebDewey Deutsch updated?

WebDewey Deutsch is updated continuously. Alongside corrections of errors and the addition of register entries, there are also updates to WebDewey from the American side (such as new classes). WebDewey Deutsch is thus based on the 22nd Edition of the DDC, but already includes many updates to DDC 23.

5. Whom should I contact if I have technical questions or problems in using WebDewey Deutsch?

For all technical questions concerning the use of WebDewey Deutsch please contact Central Bibliographic Services (Uta Ackermann).

6. Whom should I contact if I have technical questions or suggestions regarding WebDewey Deutsch?

For questions and suggestions regarding WebDewey Deutsch (e.g. missing registry entries, translation errors), please contact Dr. Heidrun Alex .

Legal aspects

1. What uses of DDC are allowed once a licence has been obtained for WebDewey Deutsch and what needs to be considered?

The assignment of DDC numbers to titles is not subject to any restrictions from America. A WebDewey Deutsch licence is not necessarily required for this, it can also be done on the basis of the German or English print edition.

The part of DDC Deutsch featured in WebDewey Search has been freely available under Creative Commons BY-NC-ND 3.0 since February 2010. This means it can be used and distributed free of charge for non-commercial purposes on the condition that OCLC is named as the rights holder and that the content of the data is not processed or altered. For the first time this makes it possible to display numbers and German class names jointly without limitation - even in an organisation's own (web) applications. (Further information) Commercial providers who are interested in using DDC for their own web services must pay a fee to OCLC.

A WebDewey Deutsch license can be obtained for a fee from the German National Library. Information on WebDewey Deutsch (including usage fees) can be found here.

Zu WebDewey Search

WebDewey Search is an open access retrieval tool for resources catalogued using Dewey Decimal Classification (DDC) which replaced MelvilSearch in late November 2012.

WebDewey Search enables word-based searches (and DDC number searches) for resources catalogued using DDC. The German translation of the Dewey Decimal Classification, itself based on the 22nd edition of the DDC yet already containing many DDC 23 updates which are continuously incorporated into the DDC data base, serves as the data stock for browsing and searching.

The part of DDC Deutsch featured in WebDewey Search is freely available under Creative Commons BY-NC-ND 3.0. (Further Information)

Last update: 18.08.2017

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