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Associations and InstitutionsAnnual 

64th IFLA Conference Logo

   64th IFLA General Conference
   August 16 - August 21, 1998


Code Number: 102-158(WS)-E
Division Number: IV.
Professional Group: Classification and Indexing
Joint Meeting with: Co-sponsored by UDC/FID/BSI: Workshop "UDC"
Meeting Number: 158.
Simultaneous Interpretation:   No

The UDC at the Present Time

I.C. McIlwaine
University College London
London, UK



The workshop that we have organized for today is intended to give those who are interested an up to date view of the state of the Universal Decimal Classification, an indication of future revision plans, a demonstration of certain UDC products and an opportunity for people to address questions to a panel of speakers. After I have said a little about our general plans for the future, Vanda Broughton, the Research Assistant who has been employed by the UDC Consortium to work on the classification for the past year will speak about the revisions that she has been undertaking. Then Gerhard Riesthuis will give a demonstration of the Master Reference File. This is the authoritative database of the classification, available to anyone who wishes it, under licence for use either in their library system, or as the basis of a publication. Next, we shall have a demonstration of one of the products of that database, the CD-ROM that has been produced by the Czech Republic and finally, you will have an opportunity to ask questions of a panel of speakers from the UK all of whom are closely involved in the UDC revision process. The papers given at this workshop will be published in the 1998 issue of Extensions and corrections to the UDC, available later this year from FID at a price of 199 Dutch Guilders.

Recent history

First of all, it might be helpful if I were to fill in a little historical detail for those who are not familiar with recent events relating to the scheme. In 1992 the UDC ceased to be the property of FID and passed to the control of a newly-constituted body, the UDC Consortium. The reasons for this were firstly, because FID found itself no longer in a position to support such a costly enterprise on its own, and secondly that there was considerable debate relating to the management and revision procedures then in place, which were slow, costly and unproductive. Although the UDCC has now been in existence for seven years, there still seems to be widespread misunderstanding of the situation and many people still seem to be under the impression that FID controls the scheme, which is not the case.

The membership of the Consortium is made up of publishers of the UDC who publish the classification in world languages together, for historic reasons, with FID. The five publishers who join FID on that body at the present time are BSI - the British Standards Institution, AENOR (Asociación Española de Normalización y Certificación) - the Spanish Standards organization, CLPCF (Centre de Lecture publique de la Communauté française de Belgique), the Belgian publisher - (for historic reasons, since Otlet and LaFontaine were Belgian and the scheme originated in that country, the French edition has always been the property of Belgium, not France), Bohn Stafleu Van Loghum, the Dutch publishers of the classification and INFOSTA-NIPDOC (Information Science and Technology Association), Japan. Membership of the Consortium is open to other publishers in world languages, such as Russian or Arabic, and some broadening of membership would be very much welcomed and would, in turn, strengthen the economic situation of the classification. Full membership of the Consortium normally confers exclusive publication rights for all versions in the relevant language upon the member country.

Master Reference File

There is now one standard version of the classification, known as the Master Reference File, which will be demonstrated later, and it consists of just over 61,000 entries. This roughly approximates to what used to be known as a "medium" edition. It is updated once a year as the result of revisions, corrections and amendments published in the annual Extensions and corrections to the UDC. This is the authoritative version of the scheme, and at present it is only available in English. The long-term objective is to create a database which is multilingual.

Organizations who wish to publish a version of the classification in a language other than a "world" language, or institutions who wish to mount the classification on their own networks may apply to the Consortium for a licence to do so. This is the preferred route for many publishers issuing editions in languages that are not widely spoken, such as Czech, Polish or Estonian. A separate licence is needed for each purpose, for example, a publication in two formats, hard-copy and CD-ROM. The File can be purchased either in the ISIS format or as an ASCII text. By June 1998 the Consortium will have formulated a standard pricing policy for its licences, and these will not necessarily be more expensive than before, but will be drawn up on a more equitable basis.

In 1993 the Consortium appointed an honorary Editor-in-chief and Editorial Board. Its present practice is to commission revisions with an individual specialist or institution, rather than to rely upon a network of committees and international authorization before any change is implemented. The ten-year rule whereby the meaning of a number could not be altered for a ten-year period was also rescinded five years ago. This is not in order to hamper the international debate, but simply to speed up the process of revision which had become exceedingly slow and virtually counter-productive in the final years of FID's sole responsibility for the scheme.

Recent revision policy

In the past five years a number of substantial revisions have been undertaken and others are in the pipeline. Computer science has been completely revised and relocated in 004, a position that corresponds to the place used in the Dewey Decimal Classification. The classification for organisms in Palaeontology, Botany and Vertebrates in Zoology has been revised, and the terminology used in those classes updated. A number of smaller sections of the scheme, such as metrology and navigation, have also been revised.

Particular attention has been paid in recent years to the auxiliary tables, both general and special, and that is where the most work is being undertaken at the present time. In the Area Table revisions have been produced for (1/2) - Physiographic regions, for (43) -Germany, (47) and (57)- Eastern Europe and especially the former Soviet Union, for (68) - Southern Africa and for (94) - Australia. The special auxiliary table in class 7 has been revised, and it now accommodates modern art movements much more satisfactorily than previously and in considerable detail. There were many places in class 7 where materials were listed, frequently without any standard use of notation, despite the existence of Table 1k-03 - Common auxiliaries of materials. This situation has now been amended and the common auxiliary of materials is used uniformly throughout the class.

Extensions and corrections for 1997 carried an article questioning the value of Table 1i - Common auxiliaries of point of view (1). The user community has also been canvassed about its value in other fora, for example at the IFLA meeting last August, and through consultation with the Editorial Board. Since there has been no feedback in favour of the retention of this table, it will be cancelled in this year's Extensions and corrections and a listing will be provided to indicate how the concepts previously enumerated here can be accommodated. This, generally speaking, is in two ways - principally through the use of the colon, or through the use of another auxiliary table, either 1d - Common auxiliary of forms or a new one that is currently being constructed to list commonly recurring property terms that are of general application. You will be hearing about this in some detail in the next presentation.

This is part of a more broadly-based intention to "tidy up" the many special auxiliaries introduced by the hyphen, point nought and apostrophe, that are peppered throughout the classification and are frequently overlooked, largely because they are poorly signposted in many editions. These are to be more closely coordinated and signposted. Where they cover concepts that apply over more than one subclass, they will be combined in a clearly denoted auxiliary either at the beginning of the appropriate main class or listed among the common auxiliaries at the beginning of the classification. The probable result will be the extension of Table 1k- beyond simply materials and persons, as at present, for concepts of wider application than one class. Among the candidates for inclusion is the new Table of Common Poroperties I mentioned just now. This is a proposal to extend the hyphen auxiliaries that was made some thirty years ago, but has never, to date, been undertaken.

Finally Table 1k-05 is in the process of a thorough overhaul, with outdated concepts being removed and new ones included. The main tables have been looked at in conjunction with this auxiliary, and at all places where persons are enumerated within the compound concepts spelt out in the tables, the classification is being changed, so that the Persons facet is consistently expressed through the use of this table.

All these changes represent a move towards an increased use of faceting rather than enumeration - a facility that the notation of the UDC is makes very straightforward. This approach will make the classification much better-suited to online searching and post-coordination. The intention is to work systematically through the scheme, looking at one specific type of facet at a time and editing out anomalies. The result will be a much larger number of isolated changes in 1998's Extensions and corrections, rather than totally new tables.

Main classes which are in the pipeline for revision include the complete overhaul of Physics, and work has begun on this. We very much hope to publish the completed revision in 1999. At the same time, extensive revision of Chemistry is underway. The results of revisions in 53/54 will have a knock-on effect on the Common Auxiliary of Materials, 1k-03 and on the hyphen auxiliaries at the beginning of class 62 - engineering, both of which will probably have substantial related revisions.

Classes that are in the process of gradual revision include Chemistry, Mathematics, Religion and Astronomy. Cinema and Photography are also currently under review and new tables should be produced in either 1998 or 1999. High on the list of priorities for attention are Nuclear Science and Technology, which will be partially improved when the new Physics classification has been completed, Electronics, Education, Architecture and Building.

Revision of Medicine

A major undertaking is the revision of Class 61 - Medicine. The situation regarding this class was given careful consideration in 1993 when users were consulted about the revision procedures. At that time, serious thought was given to leaving the classification for Medicine as it was, since the majority of medical libraries all over the world had switched their allegiance, in the interests of standardization and conformity with MeSH, to the National Library of Medicine Classification. This proposal was met with dismay from the many general or scientific libraries that use UDC and have sizeable collections of medical works, without being exclusively devoted to Medicine.

It was therefore decided to revise Medicine thoroughly, and as the result of work undertaken by Professor Williamson at the University of Toronto investigating the feasibility of turning the revised Bliss Bibliographic Classification into a UDC like notation, an agreement was entered into with the Bliss Classification Association for an exchange of tables under certain conditions. (2) The first trials were carried out in 1993/94 and reports on progress have been provided annually in Extensions and corrections to the UDC. The project should be completed by 1999 and will represent an entirely new classification for Medicine in UDC, with a changed citation order focused on the Persons (e.g. Gynaecology and Obstetrics, Paediatrics, Geriatrics, etc) then the System which results in the actions such as surgery or pathology being subordinated to the appropriate part of the body, unless the item being classified is concerned with the action in general. At the present time, the first phase of work, including the allocation of notation, is completed on everything apart from the systems themselves, (i.e. approximately seven tenths of the class) and some of the remaining sections are also in a preliminary draft.

The revision of any scheme has to be undertaken at two levels, and this is what we are endeavouring to do. There is the endless task of patching up and correcting errors, together with the incorporation of newly-identified concepts on the one hand, while on the other, there is the need for a total overhaul of classes that are exceedingly out of date or unusable, such as Music or Physics in the UDC. There are also many places where the history of the scheme is still very evident. One example is in the Common auxiliaries of persons where there is excessive enumeration for Persons according to social class and civil status. Here, there are listed such historical concepts as Slaves and Slave owners, Vassals and Feudal lords, and compounded concepts that should be expressed using the numbers in the main tables in conjunction with -051, if they are needed, such as farmers, agricultural workers and industrial workers. Similarly, at 348.1/.7 there is a very detailed classification for the canon law of the Roman Catholic church, while the law of all other Christian denominations and of non-christian religions is located at 348.8. Again, in class 355/359 - Military science, there is very detailed enumeration of the various military and naval ranks, but very little for Air Forces. These are three sections of the scheme which we intend to update in this year's Extensions and corrections.

Future plans

At the present time, UDC is in a better position to move forward than it has been for some years. Its publishers are now issuing editions in a range of formats, including CD-ROM, and we shall be seeing an example of one such product later. There are proposals for the development of bilingual editions on CD-ROM, requiring agreement between two publishers, and this usually involves negotiations with the British Standards Institution, since English is almost always one of the languages required. The next logical step would be to create a multilingual Master Reference File, but this sounds more straightforward than it actually is. Although many editions of what would, in the past, have been called Medium editions, exist in a range of languages, they have all been produced at different times, so none conforms to the Master File in its present state. (As I mentioned earlier, the MRF is updated annually, while publishers rarely issue new editions more frequently than about 5 yearly - though some do issue annual supplements to their editions). Also, it is quite usual for individual language publishers to include detail that is appropriate for that particular language edition only so, for example, the French Medium Edition will have the examples spelt out in class 9 for matters of French interest, while the English edition will be illustrated by examples from English History. Similarly, it is normal for local areas to be expanded in greater detail in the individual national language editions.

A multi-lingual database is, however, one of the proposals being given very serious attention. If it comes into being, it will provide a very powerful retrieval tool as it will have the facility to switch from one language to another, using the UDC notation as a means of relating terms. It will also make the task of editing and correct usage of numbers across editions much more standard and ensure that corresponding terminology is used, but this will entail a great deal of hard work first.

This is just a quick overview of some of the things we are trying to do. We hope, by telling you in more detail about one or two of our revision projects and by demonstrating the Master Reference file and a CD-ROM developed from it you will get some idea of what is happening with the UDC. Finally, we hope that you will bring your own questions, problems and hopes for the development of the scheme before the concluding panel, so that we can continue to work to the best of our ability to produce a more up to date and useable system. We would also welcome contributions, not just today, but in the future from the user community, reporting on how they use the classification and drawing our attention to any in-house amendments and expansions that they have made which would be helpful to us in producing a more universally acceptable system.


  1. Robinson, G. "An odd point of view: some reflections on Table 1I in the UDC common auxiliaries", Extensions and corrections to the UDC, vol. 19, 1997, 29-31"

  2. Williamson, N.J. "Restructuring UDC: problems and possibilities", in Williamson, N.J. and Hudon, M. (eds.), Classification research for knowledge representation and organization: proceedings of the 5th International Study Conference on Classification Research, Toronto, Canada, June 24th -28th 1991 (FID 698), Amsterdam & London, Elsevier, 1992, 381-388. Reports on progress published in Extensions and corrections to the UDC from 1993 annually.