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Many information professionals working in small units today fail to find the published tools for subject-based organization that are appropriate to their local needs, whether they are archivists, special librarians, information officers, or knowledge or content managers. Large established standards for document description and organization are too unwieldy, unnecessarily detailed, or too expensive to install and maintain. In other cases the available systems are insufficient for a specialist environment, or don't bring things together in a helpful way. A purpose built, in-house system would seem to be the answer, but too often the skills necessary to create one are lacking. This practical text examines the criteria relevant to the selection of a subject-management system, describes the characteristics of some common types of subject tool, and takes the novice step by step through the process of creating a system for a specialist environment. The methodology employed is a standard technique for the building of a thesaurus that incidentally creates a compatible classification or taxonomy, both of which may be used in a variety of ways for document or information management. Key areas covered are: What is a thesaurus? Tools for subject access and retrieval; what a thesaurus is used for? Why use a thesaurus? Examples of thesauri; the structure of a thesaurus; thesaural relationships; practical thesaurus construction; the vocabulary of the thesaurus; building the systematic structure; conversion to alphabetic format; forms of entry in the thesaurus; maintaining the thesaurus; thesaurus software; and; the wider environment. Essential for the practising information professional, this guide is also valuable for students of library and information science.

Classification is a crucial skill for all information workers involved in organizing collections. This new edition offers fully revised and updated guidance on how to go about classifying a document from scratch. Essential Classification leads the novice classifier step by step through the basics of subject cataloguing, with an emphasis on practical document analysis and classification. It deals with fundamental questions of the purpose of classification in different situations, and the needs and expectations of end users. The reader is introduced to the ways in which document content can be assessed, and how this can best be expressed for translation into the language of specific indexing and classification systems. Fully updated to reflect changes to the major general schemes (Library of Congress, LCSH, Dewey and UDC) since the first edition, and with new chapters on working with informal classification, from folksonomies to tagging and social media, this new edition will set cataloguers on the right path.

Library of Congress Subject Headings (LCSH) are increasingly seen as 'the' English language controlled vocabulary, despite their lack of a theoretical foundation, and their evident US bias. In mapping exercises between national subject heading lists, and in exercises in digital resource organization and management, LCSH are often chosen because of the lack of any other widely accepted English language standard for subject cataloguing. It is therefore important that the basic nature of LCSH, their advantages, and their limitations, are well understood both by LIS practitioners and those in the wider information community. Information professionals who attended library school before 1995 - and many more recent library school graduates - are unlikely to have had a formal introduction to LCSH. Paraprofessionals who undertake cataloguing are similarly unlikely to have enjoyed an induction to the broad principles of LCSH. This is the first compact guide to LCSH written from a UK viewpoint.

Summary

Even in the 21st century you won't encounter many libraries organized by a faceted classification, yet faceted classification is probably the most important development in classification theory of the last hundred years.

Facet analysis has influenced the structure and development of all the general classification schemes, and today there are few classifications that don't show some evidence of that influence. The identification of precise relationships between classes, the use of synthetic notations, and ideas such as facet indicators, the consistent application of citation order, and schedule inversion all come from faceted classifications, and all are to be found in the more recent revisions of (originally) nonfaceted classifications.

Because the methodology of faceted classification (what we shall call facet analysis) provides very clear principles for the organization of concepts, first into categories and then into a linear sequence, it produces very predictable and robust structures. These structures are particularly good at accommodating compound subjects at any level of complexity, and their internal logic makes them very suitable for use in automated systems. The much better structure of a faceted scheme explains why the general systems of classification have been keen to import these methods into their own revision processes.

The nature of faceted classification

Before we go further with the discussion of faceted classification, let's deal with some common misapprehensions about it.

Firstly, although there are classification schemes that are faceted, faceted classification itself is not a particular scheme or system, but rather a method for making a classification. You can see elements of faceted structure in schemes that are not themselves completely faceted. UDC in particular has some completely faceted main classes now, and some of the recent revisions of DDC have sections that are plainly based on facet analysis. As we look at the various aspects of facet analysis, we'll see illustrations from a range of schemes, not just the fully faceted ones.

There is also quite a widespread belief that any scheme with analyticosynthetic features is a faceted scheme. This is particularly the case among computer scientists who've become interested in classification, and is also sometimes encountered in the US literature. Most schemes allow some measure of classmark building, but this doesn't make them faceted schemes.

Summary

So far we have looked at a number of aspects of the theory of classification, at the central activity of applying particular schemes, and, of course, at how the two are related. Another important factor is the management of the scheme, both at the editorial level and in the local situation.

The management and maintenance of schemes

It's important for the institutional user to be aware of the arrangements in place for the upkeep of the classification system. The classification is a major tool in the organization of the library (more important than is generally acknowledged) and you need to be assured that it will be maintained and kept current, and that its editors will respond to the changing needs of collections and to developments in technology. We'll consider the different publication formats in some detail below, but the broader concerns of the currency and stability of the classification are independent of any particular version.

The general management of classifications

Most schemes are managed by an institution or organization that ensures its continued existence. The larger and more stable this organization, the more likely it is to support the classification well. The biggest classifications, such as DDC and LCC, have a considerable machine behind them that can accommodate the general running of the classification, its publication, the dissemination of information to users, the promotion of the scheme, the creation of training materials, the provision of bibliographic services, and research into the theory and applications of classification. The availability of all these secondary features can make the classification more attractive to the end-user and greatly enhance its usefulness. All of them additionally serve to create a sense of community among users and to promote loyalty to the system – they're all good public relations exercises.

Revision and maintenance

The most important of these operations, as far as the classification itself is concerned, is the ongoing upkeep of the scheme, particularly the revision of the scheme to accommodate new subjects. It's absolutely essential to have robust mechanisms for identifying and incorporating new topics in the literature, and for informing users about such additions and amendments. The reverse process, the pruning of obsolete terms, and, in some cases, removing biased or politically incorrect terminology and structures, needs also to be in place.

Summary

So far we've looked at why we need to organize documents, at some of the fundamental problems in the process of organization and at how to decide on the subjects of documents. In the next part of the book we shall look at the tools which we need to bring those two operations together in the formal processes of classification and subject cataloguing.

Natural language indexing and searching

Indexing, classifying and the subject description of documents are on the whole very labour-intensive (and intellectually arduous) processes. This is one of the reasons why abstracting and indexing services, and bibliographic databases, are so very expensive to subscribe to. An obvious question is whether we really need to use complicated artificial systems of classification and indexing to describe documents. Why not use the language of our everyday speech, since surely this would make the assignment of the keywords much quicker and easier? And the titles of documents or the text itself could provide us with the terms that are needed for indexing. In any event, whatever cataloguers do, the endusers will choose search terms out of their own heads, and not from a classification scheme which they have never seen or heard of.

On the face of it, it would appear to be much easier to use this natural language approach to index documents, both for the initial indexing, and also for the retrieval process, particularly where machines can help with the process. When automation began to be used more widely in libraries in the 1970s it was generally thought that the immense power of the computer to scan the whole of a large store of information in a few seconds would obviate the need for all this expensive and exhausting brain work. Free-text searching and natural language indexing became the norm, classification and indexing were seen as moribund and pointless, and the study of classification disappeared from many library school curricula during the 1970s and 1980s.

Initially, the advent of the world wide web reinforced this attitude, since even the information illiterate can search and retrieve masses of information using only natural language. On the other hand, any acquaintance with web searching will have shown you how inefficient natural language searching can be, because the web is an information store so large that the juggernaut techniques of the early automated systems cannot solve the problems that searchers encounter.

Summary

When the content of the document is decided, and the concept analysis made, the time has come to translate this into the specific language of your chosen scheme. We shall examine several of the general schemes in detail, but first we are going to look at the general appearance and features of a classification scheme, and how to go about using one.

For the beginner classifier one of the greatest difficulties lies in simply navigating the scheme. This is because at the outset you have little idea of the overall order and structure of the scheme, and no expectation of what you might find in terms of the vocabulary or level of detail. This feeling is multiplied if you're not familiar with any scheme, since the general idea of which topics belong in which discipline tends to be common to them all – what we call consensus – and knowledge of one system is helpful in second guessing the location of classes in another.

Don't therefore be alarmed, if, when you start cataloguing, you spend a long time looking for things – this is quite usual and you will soon speed up when you get to know the scheme better.

In this chapter we'll look at the various parts of a published schedule, and examine some ways to help you find your way round a big scheme.

The composition of the classification scheme

A classification scheme consists of two parts: the systematic display (or schedules) and the index. Both are important in the application of the scheme, and you should examine both carefully when classifying.

The index

We'll begin with the index, because this is where, as a novice, you will have to start.

In Chapter 4 we discussed how an aspect classification scatters the various aspects of an entity, using the rabbit as an example. The index is very important because it is where the distributed relatives are brought together in an aspect classification and where you find out all the possible places to put a book about rabbits. Although you might make an educated guess at where your subject occurs, you will need the index to discover for certain the various places where your subject is provided for. If you go straight to the schedule you may miss a better location for your document.

Summary

The Library of Congress Classification (LCC) is unusual among the general schemes in that it was originally a scheme intended for a single library, with no expectation that it would ever be used in any others. Today it is one of the two dominant classification schemes, certainly in the Western world (the other being the Dewey Decimal Classification). It's a popular choice for academic libraries, particularly university libraries, but also for specialist collections in some subjects. It is also used in one British public library (Edinburgh), but is more common in public libraries in the United States.

Undoubtedly the management advantages of using LCC have influenced modern libraries. The free availability of records on the Library of Congress catalogue, and big union catalogues which include LCC records (such as COPAC in the UK), as well as the excellent bibliographic services offered by the Library of Congress, are very attractive at a time when most libraries regard copy cataloguing as the norm, and do little original cataloguing work.

History of the Library of Congress Classification

The Library of Congress itself was founded by order of Congress in January 1802, by ‘An Act concerning the Library for the Use of both Houses of Congress’. This provided for a room for the collection of 740 books (which had been purchased by Senator Samuel Dexter in the previous year), the establishment of rules for the use of the Library, and the appointment of the first librarian, John Beckley. In April 1802 he was able to issue the first catalogue, in which the shelf arrangement is recorded: this was by size.

In 1812 a subject approach was applied for the first time, the classification used being that of the Library Company of Philadelphia, an independent research library. This classification was based on an adaptation of Bacon's system used in the Encyclopédie of Diderot and d'Alembert. The Library of Congress used only 18 of Philadelphia's 31 main classes, and within each class the books were subdivided by size and arranged alphabetically.

In 1814 the Capitol, including the Library of Congress, was burned by the British, and most of the collection was lost. Thomas Jefferson offered to sell Congress his own library, which was organized by his own system of 44 main classes, again based on Bacon/d'Alembert.

Summary

The Decimal Classification, devised by Melvil Dewey, is the oldest of the classification schemes still in common use, and by far the most widely used. It is the scheme that most non-librarians are familiar with, and indeed few of them will be aware of any other library classification.

Although it is the oldest scheme, I have chosen to place it after the Library of Congress Classification, since the latter is a somewhat simpler scheme to apply and doesn't show the complexity of operation that DDC now does. DDC is an enumerative scheme with analytico-synthetic features and as such sits quite neatly between LCC and UDC.

DDC is used all over the world and in all types of libraries, although most British readers will think of it as the ‘public library’ classification, since there is only one British public library which doesn't use it. It's also the predominant classification in school libraries. As it becomes more detailed and with more facilities for number building, it has increased in popularity as a scheme for academic libraries. Despite the fact that its publishers claim it to be used by 20% of special libraries in the US, it's probably not sufficiently specific for many special libraries or those with a great deal of technical material.

DDC is quite exceptionally well supported institutionally, and this is undoubtedly one of the reasons for its tremendous success. DDC classmarks appear on all Library of Congress catalogue records, and its editorial office is located there, which enables close monitoring of trends in documentation and the emergence of new topics. It has for several decades been the classification used in the British National Bibliography, and it was adopted by the British Library for the organization of the Reading Room collections at the new library when it opened.

OCLC, the Online Computer Library Center, a not-for-profit organization, publishes the classification, and maintains WorldCat, a two billion item database of records, which include DDC data, from 10,000 libraries across the globe. OCLC also undertakes research and has a number of interesting projects in the area of vocabulary management and automatic indexing, some of which are concerned with developing new roles and applications for the classification.

Formal maintenance and revision of the classification is undertaken by the editor-in-chief and assistant editors under the guidance of the Editorial Policy Committee.

Summary

In the previous chapter we considered how to express the complete content of a document by using more than one heading. Most of the headings used to illustrate Chapter 12 were pre-coordinated headings, combining more than one concept, such as Ecclesiastical embroidery or Wildlife conservation. In fact it's quite hard to find headings that are not pre-coordinated in this way.

There is another way for you to combine concepts in LCSH, and that is through the use of structured headings. A structured heading, like a pre-coordinated heading, has two or more concepts combined, but instead of merging them into a natural language phrase, the conceptual structure is displayed using dashes, rather as we've done with the concept analyses or subject strings.

Examples

Bumblebees– –Fiction

Archipelagoes– –Guadeloupe

Jigsaw puzzles– –Collectors and collecting– –United States

Cucumbers– –Bibliography

Tightrope walking– –France– –Case studies

Chickens in art– –Exhibitions

Dentures– –Drama

The normal practice when typing out or entering structured headings is to use a double dash (Bumblebees– –Fiction). This is to distinguish the structured heading from one that simply contains a hyphen (Animalwater relationships or Sugar-beet web-worm).

Structured subject headings fall into three broad categories:

Summary

Classification is everywhere. We classify birds and animals, languages and ethnic groups, stars, volcanoes, minerals and clouds, wine and blood, and colours and roses. We classify diseases, occupations and social status; the size of notepaper (grand eagle, elephant and pott); the dimensions of icebergs (small, bergy bits and growlers); and brandy (mellow, pale and superior).

It is natural to the human mind to classify, and essential if we want to make sense of the world, which is full of unique creatures and objects. Each day we encounter hundreds of these which we might never have seen before, but the process of classification allows us to recognize a street lamp, a dog, a magazine, a train, sandwiches for lunch, bananas, music on the radio, and make sense of those things. We don't need to investigate and learn about every new event in our lives because most of them conform to other objects and phenomena in our personal experience; we know what to expect of a dog or a banana, since they are similar to dogs and bananas we already know.

Everybody can and does classify, and if we spend so much time and energy classifying the world about us, it is natural to attempt to organize our stores of information about the world. It's necessary, too, to have systems for managing stored information in a way that allows us to find it again – systems that use our human classificatory skills to organize, to match, to predict and to interpret.

This is a book about some of the systems which people have created for organizing information. It also examines the problems we face in sorting out the relationships between subjects, and imposing order on chaos. It's about the nature of knowledge as it is found in books and other information-carrying media. It is also first and foremost a book about how to classify. The emphasis throughout is on the activity of classification rather than the theory, the practical problems of the organization of collections, and the needs of users.

You don't need any knowledge or experience of classification to use this book. It's intended for beginners, for students, and for people working in libraries who have never had any formal education or training in classification or subject cataloguing.

Summary

As we saw in the previous chapter, it's very straightforward to construct LCC call-marks. In most cases, the subject part of the call-mark is lifted from the schedule without any alteration. The only real intellectual work for the classifier is the creation of the Cutter number, deciding whether it should be for the author or for another aspect of the work, and contriving a number that will fit in with the existing sequence. Very often, even this isn't required, as LCC is so fond of lists that it offers thousands of ready-made subject Cutters.

There are, however, some areas where more detail can be achieved by a limited sort of number building, and you normally do this by using tables.

Tables in LCC

LCC is quite unlike any other classification in its use of tables. In most schemes you would expect to find commonly occurring concepts, such as place, time or form, provided for in a general table to be used throughout the system. This is what happens in DDC and UDC, and of course has its equivalent in LCSH in the free-floating subdivisions.

In LCC every table is special to the place where it is applied. Even where a table is used frequently in a particular main class (as happens in Class H, Social sciences) it can still be used only where the instructions permit. For example, in the part of the schedule shown in Figure 16.1, Table 21 can be used to expand the classes for Bisons (sic), Edible birds’ nests, Edible caterpillars, Edible snails and Kangaroos, but Table 23 must be used for Goats. You can't use a table to expand Rabbits since there is no instruction to do so, but some enumerated classes are provided.

This means that adding notation from tables is a laborious business since there is no single consistently used table for common concepts, nor is there any mnemonic value in the notation, since it hardly ever remains the same in two different classmarks.

In the online version of LCC the tables are very easy to use: when you click on the link to a table it pops up and inserts itself into the schedule, working out the numbers for you.

Summary

When you go into a library you usually have one of two purposes in mind. In some cases you may be looking for a particular book or journal, report or recording. You know that you want the latest Jeffrey Archer novel, an article about global warming in last week's New Scientist, or the film version of Romeo and Juliet directed by Zeffirelli. Generally you have enough information about the author, title or source of the item for the library staff to help you locate it. Even if you are lacking some details, you know that you don't want the latest Barbara Cartland novel, a piece on global warming in last week's Woman's Weekly, or the film version of Romeo and Juliet directed by Luhrmann. Finding what you want in this case is called known item retrieval, because you already know about the specific work that will meet your needs. Normally the item can be traced using the author's name or the title of the work, or some combination of elements from these.

In many other cases you don't want any particular item, but you do want some information about global warming, or 17th-century drama, or how to grow petunias. You're not bothered who wrote the book or article, what it is called, or who published it, as long as it contains relevant information. The library may have lots of material that will meet your information needs, but none of it can be retrieved using an author, title or publisher, because these are not known.

In order for anyone to find material about a given topic it is essential that the individual books and other items in the collection have had their subject content identified and recorded. Looking for information based on the content of documents is known as subject retrieval, subject searching, or subject access. In the majority of libraries and information services this formal identification of the subject content, and subsequent searching, is done by using a classification scheme and/or a system of subject headings.

In this book we shall be looking at some of the problems that arise when we try to organize documents by their subjects, and how classification schemes and subject headings are applied to the items in a collection in order for readers (and library staff) to find what they want in the most effective way.

Summary

In the last chapter on alphabetical subject access we looked at some of the general considerations of alphabetical subject work and the problems (and their solutions) that arise when we use words as the basis of retrieval. While it's perfectly possible to develop an in-house subject indexing system based on the concept analyses for individual documents, the intellectual effort involved and the high cost of maintenance required mean that most libraries opt to use a published standard. In the vast majority of cases that standard will be the Library of Congress Subject Headings (LCSH). During the last twenty years of the 20th century many academic libraries in the UK began to use LCSH, even if they were not using the Library of Congress Classification, and it is used, in English in 24 national libraries, and in 12 others in translation. This is in addition to its long-established use in the United States and Canada. The only other set of English language general subject headings in common use is Sears’ List of subject headings for a small library, which, as the name suggests, is much less extensive than LCSH. While many countries have their own national standards for subject headings (such as Nuovo Soggettario in Italy), others use adaptations or modifcations of LCSH, such as the Canadian Répertoire de vedettes-matière.

What is LCSH?

LCSH is an alphabetical list of the headings that are used in the subject catalogues of the Library of Congress, together with ‘thesaural’ crossreferences that enable classifiers to find other appropriate headings. A typical section of LCSH looks something like this:

Umbrellas (May Subd Geog)

UF Bumbershoots

Umbrellas and parasols [Former Heading]

BT Weather protection — Equipment and supplies

NT Parasols

Umbrellas– –Tariff

USE Tariff on umbrellas

Umbrellas and parasols

USE Parasols

Umbrellas

NT Umbrella industry

Umbrellas and parasols in art

USE Parasols in art

Umbrellas in art

Umbrellas in art (Not Subd Geog)

UF Umbrellas and parasols in art [Former Heading]

When we come to the section on practical application of LCSH we'll look in detail at the layout, and at what the different cross-references and typographical variations mean, so you don't need to worry about these at this stage.

Summary

Synthesis and number building in Dewey

DDC was initially an enumerative scheme; the tables were introduced much later in its history, as were other means of creating numbers for compound subjects. Because of this it has no general mechanisms for handling compound subjects, but only ‘local’ provision in some classes. For example, under Cooking of specific foods, 641.63-.69, you can add numbers for plant crops and domesticated animals:

641.63.-.67 Cooking food from plant crops and domesticated animals Add to base number 641.6 the numbers following 63 in 633-637, e.g. legumes 641.6565, meat 641.66

Unfortunately you can't apply this principle to another part of the schedule except where there are specific instructions to do so, however useful that might be. The standard subdivisions in Table l are the only parts of the scheme that can be added to another classmark as needed. The result is that some parts of the system can achieve high levels of specificity and subject description, while other parts can provide only a broad level classification.

Mechanics of number building

Number building in DDC normally takes one of three forms:

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Essential Thesaurus Construction

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21 - Faceted classification

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22 - Managing classification

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10 - Controlled indexing languages

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Bibliography and further reading

Glossary

6 - Types of classification scheme

14 - Classification scheme application

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15 - Library of Congress Classification 1: basic classmark construction

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Contents

5 - The classification scheme: internal structure

17 - Dewey Decimal Classification 1: general properties and basic numbers

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13 - Library of Congress Subject Headings 2: structured headings

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1 - Introduction

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16 - Library of Congress Classification 2: use of tables

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2 - The need for classification

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12 - Library of Congress Subject Headings 1: basic headings

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18 - Dewey Decimal Classification 2: number building

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