Essential classification

Broughton Essential Classification 2nd edn_textbook 04/06/2015 18:00 Page 1

LASSIFICATION IS A crucial skill for all information workers involved in
organizing collections. This new edition of Broughton’s respected text offers
fully revised and updated guidance on how to go about classifying a
document from scratch.

C

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. Key areas covered
are:
the need for classification
the variety of classification
the structure of classification
working with informal classification
management aspects of classification
classification in digital space.

“Essential classification might
be optimised for the LIS
student or novice
practitioner, but others
engaging with classification
and subject indexing are
likely to find this book an

invaluable working tool. It is,
as the title predictably
suggests, essential.”
Library Review

This guide is essential reading for library school students, novice cataloguers and all
information workers who need to classify but have not formally been taught how. It
also offers practical guidance to computer scientists, internet and intranet managers,
and all others concerned with the design and maintenance of subject tools.

ISBN 978-1-78330-031-0

Essential
Classification
SECOND EDITION

VANDA BROUGHTON

Vanda Broughton MA DipLib is Professor of Library & Information Studies in the
Department of Information Studies at University College London (UCL), and teaches
on the MA LIS Programme. She has taught, written and led training courses on
classification for many years. She is Editor of the Bliss Bibliographic Classification 2nd
edition and Associate Editor of the Universal Decimal Classification. She is the author
of two other Facet titles, Essential Library of Congress Subject Headings and Essential
Thesaurus Construction.

SECOND EDITION

■
■

■
■
■
■

About the previous edition:

Essential Classification

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 about 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.

Facet Publishing
www.facetpublishing.co.uk
ISBN 978-1-78330-031-0

VA N D A B R O U G H T O N


Broughton Ess class 2e TEXT PROOF 05_Broughton prelims.qxd 04/06/2015 18:09 Page i

Essential
classification
SECOND EDITION

Broughton Ess class 2e TEXT PROOF 05_Broughton prelims.qxd 04/06/2015 18:09 Page ii


Broughton Ess class 2e TEXT PROOF 05_Broughton prelims.qxd 04/06/2015 18:09 Page iii

Essential
classification
SECOND EDITION

Vanda Broughton


Broughton Ess class 2e TEXT PROOF 05_Broughton prelims.qxd 04/06/2015 18:09 Page iv

© Vanda Broughton 2004, 2015

Published by Facet Publishing
7 Ridgmount Street, London WC1E 7AE
www.facetpublishing.co.uk

Facet Publishing is wholly owned by CILIP: the Chartered Institute of
Library and Information Professionals.

Vanda Broughton has asserted her right under the Copyright, Designs and
Patents Act, 1988, to be identified as author of this work.

Except as otherwise permitted under the Copyright, Designs and Patents
Act 1988 this publication may only be reproduced, stored or transmitted
in any form or by any means, with the prior permission of the publisher, or,

in the case of reprographic reproduction, in accordance with the terms of
a licence issued by The Copyright Licensing Agency. Enquiries concerning
reproduction outside those terms should be sent to Facet Publishing,
7 Ridgmount Street, London WC1E 7AE.
First published 2004
This second edition 2015

British Library Cataloguing in Publication Data
A catalogue record for this book is available from the British Library.
ISBN 978-1-78330-031-0

Text printed on FSC accredited material

Typeset in 11/14pt Aldine 721 and Humanist by Facet Publishing.
Printed and made in Great Britain by CPI Group (UK) Ltd,
Croydon, CR0 4YY.


Broughton Ess class 2e TEXT PROOF 05_Broughton prelims.qxd 04/06/2015 18:09 Page v

Contents

Acknowledgements............................................................................ix
1

Introduction ................................................................................1

2

The need for classification ..........................................................5

3

First principles of classification...................................................7
Grouping – ordering – compound subjects – problems of
linear order – citation order – distributed relatives

4

The variety of classification: systems and structures ...............13
Scientific classifications – taxonomies – tree structures – folk
classifications – bibliographic classifications – aspect
classifications

5

The classification scheme: internal structure..........................23
Grouping of concepts – hierarchy – semantic relationships –
syntactic relationships – pre-coordination

6

Types of classification scheme ..................................................33
Enumerative classifications – ‘top-down’ classifications –
analytico-synthetic classifications – faceted classifications –
‘bottom up’ classifications

7

Order in the classification scheme ...........................................41

Main classes – phenomena classes – main class order – schedule
order and filing order – general-before-special – literary warrant
and educational consensus – notation – notational symbols –
expressiveness – mnemonics – flexibility and hospitality


Broughton Ess class 2e TEXT PROOF 05_Broughton prelims.qxd 04/06/2015 18:09 Page vi

VI

ESSENTIAL CLASSIFICATION

8

Content analysis 1: document description ..............................57
The problem of ‘aboutness’ – where to look for content –
constructing the document description – sought terms –
common categories of terms (place, time, form, persons) –
ordering the description

9

Content analysis 2: practical constraints .................................75
Broad and close classification – specificity and exhaustivity –
difficult subjects – biography – primary texts

10

Controlled indexing languages .................................................89
Natural language indexing and searching – the meaning of

words – synonyms and homonyms – sought terms –
controlled indexing languages – standards for document
description

11

Word-based approaches to retrieval .......................................97
Subject heading lists – thesauri – alphabetical arrangement –
synonymy and related matters – form and structure of
subject headings – modern developments in subject indexing

12

Library of Congress Subject Headings 1: basic
headings...............................................................................111
History of LCSH – literary warrant – Cutter’s Rules and the
form of entry – uniform headings – valid headings – thesaural
cross references – selecting headings – multiple-headings –
entering headings onto a record

13

Library of Congress Subject Headings 2: structured
headings...............................................................................131
Topical subdivisions – pattern headings – geographical
subdivisions – free-floating subdivisions – name headings

14

Classification scheme application...........................................153

Appearance of classification schemes – the index – the
schedules – classes – captions and headings – schedule layout
– scope notes – instructions


Broughton Ess class 2e TEXT PROOF 05_Broughton prelims.qxd 04/06/2015 18:09 Page vii

CONTENTS

VII

15

Library of Congress Classification 1: basic classmark
construction ........................................................................161
History of LCC – general principles – literary warrant –
enumerative classification – alphabetization – notation –
practical classification – Cutter numbers

16

Library of Congress Classification 2: use of tables ................183
Tables – content of tables – how tables work – geographical
subdivision – form subdivision – subject subdivision – tables
for classes using Cutter numbers – tables embedded in the
schedules – tables used in combination

17

Dewey Decimal Classification 1: general properties and

basic numbers .....................................................................199
History DDC – structure of DDC – hierarchy – notation –
compound subjects and number building – citation order –
preference order – practical classification – using the relative
index – first-of-two rule and the rule of three –
approximating the whole

18

Dewey Decimal Classification 2: number building ................219
Use of tables – standard subdivisions – place and time –
persons – adding notations from the main schedules

19

Universal Decimal Classification 1: general properties
and basic number building .................................................241
History of UDC – structure of UDC – an analytico-synthetic
classification – notation – symbols – expressiveness –
schedule display – main tables – number-building – the colon
– the plus sign – the oblique stroke

20

Universal Decimal Classification 2: auxiliary tables ..............265
Systematic auxiliary tables – language, form, place, ethnicity,
time, materials, persons – special auxiliaries – language and
literature

21

Faceted classification ..............................................................299
History of facet analysis – building blocks of classification –


Broughton Ess class 2e TEXT PROOF 05_Broughton prelims.qxd 04/06/2015 18:09 Page viii

VIII

ESSENTIAL CLASSIFICATION

fundamental categories – arrays – relationships between
terms – citation order – schedule order – inversion –
notation – facet indicators – retroactive notation
22

Managing classification ...........................................................327
Management and maintenance of schemes – revision – costs
of classification – copy cataloguing and outsourcing – print
and electronic format – choosing a classification – general
versus special schemes

23

Classification in digital space ..................................................339
Classification as models – electronic forms of classifications –
classifying digital material – information architecture –
classification for online browse and search – folksonomy –
automatic classification – visualization tools – faceted
classification – the semantic web

Glossary ...........................................................................................375
Bibliography and further reading...................................................399
Index .............................................................................................407


Broughton Ess class 2e TEXT PROOF 05_Broughton prelims.qxd 04/06/2015 18:09 Page ix

Acknowledgements

I should like to thank my former colleague John Bowman who
originally proposed to Facet Publishing that I should write this book.
He also read all the drafts of the first edition, and made many
pertinent and helpful comments and suggestions.
I must also acknowledge the part played by the students of the
Department of Information Studies, University College London;
their journeys through the difficult terrain of classification have
highlighted the rocks and the hard places, and taught me where
beginners most need help and guidance.
My thanks to the editors and rights holders of the general schemes
of classification for their assistance and permission to use excerpts
from those schemes: to the Editor-in-chief, and Chair of the UDC
Consortium, for the Universal Decimal Classification, to the Editor
and OCLC for the Dewey Decimal Classification, to the Library of
Congress for Classification Web, and to the Bliss Classification
Association for the Bliss Bibliographic Classification Second
Edition. I should mention in particular the previous and current
editors-in-chief of the UDC, Ia McIlwaine and Aida Slavic, with
whom I have worked closely in recent years. Special thanks are owed
to the late Jack Mills, Editor of BC2, my colleague, teacher and

mentor for almost 40 years.
Excerpts from the Dewey Decimal Classification are taken from the
Dewey Decimal Classification and Relative Index, Edition 23 which is
Copyright 2011 OCLC Online Computer Library Center, Inc. DDC,
Dewey, Dewey Decimal Classification and WebDewey are registered
trademarks of OCLC Online Computer Library Center, Inc.
I would also thank the following publishers for permission to
reproduce title pages and other elements from their books:


Broughton Ess class 2e TEXT PROOF 05_Broughton prelims.qxd 04/06/2015 18:09 Page x

X

ESSENTIAL CLASSIFICATION

Figure 8.1 Birds of coast and sea, by Bruce Campbell, illustrations by
Raymond Watson (reproduced by permission of Oxford University
Press).
Figure 8.2 Hoping for a hoopoe by John Updike (reproduced by
permission of Victor Gollancz, a division of The Orion Publishing
Group).
Figure 8.5 Saints: the chosen few by Manuela Dunn-Mascetti
(reproduced by permission of Macmillan Publishing).
Figure 8.6 Bird behaviour by Louise Dawson and Mike Langman
(reproduced by permission of Hamlyn).
Figure 8.7 The British Museum book of cats: ancient and modern by Juliet
Clutton-Brock (reproduced by permission of the British Museum
Company Ltd).
Figure 8.8 Railway architecture of Greater London by Rodney Symes and

David Cole (reproduced by permission of Osprey Publishing Ltd).
Figure 8.10 First aid for dogs: what to do when emergencies happen by
Bruce Fogle (reproduced by permission of the Penguin Group
(UK)).
Figure 9.2 Bee hives of the ancient world, by Eva Crane and A. J. Graham
(reproduced by permission of the International Bee Research
Association (www.ibra.org.uk)).
Figure 20.1 Domus Anguli Puensis ((Latin for The House at Pooh Corner)
©1980 Egmont Books Ltd, London and used with permission).
Every effort has been made to trace the holders of copyright in the title
pages reproduced. If there are any queries please contact Facet
Publishing.
Vanda Broughton


Broughton Ess class 2e TEXT PROOF 05_Broughton prelims.qxd 04/06/2015 18:09 Page 1

1 Introduction

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.


Broughton Ess class 2e TEXT PROOF 05_Broughton prelims.qxd 04/06/2015 18:09 Page 2

2

ESSENTIAL CLASSIFICATION

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. It is based very
largely on the cataloguing and classification module of the MA in
Library and Information Studies taught at the Department of
Information Studies, University College London, although most of
the practical exercises are new.
We’ll proceed step by step through the basics of organizing a
collection, the problems of linear arrangement, and the difficulties
posed by complicated subjects and their interrelationships. We’ll look at
how to decide on the subject of a document, and how the needs of
different groups of users can affect that decision. We shall learn how to
apply those systems that are frequently encountered in libraries – the
Dewey Decimal Classification (DDC), the Universal Decimal
Classification (UDC) and the Library of Congress Classification (LCC),
as well as Library of Congress Subject Headings (LCSH).
A major difficulty in writing a textbook about classification is that the
book to be classified should always be to hand, and clearly the reader
can’t be expected to have access to every title mentioned. For the most
part, therefore, the works chosen have titles that indicate plainly their
content. The chapters on content analysis deal with less straightforward
situations and provide a strategy for coping with these.
This book is principally distinguished from other current books about
classification by the very large number of practical exercises and activities,
but nobody learned to classify documents by any means other than doing it,
and certainly not by reading about the philosophic principles of X or Y
classification. If you work through all the exercises you should acquire a
knowledge of the basic workings of the different schemes covered. No
preference for any particular scheme is intended, but I hope readers will gain
a sense of the characteristics of these classifications and of the different
situations where each would be an appropriate choice as a subject access tool.
All of the titles included are real books, or occasionally journal

articles or conference papers. They have been taken from the
catalogue of the Library of Congress, and COPAC, the merged
catalogue of 80 large UK and Irish academic and research libraries,
including the British Library. The occasional article has been selected
from Zetoc, the British Library’s electronic table of contents. With a


Broughton Ess class 2e TEXT PROOF 05_Broughton prelims.qxd 04/06/2015 18:09 Page 3

INTRODUCTION

3

very few exceptions the titles are all recent publications.
The great majority of the examples are books, but the techniques
learned are equally applicable to non-book resources, to non-print
materials, and to resources other than text. There is no difference in the
analysis of subject content of different media, since the only thing under
consideration is the ‘aboutness’ of the resource. On that basis
classification schemes can be (and are) used to organize resources in any
format, print and electronic, text and image, sound and vision and
multimedia, objects and data, and representations or surrogates of all of
these. Throughout the text I’ve used the terms book, document, item or
work when referring to the things to be classified, but any sort of
information carrier is always implicit in those terms.
Similarly, I have not made any great distinction between the print and
electronic versions of the different schemes, and I’ve used the online
versions throughout in compiling the book. For the most part, there is
very little difference in the appearance of paper and online
classifications, except that online you normally see only a limited

section of the scheme. For that reason some of the figures are based on
the print display, simply because it provides a broader view of the
structure of the classification. The chapters on the individual schemes
each contain a section on the electronic versions to explain the search
mechanisms, and to cover any minor differences.
Although the main stress is on things practical, it’s impossible to
understand the rationale behind classifications without some
introduction to the theory, and the early chapters provide an outline of
the principles of bibliographic classification. This, and the practical
application of schemes, uses a technical vocabulary which you need to be
familiar with. Technical terms are explained in the text, but for
convenience they are also gathered together in a glossary. Terms included
in the glossary are in bold typeface in the text, at least on the first few
occasions of their appearance.
After reading the book and trying the exercises, you should have all
you need to carry out basic classification, but I’ve included a brief
bibliography, should you become interested and want to find out more,
as I did as a student over forty years ago. I still find it the most
intellectually stimulating part of the professional curriculum, and also
the most intriguing and the most entertaining. I hope you will be
stimulated and intrigued, and at least a little entertained by it.


Broughton Ess class 2e TEXT PROOF 05_Broughton prelims.qxd 04/06/2015 18:09 Page 4


Broughton Ess class 2e TEXT PROOF 05_Broughton prelims.qxd 04/06/2015 18:09 Page 5

2 The need for classification

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

Broughton Ess class 2e TEXT PROOF 05_Broughton prelims.qxd 04/06/2015 18:09 Page 6

6

ESSENTIAL CLASSIFICATION

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.
Until the last quarter of the 19th century libraries did not use
classification schemes in the way that we do today. Certain sections of
the library (or certain bookcases or shelves) might be assigned to
particular subjects, but this was usually in a fairly broad system of
subject arrangement, and the notations, if any, that were applied to
books related to their position on the shelf rather than to their subject
content. At that time it was more common for libraries to operate on the
basis of closed access: that is to say readers were not permitted to
browse among the stock, but had books fetched for them by library staff.
Identifying books on a particular subject would have depended on the
librarian’s knowledge of the book stock, and there was usually no
systematic means of searching for a book by subject.
Around the end of the 19th century libraries increasingly moved
towards systems of open access, where users were able to go to the
shelves and select books for themselves. It then became necessary to
have ways of organizing the collections that were clear and
understandable to users. Librarians at the time decided that the most
helpful way to arrange their books was by subject, and this has remained
the basis on which almost every library is managed to this day.

At about the same time, librarians became increasingly interested in
the theoretical problems of the organization of knowledge and in the
development of standards for cataloguing and classification. Within a
period of about 40 years from the first publication of Melvil Dewey’s
Decimal Classification in 1876, all the general schemes of classification
that are widely used today, as well as the major system of subject
headings, came into being. Nowadays the majority of libraries use one of
the major schemes of classification (or a subject specialist scheme in the
case of special libraries) to organize the materials physically in the
collection: in other words, the classification is the means by which we
arrange books on shelves. The classification scheme may also be used to
organize the results of searches on the library catalogue, to arrange
printed bibliographies or lists of new books, or even to structure the
content of library intranets and online directories. Classification is a
fundamental tool in the process of organizing a collection and in the
complementary process of searching for and retrieving information.


Broughton Ess class 2e TEXT PROOF 05_Broughton prelims.qxd 04/06/2015 18:09 Page 7

3 First principles of
classification
Two ideas are fundamental to any system of classification: grouping and
ordering. Grouping is the primary act of classification and one that is
inherent in human thinking, as we saw in the introduction. We can all
classify in this sense quite instinctively.

Grouping

Exercise 3.1

Consider the following sets of concepts, and identify the odd one out in each.
1
2
3
4

banana
sausage
aubergine
cauliflower
spade
rake
trowel
frying pan
karate
kung-fu
knitting
kick-boxing
Paris
Rome
Idaho
Cairo

I hope your answers will be:
1
2
3
4

sausage (because the others are fruits and vegetables)
frying pan (because the others are garden implements)
knitting (because it is not a martial art)
Idaho (because it is not a capital city)

This may seem to be a trivial exercise, but it serves to illustrate the essence
of classification – the act of putting like with like and separating unlike – and
it shows that at the broad level it is quite easy to do. Hopefully you were able
not only to group the concepts, but also to identify the principles by which
you did this, so that there was a logical and philosophical basis to your
classification. The principle used to create a group is sometimes called the
principle of division or characteristic of division: this is the technical term
for the property or attribute that all the members of a group have in common.


Broughton Ess class 2e TEXT PROOF 05_Broughton prelims.qxd 04/06/2015 18:09 Page 8

8

ESSENTIAL CLASSIFICATION

Ordering

This process of grouping together related terms or concepts is central to
a classification scheme, and it forms the first stage in constructing a
classification. The second stage is to decide on the relationships between
groups, since this determines the order in which the groups will be
arranged.
Let’s start by making some groups within the general area of
vegetables. By putting like with like, we could organize the carrots,

parsnips and turnips to make a class of root vegetables. Now we need to
consider what will be placed next. We might want to position other
groups of vegetables (leafy vegetables, and pulses) near to the roots, and
then locate the whole class of vegetables near to other crops, such as
fruits and cereals. The next problem will be to decide what follows on
from the crops: will it be other plants that are not crops (such as wild
flowers or woodlands), or should it be animal ‘crops’ (pigs, cattle,
chickens), or perhaps the end products of the plant crops (bread,
processed vegetables, fruit drinks)?
There is obviously more than one potential answer here, and it’s
impossible to say that there is a correct order, or that one arrangement is
better than another in any absolute sense. The difficulty arises because
we’re trying to put all of these subjects (and potentially the whole of
knowledge) into a straight line: the single sequence, or linear order, can’t
take account of the variety of relationships that exist between subjects.
This problem isn’t limited to arranging books on shelves: it also occurs in
other situations where goods need to be displayed – shops are an obvious
example. The parallels between the library collection and the supermarket
are numerous and we shall return to this useful analogy later.
The fact of this complexity of relationships, and how they are sorted out
in practice, will determine how effective a classification is for a particular
subject, or in a particular context: our example of plants, animals, crops
and products would have different optimum orders for a biologist, a
farmer, a food technologist or an economist, and this variability is
multiplied a thousandfold across the whole of knowledge. This gives us
the first fundamental law of classification – there are lots of possible right
ways to do things. There is usually not a single ‘correct’ order of subjects,
but only an appropriate or helpful order, which changes according to the
situation, and the needs and interests of the users.
Some general theoretical principles of ordering are used in classific-

Broughton Ess class 2e TEXT PROOF 05_Broughton prelims.qxd 04/06/2015 18:09 Page 9

FIRST PRINCIPLES OF CLASSIFICATION

9

ation schemes: chronological order is an obvious one, and proximity is
used as the basis of ordering geographical places. Developmental orders
and orders based on complexity can be used in classifying the natural
world, and the idea of dependency is also often employed: for example,
life forms are dependent on their chemical constituents and therefore
biochemistry must precede botany and zoology. Nevertheless, much
ordering in classifications is done on a pragmatic and arbitrary basis.
Who can say whether motorways should precede or follow metal fatigue,
or how ice-skating is related to infinitesimal calculus?

Compound subjects

Let’s go back to the odd-one-out game.
Exercise 3.2

Consider the following groups of terms and identify the misfit in each:
1
2
3
4

Brahms

Schumann
Bizet
Goethe
hamster
chicken
sheep
pig
chimney
window frame
door
table
whooping cough
chickenpox
asthma
tuberculosis

Now we begin to see the ‘no-right-answer’ syndrome in action. Is the
answer to number 1 Bizet (the Frenchman among Germans) or Goethe
(the poet among musicians)? Number 2 could be the chicken (the odd
bird out) or the hamster (which isn’t on the menu for Sunday lunch),
and number 3 might be the table (which isn’t part of a house) or the
chimney (which is unlikely to be made of wood). Number 4 is slightly
trickier to sort out but here are either three infectious diseases and one
with environmental causes (asthma), or three diseases of the respiratory
system and a more general systemic condition, chickenpox.
What is happening here is a demonstration of the fact that concepts
usually have more than one characteristic or attribute. While in the first
game the principles for grouping were clear, in this case two properties
have equal claim as the basis for arrangement.
If we consider the problems of storage and retrieval at the

supermarket we see that the same difficulty occurs. If I want to buy some
frozen peas I need to know whether they will be found with other types
of peas (fresh, tinned and dried), or with other frozen goods (sweetcorn,


Broughton Ess class 2e TEXT PROOF 05_Broughton prelims.qxd 04/06/2015 18:09 Page 10

10

ESSENTIAL CLASSIFICATION

beans and broccoli). From the customer’s point of view it doesn’t matter
very much which way round the shop does this as long as it’s clear what
the arrangement is. If the organization is predictable then I can retrieve
what I want efficiently, since I can go straight to the correct location.
The same is true of documents: if I want a book on deficiency diseases
of the bones, I need to know whether all books on deficiency diseases are
kept together (divided by parts of the body affected) or whether books
on specific parts of the body are grouped (divided by types of disease).
Then I can make an informed decision about where the documents I
want will be located. Subjects of this kind, with more than one aspect or
component, are called compound subjects.
The question of where to put the frozen peas may have only two
possible answers, but the subjects of books can be a great deal more
complicated. When Dewey first published his Decimal Classification, in
1876, the subjects of books were usually less complex than they are
today. Although there will always be books with subjects such as
mathematics or cookery or cricket, the majority of modern publications
are much more complicated. Consider the following:
Example

Nineteenth-century French poetry / Michael Bishop . — New
York : Twayne, 1993

The subject in this example clearly has three parts: language (French),
form (poetry) and period (19th century). Imagine that your library has
been given a large collection of literature books of this type, all having
subjects which contain a language, a literary form and a period. Some
typical titles might be ‘Twentieth-century Russian fiction’, ‘Mediaeval
French poetry’, ‘Swedish drama in the 19th century’, ‘Plays of the Italian
cinquecento’ and ‘The novel in 17th-century England’. Your task is to
sort them out.
Perhaps you’re in a library in a college where foreign literature is taught
alongside foreign languages, and it occurs to you that the most useful
arrangement of the books would be to group them into sets dealing with
each separate language: a French collection, a Swedish collection, an
Italian collection and so on. You could of course sort them into groups of
the different periods, or into different literary forms, but let’s go with the
first option.


Broughton Ess class 2e TEXT PROOF 05_Broughton prelims.qxd 04/06/2015 18:09 Page 11

FIRST PRINCIPLES OF CLASSIFICATION

11

After you’ve done this you should have several heaps of books, each of
which contains only books about a particular language. Select one of
these heaps – let’s say the Italian books. There’s still a degree of disorder

here because some of them are about 16th-century Italian poetry, and
some are about mediaeval Italian drama, or 20th-century Italian novels,
and so on. Now you can do one of two things – you can sort the Italian
books into piles of each different period, or you can sort them into piles
of the different forms of literature. Let’s take the second option this
time, and create some sets of Italian poetry, Italian novels, Italian essays,
etc., etc. The only thing left to do now is to take each of these groups and
divide them up by period, so that Italian poetry is sorted into mediaeval
Italian poetry, 16th-century Italian poetry, 17th-century Italian poetry
and so on.
Now turn to the other heaps of languages and repeat the process: it
would be sensible to sort these out on the same basis as the Italian books,
sorting first into groups of the different literary forms, and then
subdividing these by period. Finally you can arrange all the books on
shelves, keeping your separate sections together in their logical order.
At this point if a library user comes along and asks you how the
collection is organized you can say that everything is arranged firstly by
language and then by form and then finally by period. You have used three
principles of division – language, form and period – and you have
applied the principles of division in the order: 1. Language; 2. Form; 3.
Period. This order is called the citation order for the classification of
literature books you’ve created.

Citation order

Whether it has been logically arrived at or not, some sort of citation order
exists in any collection of compound subjects. In supermarkets the
citation order is ‘form of preservation’ followed by ‘type of food’, as shown
in Figure 3.1. When we apply a citation order we’re bringing the two
F

R
E
S
H

Beans
Peas
Sweetcorn
Carrots

T
I
N
N
E
D

Beans
Peas
Sweetcorn
Carrots

Figure 3.1 Supermarket citation order

F
R
O
Z
E
N

Beans
Peas
Sweetcorn
Carrots


Broughton Ess class 2e TEXT PROOF 05_Broughton prelims.qxd 04/06/2015 18:09 Page 12

12

ESSENTIAL CLASSIFICATION

classificatory principles of grouping and ordering together, in order to
create a logical and predictable sequence. Citation order is consequently a
very important principle in classification, and we shall be returning to it
frequently.
An inescapable outcome of bringing together objects on the basis of
one attribute is that other attributes are scattered. At the shop, all the
frozen foods are kept together, but the carrots are in different places
according to whether they are in tins, freezer bags or loose; these
different sets of carrots are known as distributed relatives. When we
have to produce a linear order, as on the library (or supermarket) shelf,
or in a screen display or a printed list, this scattering is inevitable, and
we must decide which aspects of things are more important for
grouping, and which are secondary and can be distributed. The citation
order can be varied for different groups of users, although only one
citation order should be used in a particular collection: if citation orders
are muddled searchers won’t be able to predict locations, and retrieval
will be much more difficult to achieve.

Summary

•
•
•
•
•
•

The first act in classification is that of grouping objects or concepts.
Grouping brings together like concepts, according to their properties or
attributes.
Ordering is the next process, to determine the sequence of groups.
Problems occur when objects have more than one attribute and we have to
decide which is most important for grouping.
The order of importance of attributes is called citation order.
Properties which are scattered by the citation order are called distributed
relatives.


Broughton Ess class 2e TEXT PROOF 05_Broughton prelims.qxd 04/06/2015 18:09 Page 13

4 The variety of classification:
systems and structures
So far we’ve looked at fairly informal examples of sorting and
arrangement – what might be done on a pragmatic basis and at a local
level. One wouldn’t expect the supermarket classification, or a rough
arrangement of literature books, to be written down or distributed for
others to use. The world is full of examples of this sort of local or
personal classification; office filing systems are a typical example, as is

any arrangement of the content of your kitchen cupboards or your
wardrobe.
At a more public level there are a vast number of formal, published
classifications of an immense variety of entities and phenomena. A search
for ‘classification of ’ using Google will return you in excess of 360 million
sites. Among these are classifications for proteins, reptiles, disabilities,
wetlands, daffodils, scorpions, depression, learning skills, theories of
divine action, caviar, parachutes, subtle changes in facial expression,
portable fire extinguishers, Bible commands, angles, thunderstorms,
millionaires, chickens and tea.

Scientific classifications and taxonomies

For the most part these are classifications of different sorts of physical
and biological entities, and they’re constructed using the fundamental
principles of grouping and ordering, which we discussed in Chapter 3,
in a more extended, rigorous and systematic manner. The
methodology they employ goes back to the Greek philosopher
Aristotle, who, in the Organon, laid down the rules for creating
categories of objects in the natural world. Aristotle produced the first
classification for natural history, and the methods he used endure to
the present day. He grouped natural phenomena (plants, birds,
animals, people) into sets based on attributes or properties relating to
their external appearance and behaviour, and he ordered these groups
on the basis of their comparative similarity (or dissimilarity).


Broughton Ess class 2e TEXT PROOF 05_Broughton prelims.qxd 04/06/2015 18:09 Page 14

14

ESSENTIAL CLASSIFICATION

A classification of this kind is referred to as a taxonomy (from the
Greek taxis meaning arrangement or order, and nomos, meaning law or
rule). Although information managers often use the term taxonomy
today to mean any vaguely structured set of terms in a subject area,
taxonomy is a major scientific discipline with a highly developed, exact
and complex methodology, usually supported by computational
techniques.
Aristotle’s methods were taken up by scientists of the Renaissance
and the Enlightenment, such as the Swedish naturalist Linnaeus. He
used the same techniques to produce a classification of living things that
is still, with some modifications, widely used today. Linnaeus’s
classification is based on the anatomical structure or morphology of
living things, and it contains some odd associations: hydrangeas and
gooseberries are in the same family, and elm trees and stinging nettles
are also close relations. Nevertheless, the principles underlying the
classification are clear and its long persistence demonstrates its value.
Linnaeus’s classification is typical of a taxonomy in that the
relationships between living things are depicted by means of a
hierarchical structure. This is a structure in which successive steps in
division create smaller and more specific classes. It is usually
represented visually as a tree structure (Figure 4.1), with the tree
Living things
Plants

Animals
Vertebrates

Mammals

Invertebrates

Birds

Passerines

Micro-organisms

Reptiles
Rollers

Bee-eaters

Hoopoes
Upupa epops

Figure 4.1 Classificatory tree structure

Amphibians
Ducks

Herons

Kingfishers

Fish