Knowl. Org. 35(2008)No.2/No.3
B. Hjørland. What is Knowledge Organization (KO)?
86
What is Knowledge Organization (KO)?
Birger Hjørland
Royal School of Library and Information Science,
6 Birketinget,DK-2300 Copenhagen S, Denmark,
<bh@db.dk>
Birger Hjørland, MA in psychology and PhD in Library and Information Science. Professor in
Knowledge Organization (KO) at the Royal School of Library and Information Science in Copenhagen
since 2001. Professor in KO at the University College in Borås, Sweden 2000-2001. Research
librarian and coordinator of computer based information services at the Royal Library in Copenhagen
1978-1990. Taught information science at the Department of Mathematical and Applied Linguistics
at the University of Copenhagen 1983-1986. 1974-1978 associate professor at RSLIS, and 1990-
2000 head of department. He has published several papers on KO, including about 11 papers in the
journal Knowledge Organization and the book Information Seeking and Subject Representation: An
Activity-Theoretical Approach to Information Science (Greenwood Press 1997).
Hjørland, Birger. What is Knowledge Organization (KO)? Knowledge Organization, 35(3/2), 86-101. 45 references.
ABSTRACT: Knowledge Organization (KO) is about activities such as document description, indexing and classification performed
in libraries, databases, archives etc. These activities are done by librarians, archivists, subject specialists as well as by
computer algorithms. KO as a field of study is concerned with the nature and quality of such knowledge organizing processes
(KOP) as well as the knowledge organizing systems (KOS) used to organize documents, document representations and concepts.
There exist different historical and theoretical approaches to and theories about KO, which are related to different views
of knowledge, cognition, language, and social organization. Each of these approaches tends to answer the question: “What is
knowledge organization?” differently. LIS professionals have often concentrated on applying new technology and standards,
and may not have seen their work as involving interpretation and analysis of meaning. That is why library classification has
been criticized for a lack of substantive intellectual content. Traditional human-based activities are increasingly challenged by
computer-based retrieval techniques. It is appropriate to investigate the relative contributions of different approaches; the current
challenges make it imperative to reconsider this understanding. This paper offers an understanding of KO based on an
explicit theory of knowledge.
1. Introduction: knowledge organization—
the narrow and the broader meaning of
the term
In the narrow meaning Knowledge Organization
(KO) is about activities such as document description,
indexing and classification performed in libraries,
bibliographical databases, archives and other
kinds of “memory institutions” by librarians, archivists,
information specialists, subject specialists, as
well as by computer algorithms and laymen. KO as a
field of study is concerned with the nature and quality
of such knowledge organizing processes (KOP)
as well as the knowledge organizing systems (KOS)
used to organize documents, document representations,
works and concepts. Library and Information
Science (LIS) is the central discipline of KO in this
narrow sense (although seriously challenged by,
among other fields, computer science).
In the broader meaning KO is about the social division
of mental labor, i.e. the organization of universities
and other institutions for research and higher
education, the structure of disciplines and professions,
the social organization of media, the production
and dissemination of “knowledge” etc. A book
such as Oleson & Voss (1979) The Organization of
knowledge in modern America, 1860-1920 is an example
of the study of knowledge organization in the
broad sense. We may distinguish between the social
organization of knowledge on one hand, and on the
other hand the intellectual or cognitive organization
of knowledge. The broad sense is thus both about
Knowl. Org. 35(2008)No.2/No.3
B. Hjørland. What is Knowledge Organization (KO)?
87
how knowledge is socially organized and how reality
is organized. The uncovering of structures of reality
is done by the single sciences, e.g. chemistry, biology,
geography and linguistics. Well known examples are
the periodic system in chemistry and biological taxonomy.
Generalized theories about the structure of
reality, such as the theory of integrative levels first advanced
by Auguste Comte belong to the philosophical
disciplines “metaphysics” and “ontology.”
While Library and Information Science (LIS) is the
central discipline concerned with KO in the narrow
sense of the word, other disciplines such as the sociology
of knowledge, the single sciences and metaphysics
are central disciplines concerned with KO in
the broader sense of the word. The importance of regarding
the broader field of KO is related to the question
about how KO in the narrow sense can be developed.
A central claim of this paper is that KO in the
narrow sense cannot develop a fruitful body of
knowledge without considering KO in the broader
perspective. In other words: There exists no closed
“universe of knowledge” that can be studied by KO
in isolation from all the other sciences’ study of real-
ity.
Further description of the field of KO is dependent
on the theoretical perspective, which is why we
shall introduce the most important perspectives be-
low.
2. Theoretical approaches to knowledge
organization
KO has mainly been a practical activity without
much theory. Miksa (1998, 49), for example, wrote:
Now, we could simply conclude with Dolby
and others that library classification continues
mainly as a practical matter, that it is by and
large devoid of substantive intellectual content,
and that it continues merely because of inertia
in a field in which classification schemes invented
late in the nineteenth century continue
to be used.
It has often been assumed that the practical organization
of knowledge can be done by applying common
sense or, in major research libraries and bibliographical
databases, by employing subject specialists,
who just apply their special knowledge. LIS professionals
have often concentrated on applying new
technology, software and standards. They have often
seen themselves as applying standards for description
of a relative objective nature. In other words
practical KO may have been seen as a syntactic,
rather than as a semantic activity as differentiated by
Julian Warner (2007):
Semantic labor is concerned with transformations
motivated by the meaning or signified of
symbols, while syntactic labor is determined by
the form alone of symbols, operating on them
in their aspect as signals. Semantic labor requires
direct human involvement while originally
human syntactic labor can be transferred
to information technology, where it becomes a
machine process.
Since the 1950s, computer scientists have been working
with KO based on certain assumptions, mostly
assuming that human classification and indexing will
soon be made superfluous. A recent example (Sparck
Jones 2005) is that automated systems based on relevance
feedback from users might solve problems efficiently.
Genuine theoretical contributions to KO
are very rare, but seem mandatory in relation to the
challenges with which this field is confronted. More
and more people discuss the doomsday scenario for
library and information science (cf., Bawden 2007).
There exist many separated communities working
with different technologies, but very little research
about their basic assumptions and relative merits and
weak sides. The problem is not just to formulate a
theory, but to uncover theoretical assumptions in
different practices, to formulate these assumptions
as clearly as possible in order to make it possible to
compare approaches.
A further problem is that the adherents of different
approaches try to avoid criticism by incorporating
ideas from competing approaches. The field cannot
advance, however, without theoretical clarity, which is
why it is important to describe different approaches
in a way that they can be distinguished from each
other and compared with each other. In other words:
we have to examine and interpret different labels used
for approaches very honestly and carefully. Otherwise
we will stay in a very muddled field.
One way to classify approaches to KO was suggested
by Broughton, Hansson, Hjørland and
López-Huertas (2005):
1. The traditional approach to KO expressed by classification
systems used in libraries and databases,
including DDC, LCC and UDC (going back to
about 1876).
Knowl. Org. 35(2008)No.2/No.3
B. Hjørland. What is Knowledge Organization (KO)?
88
2. The facet-analytical approach founded by Ranganathan
about 1933 and further developed by the
British Classification Research Group.
3. The information retrieval tradition (IR) founded
in the 1950s.
4. User oriented and cognitive views gaining influence
from the 1970s.
5. Bibliometric approaches following Garfield’s construction
of the Science Citation Index in 1963.
6. The domain analytic approach (first formulated
about 1994).
7. Other approaches (among recent suggestions are
semiotic approaches, “critical-hermeneutical” approaches
discourse-analytic approaches and genrebased
approaches. An important trend is also an
emphasis on document representations, document
typology and description, mark up languages,
document architectures etc.).
Each of the 6 approaches (but not other approaches)
will be presented and discussed below.
2.1 The traditional approach
It is difficult to define “the traditional approach” because
there is no united theory that corresponds to
this concept. If we disregard the other approaches to
be introduced, what exist are mostly various different
practices and some scattered suggestions on how to
organize knowledge. Even a single system such as the
Dewey Decimal Classification (DDC) has used quite
different principles in various editions (cf., Miksa
1998). The classification researcher Vanda Broughton
(2004, 143) wrote about one of the old established
systems: “It is quite hard to discern any strong theoretical
principles underlying LCC [Library of Congress
Classification].” Also some formulations by S. R.
Ranganathan (e.g., 1951) suggest that “traditional”
systems seem to lack a theoretical foundation (in his
eyes as opposed to his own approach).
Among the major figures in the history of KO,
which can be classified as “traditional,” are Melvil
Dewey (1851-1931) and Henry Bliss (1870-1955).
Eugene Garfield wrote about Bliss (1975, 252): “His
goals and aspirations were different from those of
Melvil Dewey, whom he certainly surpassed in intellectual
ability, but by whom he was dwarfed in organizational
ability and drive. Dewey was a businessman,
but he was in no sense as profound in his
accomplishments.” This difference in the character
of the two men is reflected in their approach to
knowledge organization as also reflected by Miksa’s
(1998, 42-45) presentation of Melvil Dewey’s business
perspective. Dewey’s business approach is
hardly an intellectual approach on which the field
can find a theoretical foundation for KO understood
as an academic discipline. His interest was not to
find an optimal system to support users of libraries,
but rather to find an efficient way to manage library
collections. He was interested in developing a system
which could be used in many libraries, a standardized
way to manage library collections.
DDC should thus be seen as the dream of the library
administrator rather than the dream of the library
user. It is not designed for any specific collection
and must be seen as a compromise between different
collections and corresponding scholarly interests.
In order to minimize the workload in libraries,
the system is conservative in the sense that it often
prefers to avoid structural change. In other words,
internal consistency over different editions has often
taken priority compared to updating the system in
order to make it more in accordance with the surrounding
society. The user does not get a detailed,
realistic view about relations between disciplines and
fields of knowledge, but the library administrator
gets a system in which most of the books are already
classified by other libraries or agencies and which is
used for both shelf arrangement and catalog searching.
The library administrator may hire people from
library schools, who know the system and may apply
this knowledge in all the libraries using DDC. The
system is thus also supporting professional interests.
It probably represents a rationalization of library
work more than anything else. Its main quality may
be that it represents a standard and not a system optimized
for browsing or retrieval for any particular
interest. It should be added that what is today called
Library and Information Science, LIS, was termed library
economy in 1876 when the system was first
published, which is also an indication of the administrative
rather than the academic goals of the system.
This may also explain why systems designed on the
basis of more modern principles have not succeeded
in influencing practice in libraries.
Among the critics of the DDC is Bernd Frohmann,
who wrote (1994, 112-13):
Dewey's subjects were elements of a semiological
system of standardized, techno-bureaucratic
administrative software for the library in its
corporate, rather than high culture, incarnation….
Dewey emphasized more than once
that his system maps no structure beyond its
Knowl. Org. 35(2008)No.2/No.3
B. Hjørland. What is Knowledge Organization (KO)?
89
own; there is neither a “transcendental deduction”
of its categories nor any reference to Cutter's
objective structure of social consensus. It
is content-free: Dewey disdained any philosophical
excogitation of the meaning of his class
symbols, leaving the job of finding verbal
equivalents to others. His innovation and the
essence of the system lay in the notation. The
DDC is a poorly semiotic system of expanding
nests of ten digits, lacking any referent beyond
itself.… The conflict of interpretations over
“subjects” became explicit in the battles between
“bibliography” (an approach to subjects
having much in common with Cutter's) and
Dewey's “close classification.” William Fletcher
spoke for the scholarly bibliographer....
Fletcher's “subjects,” like Cutter's, referred to
the categories of a fantasized, stable social order,
whereas Dewey's subjects were elements of
a semiological system of standardized, technobureaucratic
administrative software for the library
in its corporate, rather than high culture,
incarnation.
The quote from Frohmann shows that already when
Melvil Dewey published his system there was a critique
of the DDC as being empty and rather nonacademic.
Dewey’s attitude may have influenced library
philosophy and practice. LIS professionals may
have seen their work more like a syntactical activity
that an activity involving interpretation and analysis
of meaning.
In order to identify an approach to KO which
may deserve the label “the traditional approach,” we
shall turn to other scholars, including Henry Bliss.
An important characteristic in his (and many contemporary
thinkers of KO) was that the sciences
tend to reflect the order of Nature and that library
classification should reflect the order of knowledge
as uncovered by science:
Natural order → Scientific Classification →
Library classification (KO)
The implication is that librarians, in order to classify
books, should know about scientific developments.
This should also be reflected in their education
(Ernest Cushing Richardson, quoted from Bliss
1935, 2):
Again from the standpoint of the higher education
of librarians, the teaching of systems of
classification ... would be perhaps better conducted
by including courses in the systematic
encyclopedia and methodology of all the sciences,
that is to say, outlines which try to
summarize the most recent results in the relation
to one another in which they are now
studied together.
This important principle has been implicit in the
management of research libraries and bibliographic
databases such as MEDLINE, in which subjects specialists
are often hired to do the work in KO. The
importance of subject knowledge has not been explicit
in the following approaches to KO except in
domain analysis (and outside LIS in certain computer
approaches).
Among the other principles which may be attributed
to the traditional approach to KO are:
– Principle of controlled vocabulary
– Cutter’s rule about specificity
– Hulme’s principle of literary warrant (1911)
– Principle of organizing from the general to the
specific.
The principle of controlled vocabulary is essentially a
way of avoiding synonyms and homonyms as indexing
terms by using standardized vocabulary. Cutter’s
rule states that it is always the most specific, most
appropriate expressions that should be looked up in
the vocabulary of notations and assigned to documents.
In this way the expressions for the topics to
be made retrievable are rendered most predictable.
The term “literary warrant” as well as the basic principle
underlying this expression was introduced by
E. Wyndham Hulme (1911, 447). Hulme discusses
whether, for example, the periodic system of chemistry
should be used for book classification. He writes
(1911, 46-47):
In Inorganic Chemistry what has philosophy to
offer? [Philosophy here meaning science,
which produced the periodic system]. Merely a
classification by the names of the elements for
which practically no literature in book form exists.
No monograph, for instance, has yet been
published on the Chemistry of Iron or Gold….
Hence we must turn to our second alternative
which bases definition upon a purely literary
warrant. According to this principle definition
is merely the result of an accurate survey and
measurement of classes in literature. A class
Knowl. Org. 35(2008)No.2/No.3
B. Hjørland. What is Knowledge Organization (KO)?
90
heading is warranted only when a literature in
book form has been shown to exist, and the
test of the validity of a heading is the degree of
accuracy with which it describes the area of
subject matter common to the class. Definition
[of classes or subject headings], therefore, may
be described as the plotting of areas preexisting
in literature. To this literary warrant a
quantitative value can be assigned so soon as
the bibliography of a subject has been definitely
compiled. The real classifier of literature
is the book-wright, the so-called book classifier
is merely the recorder.
The principle of ordering from general subjects to
specific subjects is generally acknowledged and may
be related to an essentialist way of understanding.
Today, after more than 100 years of research and
development in LIS, the “traditional” approach still
has a strong position in KO and in many ways its
principles still dominate. The traditional approach,
however, shows signs of a certain vagueness in its
theoretical and methodological basis. Is it subject
knowledge rather than competency in KO that marks
the construction and administration of knowledge
organizing systems? Often it seems to be assumed
that that the organization of knowledge is just a matter
of “reading” the correct relations between concepts.
There is not much indication of how this is
done. Although debates about the philosophy of science,
e.g. in relation to positivism, was not unknown
among the founding fathers of knowledge organization,
they were not particularly clear on this point
and the same is also the case with the ordinary practice
of KO. It is with the development of the domainanalytic
approach that the question about the subjectivity
and objectivity of KO in a systematic way is
first built into the methodological foundation of KO.
2.2 The facet-analytical approach
The date of the foundation of this approach may be
chosen, for example, as the publication of S. R. Ranganathan’s
Colon Classification in 1933. The approach
has been further developed by, in particular,
the British Classification Research Group. In many
ways this approach has dominated what might be
termed “modern classification theory.” The BC2 system
is probably today the theoretically most advanced
system based on this theory (and has also
contributed to the further development of this ap-
proach).
The best way to explain this approach is probably
to explain its analytico-synthetic methodology. The
meaning of the term “analysis” is: breaking down
each subject into its basic concepts. The meaning of
the term synthesis is: combining the relevant units
and concepts to describe the subject matter of the
information package in hand. Given subjects (as they
appear in, for example, book titles) are first analyzed
into a few common categories, which are termed
“facets.” Ranganathan proposed his PMEST formula:
Personality, Matter, Energy, Space and Time:
– Personality is the distinguishing characteristic of a
subject
– Matter is the physical material of which a subject
may be composed
– Energy is any action that occurs with respect to
the subject
– Space is the geographic component of the location
of a subject.
– Time is the period associated with a subject.
The British Classification Research Group (CRG)
expanded this list, but here we shall only consider the
original one. The first assumption is that all subjects
can be analyzed in a way that fits into these five categories.
Those categories have been developed before
the books have been written and arrived in the library.
In other words, they are neither dynamically developed
nor empirically given: they are logical, a priori
categories. Each category (facet) has in principle its
own classification or lists of symbols. A given document
is classified by taking one or more symbols
from the appropriate facets and combining them according
to certain rules. This combination is called
notational synthesis. The idea is that the same building
blocks can be used for all purposes. The underlying
philosophical assumption is that elements do not
change their meaning in different contexts. This assumption
has never, as far as I know, been discussed
in the literature. According to modern theories of
meaning it is a rather problematic assumption.
Ranganathan has had many followers in LIS. It has
however, been extremely difficult to trace critical examinations
of this approach. Very few researchers have
had the broader knowledge which enabled them to
consider this approach in relation to fields like philosophy
and linguistics. Among the few who have
done this is Moss (1964) who found that Ranganathan
based his system of five categories on that of Aristotle
without recognizing this. Another critical voice is
Francis Miksa, who, for example, wrote (1998, 73):
Knowl. Org. 35(2008)No.2/No.3
B. Hjørland. What is Knowledge Organization (KO)?
91
In the end, there is strong indication that Ranganathan's
use of faceted structure of subjects
may well have represented his need to find
more order and regularity, in the realm of subjects,
than actually exist.… Ranganathan vigorously
pursued the goal of finding one best subject
classification system.
Hjørland (2007b, 382-84) related the basic philosophy
of facet analysis to the philosophy of semantic
primitives and thus to a broader theory of semantics.
According to his analysis, semantic elements are not
direct attributes of language, but are related to models
of reality, which are then expressed in language.
Chemical compounds may, for example, be expressed
in chemical formulae by chemical elements. Chemical
elements are discovered and named by chemists; they
are not given elements in natural languages. The
names of the chemical elements are in this case the
semantic primitives. Semantic relations, including the
relation between elements and composed expressions,
are thus connected to theories of reality.
S. R. Ranganathan wrote in his ‘Philosophy of Library
Classification’ (1951, 87ff.):
An enumerative scheme with a superficial
foundation can be suitable and even economical
for a closed system of knowledge.... What distinguishes
the universe of current knowledge is
that it is a dynamical continuum. It is ever
growing; new branches may stem from any of
its infinity of points at any time; they are unknowable
at present. They can not [sic] therefore
be enumerated here and now; nor can they
be anticipated, their filiations can be determined
only after they appear.
Ranganathan thus expresses the views:
1. That enumerative systems have a superficial
foundation;
2. That the discovery of new knowledge cannot
be anticipated in an enumerative system;
and,
3. That the discovery of new knowledge can be
anticipated in a faceted system (based on the
view that new knowledge is formed by combination
of a priori existing categories).
These views reveal some basic assumptions in the
facet-analytic approach. The difference between the
theoretical foundations of enumerative systems
compared to faceted systems is not that the former
have a superficial foundation while the latter have a
profound foundation. The basic questions in knowledge
organization are shared by both approaches:
How terms are selected and defined and their semantic
relations established. This is not a purely logical
matter, but largely an empirical question. While it is
correct that it may be easier to combine existing
elements to form new classes and thus easier to place
new subjects in faceted systems, it is of course impossible
for any system to anticipate the discovery of
new knowledge. The belief that this should be possible
reveals that part of the philosophy of facet analysis
is without contact with the real world.
La Barre (2006) found that faceted techniques are
increasingly being used in the design of web-pages.
A specific format, XFML, a simple XML format for
exchanging metadata in the form of faceted hierarchies
has been developed (Van Dijck 2003). The
technique is thus very alive and in use.
2.3 The information retrieval tradition (IR)
Information retrieval (IR) and knowledge organization
(KO) are normally considered two different—
although strongly related—subfields within Library
and Information Science (LIS)—related respectively
to search labor and description labor (Warner 2002).
They are, however, trying to solve the same kind of
problems: enabling users to find relevant information.
For this reason we have to consider them competing
approaches, and thus try to evaluate their
relative strengths and weaknesses. The question then
becomes: how can IR be characterized as an approach
relative to the other approaches discussed?
One way to do this has been to make a distinction
between the “physical paradigm” (or “system-driven
paradigm”) on one side and “user-oriented” or “cognitive
paradigm” on the other. The IR tradition has
been understood as “systems driven” as if the system
makes a decision of what to present for the users
(Gruzd 2007, 758).
In the conventional system-oriented view, a
“perfect” system is defined as one that finds the
best match between a user’s stated request and
documents from a collection. This view has
proven to be very limiting. It has led many researchers
to focus only on how to improve
various aspects of document representations
and the matching algorithms. As a result, the
system-oriented approach to IR tends to disre-
Knowl. Org. 35(2008)No.2/No.3
B. Hjørland. What is Knowledge Organization (KO)?
92
gard users’ cognitive behaviors as well as the
problem-solving context in which an IR process
is being carried out. It has become evident
that to succeed, IR researchers need to look
beyond machine algorithms.
This distinction between “the system-oriented view”
and “the user-oriented view” may, however, represent
a misinterpretation. The difference between the
Cranfield experiments and user-oriented views is first
and foremost that the Cranfield experiments are
based on expert evaluations of recall and precision,
while the user-oriented views are based on users’
evaluation. It is never the technology that makes the
decision of what is relevant. The technology is just
constructed on the basis of some views of what is
relevant and how this can be measured. Neither the
system-oriented view nor the user-oriented view has
considered the epistemological problem: How are answers
to queries related to different theories or
views?
Important in the IR tradition have been, among
others, the Cranfield experiments, which were
founded in the 1950s, and the TREC experiments
(Text Retrieval Conferences) starting in 1992. It was
the Cranfield experiments which introduced the famous
measures “recall” and “precision” as evaluation
criteria for systems efficiency. The Cranfield experiments
found that classification systems like UDC
and facet-analytic systems were less efficient compared
to free-text searches or low level indexing systems
(“UNITERM”). The Cranfield I test found according
to Ellis (1996, 3-6) the following results:
UNITERM 82.0% recall
Alphabetical subject headings 81.5% recall
UDC 75.6% recall
Facet classification scheme 73.8% recall.
Although these results have been criticized and questioned,
the IR tradition became much more influential
while library classification research lost influence.
The dominant trend has been to regard only
statistical averages. What has largely been neglected
is to ask: Are there certain kinds of questions in relation
to which other kinds of representation, for example,
controlled vocabularies, may improve recall
and precision?
Julian Warner (2002) has characterized the dominant
IR tradition with the word “query transformation”
meaning that systems automatically transform
a query to a set of relevant references. He contrasts
this principle by what he terms ”selection power,” a
principle that, according to him has been valued in
traditional library work.
Although thesauri were developed in the IR
tradition, this is the exception that confirms the rule:
The IR approach may be characterized as generally
sceptical of all forms of human interpretation, indexing
and classification. Its focus has clearly been on
free-text retrieval: the assumption that texts contain
all necessary information needed to retrieve them.
Recently Karen Sparck Jones (2005) wrote that traditional
(pre-)classification probably is obsolete and
may be replaced by new promising techniques such
as relevance feedback. If Sparck Jones’ view is typical
of the IR approach, then a criticism of this view may
provide the basis of an alternative to the IR
approach. In fact, two basic criticisms of relevance
feedback can be summarized:
1. Relevance feedback is based on certain premises
about users’ knowledge that are largely unexplored
and may turn out to be highly unrealistic:
If users do not have the necessary knowledge to
classify a domain, they cannot distinguish relevant
and non-relevant documents and are thus unable
to provide useful feedback.
2. Relevance feedback represents unspecified and
unclear semantic relations between documents
considered relevant. Why prefer a kind of system
implying unspecified relations rather than specified
and user-controlled relations?
In conclusion: The IR tradition has generally been
based on positivist assumptions: that optimal retrieval
can be determined by retrieval tests without
considering different views or “paradigms” and without
considering text corpora as a merging of different
views each putting different meanings to terms. In
other words, it has mainly been based on statistical
averages, and has neglected to investigate how different
kinds of representation and algorithms may serve
different views and interests.
2.4 User-oriented views
In some sense, all approaches to KO may agree about
the goal that systems and processes are aimed at fulfilling
users’ “information needs.” For example, facet
analytic researchers may rightly claim that users
benefit from well structured systems, which is why
this approach is “user-oriented” or “user friendly.” If
the term “user-oriented” is to be a meaningful label
Knowl. Org. 35(2008)No.2/No.3
B. Hjørland. What is Knowledge Organization (KO)?
93
for an approach, it needs to be defined in a more precise
way. We need to distinguish at least the following
meanings:
– User-friendly knowledge organization
– Market-oriented knowledge organization
– Knowledge organization based on empirical studies
of users
– Knowledge organization done by users (e.g. the
recent trend in folksonomies).
The best way to define this approach is probably by
method: Systems based upon user-oriented approaches
must specify how the design of a system is
made on the basis of empirical studies of users.
User studies demonstrated very early that users
prefer verbal search systems as opposed to systems
based on classification notations. This is one example
of a principle derived from empirical studies of
users. Adherents of classification notations may, of
course, still have an argument: That notations are
well-defined and that users may miss important information
by not considering them.
In order to consider the function of empirical user
studies it might be fruitful to consider the development
of a field such as biological systematics. Table 1
shows Mishler’s (2000) historical outline of this
domain:
Historical periods in biological systematics
(after Mishler, 2000)
1) Pre-history. Folk classifications
* 2) Ancient Greeks through Linneaeus: Essentialism
* 3) Natural system. Overall resemblance; “impor-
tance.”
4) Darwin. Evolutionary language added (Only a superficial
effect for a long time, cf. 6)
5) Numerical Phenetics. Computers added. (Only a
superficial effect)
* 6) Phylogenetic systematics (Cladistics). [A late
Darwinian approach]
[*7) Systematics based on DNA-analysis]
* argued by Mishler (2000) to be the only true
revolutions in the conceptual bases of systematics
Table 1. Mishler’s (2000) outline of the domain
of biological systematics
The table shows how “folk classification” was succeeded
by an essentialist classification from Aristotle
to Linné, then by a natural classification [founded by
de Jussieu] and later by phylogenetic systematics and
DNA-analysis. Thus, according to this outline folk
classification represented a pre-scientific period. One
might ask: Are classifications based on empirical information
from users to enjoy the same status as folk
classifications (i.e., to represent a pre-scientific form
of knowledge organization)? Do adherents of useroriented
views find that it is better to base classification
systems for libraries and bibliographical databases
on folk classifications and user studies rather
than on scientific methods?
It is strange that somebody seems to believe so.
Are amateurs supposed to know better? In some
cases, of course, it may be hard to find experts among
established researchers. In the case of music, established
researchers have not until recently regarded
popular music and experts have had to be found in
other circles, for example, among journalists and the
users themselves. Even in that case, it is probably not
the average user who knows about relevant genre
concepts, but some experts among the users. That being
said, it must be admitted that some serious researchers
do regard biological folk-classification equal
to scientific classification (Dupre 2006).
Hjørland (2007a) found that user-oriented views
seem to have driven out the study of documents and
that they have made some problematic critiques of
“the bibliographical paradigm.” User-oriented views
are often contrasted with “the systems driven approach”
which is again associated with the Cranfield
experiments (Hildreth 2001):
Theoretically, the Cranfield model relies almost
entirely on the attractive, but troublesome concept
of relevance. Furthermore, two key assumptions
underlie the Cranfield model: users
desire to retrieve documents relevant to their
search queries and don’t want to see documents
not relevant to their queries, and document
relevance to a query is an objectively discernible
property of the document. Neither of these
two assumptions has stood the test of time, experience
and astute analysis.
The question whether a ‘document relevance to a
query is an objectively discernible property of the
document’ is an epistemological issue, which, according
to Hildreth (2001), is differently perceived in the
Cranfield experiments and in the user-oriented tradi-
Knowl. Org. 35(2008)No.2/No.3
B. Hjørland. What is Knowledge Organization (KO)?
94
tion. Both traditions have, however, almost totally
neglected epistemological theories and thus confused
the concept of ‘users’ and the concept of ‘subjectivity.’
Studying users and their psychology is in user
studies mixed up with studying subjectivity in different
views on knowledge. In the Cranfield experiments
relevance was evaluated by subject experts,
while the user-oriented approach used users for
evaluation (often using the same measures of recall
and precision). It is correct that Cranfield by applying
expert evaluations expected the system to provide
relevant references for all users, i.e. assuming a kind
of a standard user. However, in the user-oriented
framework this is not very different. Algorithms are
often constructed on the basis of an average of users’
evaluations. What has been neglected in both traditions
is to develop different representations of the
same documents to serve different users. Both traditions
are rooted in the positivist understanding that a
representation is objective and neutral and that “one
size fits all.”
2.5 Bibliometric approaches
These approaches are primarily based on using bibliographical
references to organize networks of papers,
mainly by bibliographic coupling (introduced
by Kessler 1963) or co-citation analysis (independently
suggested by Marshakova 1973 and Small
1973). In recent years it has become a popular activity
to construe bibliometric maps as structures of research
fields.
Two considerations are important in considering
bibliometric approaches to KO:
1. The level of indexing depth is partly determined
by the number of terms assigned to each document.
In citation indexing this corresponds to the
number of references in a given paper. On the average,
scientific papers contain 10-15 references,
which provide quite a high level of depth.
2. The references, which function as access points,
are provided by the highest subject-expertise—the
experts writing in the leading journals. This expertise
is much higher than that which library catalogs
or bibliographical databases typically are able
to draw on.
The main advantages and disadvantages in this approach
are summarized in Table 2.
Advantages Disadvantages
– Citations are provided by
highly qualified subject
specialists
– The number of references
reflect the indexing depth
and specificity (average in
scientific papers is about
10 references per article)
– Citation indexing is a
highly dynamic form of
subject representation
– References are distributed
in papers which allows the
utilization of paper structure
in the contextual interpretation
of citations
– Scientific papers form a
kind of self-organizing
system
– The relation between
citations and subject
relatedness is indirect
and somewhat unclear
(related to the
difference between
social organization of
knowledge and intellectual
organization
of knowledge)
– Does not provide
clear logical structure
with mutually exclusive
and collectively
exhaustive classes
– Explicit semantic relations
are not pro-
vided
– Namedropping and
other forms of imprecise
citations may
cause noise
Table 2. Advantages and disadvantages of the bibliometric approach
to KO
Data coverage is an important problem in the bibliometric
approach. Bibliometric maps are extremely
vulnerable to how journals are selected. There is no
objective and neutral way to select journals as data
for bibliometric analysis. If, for example, Knowledge
Organization is excluded from LIS, then classification
researchers like Ranganathan will be relatively
underrepresented, because they are more often cited
in this journal. This does not, however, imply, that
bibliometrics is totally subjective and arbitrary. By
working with different methods and by doing iterative
investigations strong arguments may be made
concerning data coverage.
Schneider (2004) found that bibliometric methods
can be used to provide candidate terms for thesauri.
Bibliometric maps may, however, be considered a
knowledge organizing tool in their own right, one
that can supplement thesauri, whether or not they
can be “verified” by thesauri. Typically bibliometric
maps show networks of cooperating authors, while
thesauri show ontological links. Analytically we may
make a distinction between the intellectual organization
of knowledge and the social organization of
knowledge and it may be argued that bibliometrics is
closer to the social pole. Bibliometric methods may
thus provide supplementary information that is useful
in their own right.
Knowl. Org. 35(2008)No.2/No.3
B. Hjørland. What is Knowledge Organization (KO)?
95
2.6 The domain analytic approach (DA)
The domain analytic approach is an approach formulated
at the beginning of the 1990s as an alternative
to the dominant cognitive view in LIS. Here, it will
be presented more specifically as an alternative to the
other approaches to KO previously discussed.
Domain analysis is a sociological-epistemological
standpoint. The indexing of a given document
should reflect the needs of a given group of users or
a given ideal purpose. In other words, any description
or representation of a given document is more
or less suited to the fulfillment of certain tasks. A
description is never objective or neutral, and the goal
is not to standardize descriptions or make one description
once and for all for different target groups.
The development of the Danish library “KVINFO”
may serve as an example that explains the domainanalytic
point of view. KVINFO was founded by the
librarian and writer Nynne Koch and its history goes
back to 1965. Nynne Koch was employed at the Royal
Library in Copenhagen in a position without influence
on book selection. She was interested in women’s
studies and began personally to collect printed catalog
cards of books in the Royal Library, which were considered
relevant for women’s studies. She developed a
classification system for this subject. Later she became
the head of KVINFO and got a budget for buying
books and journals, and still later, KVINFO became
an independent library. The important theoretical
point of view is that the Royal Library had an official
systematic catalog of a high standard. Normally it is
assumed that such a catalog is able to identify relevant
books for users whatever their theoretical orientation.
This example demonstrates, however, that for a specific
user group (feminist scholars), an alternative way
of organizing catalog cards was important. In other
words: Different points of view need different systems
of organization.
DA is the only approach to KO which has seriously
examined epistemological issues in the field,
i.e. comparing the assumptions made in different approaches
to KO and examining the questions regarding
subjectivity and objectivity in KO. Subjectivity is
not just about individual differences. Such differences
are of minor interest because they cannot be
used as guidelines for KO. What seems important are
collective views shared by many users. A kind of
subjectivity about many users is related to philosophical
positions. In any field of knowledge different
views are always at play. In arts, for example, different
views of art are always present. Such views determine
views on art works, writing on art works,
how art works are organized in exhibitions and how
writings on art are organized in libraries (see Ørom
2003). In general it can be stated that different philosophical
positions on any issue have implications
for relevance criteria, information needs and for criteria
of organizing knowledge.
The representation of a document is made in order
to enable users to make relevant discriminations.
The document should be looked upon with the eyes
of potential users. In a feminist library, for example,
a book should be indexed by anticipating what it
might contribute to feminist scholarship. This may
sound strange, but in many situations this is obvious
and the natural thing to do. This view is known in
the literature as “request oriented indexing.” The
core of indexing is, as stated by Rowley & Farrow to
evaluate a paper’s contribution to knowledge and index
it accordingly (2000, 99):
In order to achieve good consistent indexing,
the indexer must have a thorough appreciation
of the structure of the subject and the nature of
the contribution that the document is making
to the advancement of knowledge.
Or, with the words of Hjørland (1992, 1997): “the
subjects of a document are its informative potentials.”
A more simple way to put it: the indexer
should ask “what use can be made of this particular
document—relative to other documents?”
The kind of information which is judged relevant
for a given task depends on the theory of the person
doing the judgment. If one believes that schizophrenia
is caused by a problematic communication between
mother and child, then studies of family interaction
are evaluated as relevant. If, on the other
hand, one believes schizophrenia is caused by genetic
factors, then the study of genes becomes most relevant.
The criteria used to represent documents are
thus in principle the same criteria that are implied by
current scientific theories. (This is why citation indexes
have an advantage by their extremely dynamic
way of indexing).
The facet analytic point of view takes as the point
of departure the terminology of a given field; little is
said, however, about how the terminology is to be selected.
Domain analysis acknowledges a dilemma, a
kind of chicken-and-egg problem, and a hermeneutic
circle: In order to select the terminology, one needs
to have an understanding of the field. But in order to
get an understanding of a field, one needs to know
Knowl. Org. 35(2008)No.2/No.3
B. Hjørland. What is Knowledge Organization (KO)?
96
about its concepts. The way this has to be solved is
by using iterative methods. DA assumes that different
approaches (or “paradigms”) exist in all domains
of knowledge and have to be identified. They are not
equally distributed in the literature or among the users,
which is why so-called representative samples
cannot be used. (If they were used some important
views would not be properly represented). Different
approaches in a given domain have to be actively
searched for. Any system of knowledge organization
is always biased toward some philosophical position.
There is no neutral platform from which knowledge
can be organized. The task is to mediate between different
views and to develop arguments for a point of
view that is in accordance with the goals and values of
the organization for which the system is developed.
3. Some concepts considered units in KO:
“document,” “information,” and “knowledge”
The field of knowledge organization consists of
some units, elements or entities to be organized and
some relations between those units (e.g., semantic
relations and bibliographic relationships). If we look
at an introductory paper on knowledge organization
such as Anderson (2003), many different suggestions
about what is organized in KO is given
(Anderson 2003, 471 emphasis added):
The description (indexing) and organization
(classification) for retrieval of messages representing
knowledge, texts by which knowledge is
recorded and documents in which texts are embedded.
Knowledge itself resides in minds and
brains of living creatures…. Its organization for
retrieval via short- and long-term memory is a
principal topic of cognitive science. Library and
information science deals with the description
and organization of the artifacts (messages,
texts, documents) by which knowledge (including
feelings, emotions, desires) is represented
and shared with others. These knowledge
resources are often called information resources
as well. Thus ‘knowledge organization’
in the context of library and information science
is a short form of ‘knowledge resources organization’.
This is often called ‘information
organization.’
This quotation provided six different terms (emphasized)
for consideration as candidate terms for the
units in KO. Other views may be found scattered in
different literatures. On the basis of the literature,
many candidate terms may be considered. In this paper,
only three of those terms will be briefly discussed:
Document, information and knowledge.
3.1 Document
Library science was mainly about the organization of
books and book representations on shelves and in
catalogs. Bibliography included articles and other
kinds of documents listed in bibliographies. Archives
organize “records,” while museums organize physical
objects. The documentalists made a generic concept
“document” to include not just books, articles, “records”
and objects such as globes, but any kind of
material indexed to serve as some kind of documentation,
including pictures, maps and globes. Even
animals were considered documents (if captured and
kept in a zoo). The concept of document is important
but lost much influence with the entrance of
computers in the 1950s, but has recently had an important
renaissance.
3.2 Information
Computer scientists ignored earlier conceptual work
in the fields of library science and documentation
and just talked about “information storage and retrieval.”
To talk about information rather than
documents may have raised the status of the dusty
profession of library science/documentation, as suggested
by Spang-Hanssen (2001). Intellectually,
however, it has brought much confusion and may
have misled KO from its proper theoretical basis.
Experiments with “information retrieval" in the
1950s-1960s were mainly based on bibliographical
databases. The transformation to electronic media
did not change the nature of what was represented.
The use of the term “information” was associated
with the belief that Shannon’s “information theory”
was a long-needed answer to a theory also about libraries
and scholarly communication. The expectations
were never met, however, and the talk about information
rather than documents has not strengthened
the theoretical basis of the field (although, of
course information theory is valuable in computer
science for technical problems such as measuring the
storage capacity of disks). Documents are more related
to the concept and theory of semiotics (the
field about signs), which may turn out to be a more
fruitful theoretical frame for KO.
Knowl. Org. 35(2008)No.2/No.3
B. Hjørland. What is Knowledge Organization (KO)?
97
3.3 Knowledge
The term KO originated in the library field. It seems
to have been established around 1900 by people like
Charles A. Cutter and Ernest Cushington Richardson
and stabilized by W. C. Berwick Sayers and
Henry Bliss. Bliss’ book (1929) The organization of
knowledge and the system of the sciences represents
one of the main intellectual contributions in the
field. All of these authors argued that book classification
is based on knowledge organization as it appears
in science and scholarship. The best way to organize
books in libraries (and document representations
in bibliographies) was to make the library classification
reflect a scientific classification which, in
turn, was supposed to reflect the nature of reality.
Cutter, Bliss, and other important classification
researchers from the period of the second half of the
19th
century and the first half of the 20th
century, realized
that what is organized cannot be taken as absolute
truth. However, Bliss believed that knowledge
was relatively safe and true, which is why a kind of
consensus could be established. Because of this, Bliss
and his contemporary chose the term “knowledge
organization,” “knowledge” understood in the Platonic
tradition as “verified, true belief.”
In his preface to Bliss (1929), the philosopher
John Dewey wrote (Dewey 1929, viii):
A classification of books to be effective on the
practical side must correspond to the relationships
of subject-matters, and this correspondence
can be secured only as the intellectual, or
conceptual, organization is based upon the order
inherent in the fields of knowledge, which
in turn mirrors the order of nature.
This quotation is in accordance with the traditional
view of knowledge as a neutral and objective reflection
of reality. It is, however, a bad representation of
John Dewey’s pragmatic view of knowledge and of
classification, as demonstrated by another quotation
(Dewey 1920/1948, 151-54):
No sensible person tries to do everything. He
has certain main interests and leading aims by
which he makes his behavior coherent and effective.
To have an aim is to limit, select, concentrate,
group. Thus a basis is furnished for
selecting and organizing things according as
their ways of acting are related to carrying forward
pursuit. Cherry trees will be differently
grouped by woodworkers, orchardists, artists,
scientists and merry-makers. To the execution
of different purposes different ways of acting
and re-acting on the part of trees are important.
Each classification may be equally sound when
the difference of ends is borne in mind.
Nevertheless there is a genuine objective
standard for the goodness of special classifications.
One will further the cabinetmaker in
reaching his end while another will hamper
him. One classification will assist the botanist
in carrying on fruitfully his work of inquiry,
and another will retard and confuse him. The
teleological theory of classification does not
therefore commit us to the notion that classes
are purely verbal or purely mental. Organization
is no more merely nominal or mental in
any art, including the art of inquiry, than it is in
a department store or railway system. The necessity
of execution supplies objective criteria.
Things have to be sorted out and arranged so
that their grouping will promote successful action
for ends. Convenience, economy and efficiency
are the bases of classification, but these
things are not restricted to verbal communication
with others nor to inner consciousness;
they concern objective action. They must take
effect in the world.
At the same time, a classification is not a
bare transcript or duplicate of some finished
and done-for arrangement pre-existing in nature.
It is rather a repertory of weapons for attack
upon the future and the unknown. For
success, the details of past knowledge must be
reduced from bare facts to meanings, the fewer,
simpler and more extensive the better.
This quotation clearly demonstrates that John
Dewey did not accept the mirror metaphor of
knowledge, or, as he expressed it: “a bare transcript
or duplicate of some finished and done-for arrangement
pre-existing in nature.”
For KO this issue is important. Two different
views of knowledge can be contrasted:
1. “Positivist view”: Knowledge and KO as “a bare
transcript or duplicate of some finished and donefor
arrangement pre-existing in nature.”
2. “Pragmatic view”: Knowledge and KO as something
constructed to deal with some human needs
and interests.
Knowl. Org. 35(2008)No.2/No.3
B. Hjørland. What is Knowledge Organization (KO)?
98
The pragmatist view of knowledge is also connected
with “fallibilism,” the view that scientific research is
never to be taken finally proved, that new evidence
may change scientific beliefs. The implication of fallibilism
is that we cannot understand the documents as
representing knowledge, as traditionally understood.
We should not talk about knowledge or knowledge
organization, but about knowledge claims and the organization
of knowledge claims. The implication is
that each knowledge claim is supported by and connected
with arguments, theories and world views. If
this is recognized by the people performing KO, then
the activity is not based on “positivism.”
4. Fields contributing to knowledge organization
Knowledge Organization is not just something the
LIS-profession can do without considering research
in other domains, for example, computer science,
linguistics and natural language processing, theory of
knowledge, theory of social organization etc. In particular
an understanding of the nature of knowledge,
cognition, language and social organization is decisive
for the understanding of KO and thus for the
ability to design, evaluate and use knowledge organizing
processes and knowledge organizing systems.
Many fields may have an interest in the defining
questions of knowledge organization or may be considered
related disciplines. This issue has already
been introduced above, for example, the role of the
sociology of knowledge, the single sciences and
metaphysics/ontology.
A few words about the concept of discipline in relation
to this issue: much knowledge is today scattered
in different disciplines. Library schools have
traditionally educated librarians and information
specialists, schools of language for special purposes
have educated translators, business schools have
educated information managers, schools of computer
science have educated software engineers etc.
In many ways much of what they have been working
with is based on the same kind of theoretical knowledge.
Their separation has posed a problem rather
than provided a fruitful development of separate
fields. This journal (Knowledge Organization) sometimes
publishes information related to the field of
terminology, but this is an exception that confirms
the rule that the two fields are separated. In each discipline,
there is a need for theoretical clarification
about the fundamental problems in knowledge, cognition,
communication, language and social organization,
which are common to all these disciplines.
Our journal, Knowledge Organization, has the
subtitle: International Journal. Devoted to Concept
Theory, Classification, Indexing, and Knowledge Representation.
Each of these fields may be studied from
different perspectives. First, they may be studied
from different disciplinary perspectives. Concepts,
for example, may be studied by psychology, by linguistics,
by philosophy, by sociology, by artificial intelligence
and so on. Each of these fields tends to
emphasize different aspects of concepts. At the same
time, however, each of those fields struggles with the
same fundamental problems regarding the nature of
concepts. Second, there are basic (epistemological)
theories of concepts that are common to all those
fields and within each field competing for attention.
It is this epistemological level that is most important.
If a strong theory is developed at this level, all
the involved disciplines will benefit in a very important
way.
Let us consider linguistics as an example. First,
linguistics is a discipline (studying language) but
language is also studied by, for example psychology,
and sociology. Linguistics should be extremely important
for LIS and KO because of the dominance of
texts in libraries and because most intermediating activity
is based on language. The case is, however, that
linguistic research is very seldom cited in the literature
of LIS (cf. Warner 1991). Why is this?
The influential computer scientist Gerald Salton
expressed pessimism concerning the usefulness of
linguistics in information science. In the words of
the Danish linguist and information scientist Henning
Spang-Hanssen (1974, 17, translated by BH):
In this connection it is important to realize that
the points of view, which have been dominant
within linguistics in the last 10-15 years, in particular
in the USA (i.e. Noam Chomsky's
school of generative grammar) have not had
practical influence worth mentioning in relation
to natural language processing. In its theoretical
foundation and in the technicalities (such as the
writing of rules in algorithmic form) exist important
similarities between generative grammar
and electronic data processing. Natural language
processing seems, however, in practice still to
depend on traditional categories of grammar
and traditionally formed dictionaries. This
demonstrates in my opinion the problems related
to automation of text—as opposed to
problems related to automation of mathematical
computations—are fundamental and thus can-
Knowl. Org. 35(2008)No.2/No.3
B. Hjørland. What is Knowledge Organization (KO)?
99
not be eliminated just by computer-oriented
versions of linguistics.
I thus share with Gerald Salton his pessimism
about the usefulness of recent linguistics
in relation to automated documentation. However,
Salton seems to identify linguistics with
modern American linguistics and thus to miss
the knowledge, which was gained before generative
grammar evolved or which was gained in
other countries such as Scandinavia.
In order to understand the relation between linguistics
and LIS it is thus important to understand that
both fields are influenced by changing epistemological
views and interdisciplinary trends. Epistemology
is simply a deeper way to understand both fields.
This situation unfortunately makes it more difficult
for all parties, including knowledge organization. In
order to draw from related fields such as linguistics,
we simply have to find a satisfactory metatheory before
we can do so. In line with what is written earlier
in this paper, I find that such a metatheory must be
related to pragmatism.
5. Conclusion
Knowledge Organization is one among many contemporary
fields which try to play a role in the future
environments of communicating and exchanging
knowledge. Among the competitors are Knowledge
Management and Computer Science. Much
knowledge may be shared among such fields, but is
important for each field to develop a clear identity
and a history of its own. KO has in particular been
connected with LIS and has aimed at supporting
learning and research activities, which may be one of
the important pillars on which to base the field. Another
related pillar is the concept of knowledge and
theories of knowledge. Knowledge Organization
may have a valuable theoretical base in theory of
knowledge, which may be the reason why we should
stick to this label as the name of our field.
References
Anderson, J.D. 2003. Organization of knowledge. In
Feather, John and Sturges, Paul, eds., International
encyclopedia of information and library science. 2nd
ed. London: Routledge, 471-90.
Bawden, David. 2007. The doomsday of documentation?
Journal of documentation 63:2, (editorial).
Bliss, Henry Evelyn. 1929. The organization of
knowledge and the system of the sciences. With an
introduction by John Dewey. New York: Henry
Holt and Co.
Bliss, Henry Evelyn. 1935. A system of bibliographic
classification. New York: H. W. Wilson.
Broughton, Vanda. 2004. Essential classification.
London : Facet Publishing.
Dupré, J. 2006. Scientific classification. Theory, culture
& society 23:2-3, 30-32.
Broughton, Vanda, Hansson, Joacim, Hjørland,
Birger and López-Huertas, Maria J. 2005, Knowledge
organisation: Report of working group 7. In
Kajberg, L. and Lørring, L., eds., European curriculum
reflections on education in library and information
science, Royal School of Library and Information
Science, Copenhagen. Available at http://
www.db.dk/LIS-EU/workshop.asp
Cole, Jonathan R. and Cole, Stephen. 1973. Social
stratification in science. Chicago, IL: University of
Chicago Press.
Dewey, John. 1929. Introduction. In Bliss, Henry
Evelyn, The organization of knowledge and the system
of the sciences. New York: Henry Holt and
Company.
Dewey, John. 1920/1948. Reconstruction in philosophy.
Enlarged edition. New York: Beacon, 1948.
(Original work published 1920).
Dolby, R. G. Alex. 1979. Classification of the sciences:
the nineteenth century tradition. In Ellen,
R. F. & Reason, D., eds., Classifications in their social
contexts. New York: Academic Press, 167-93.
Dupré, John. 2006. Scientific classification. Theory,
culture & society 23:2-3, 30-32.
Ellis, David. 1996. Progress and problems in information
retrieval. London: Library Association Pub-
lishing.
Ereshefsky, Marc. 2000. The poverty of the Linnaean
hierarchy: a philosophical study of biological taxonomy.
Cambridge: Cambridge University Press.
Frohmann, Bernd. 1994. The social construction of
knowledge organization: the case of Melvil
Dewey. In Albrechtsen, Hanne and Oernager, Susanne,
eds., Knowledge organization and quality
management: Proceedings of the Third international
ISKO Conference 20-24 June 1994 Copenhagen.
Frankfurt/Main: INDEKS Verlag, 109-17.
Garfield, Eugene. 1975. The “other” immortal: a
memorable day with Henry E. Bliss. Current contents
15, 7-8. Reprinted in: Essays of an information
scientist 2 (1974-76), 250-251. Available at
Knowl. Org. 35(2008)No.2/No.3
B. Hjørland. What is Knowledge Organization (KO)?
100
http://www.garfield.library.upenn.edu/essays/v2p
250y1974-76.pdf
Gruzd, Anatoliy. 2007. Book review of ‘New Directions
in Cognitive Information Retrieval’. Journal
of the American Society for Information Science and
Technology 58:5, 758-60.
Hildreth, Charles R. 2001. Accounting for users' inflated
assessments of on-line catalogue search performance
and usefulness: an experimental study.
Information research 6:2. Available at http://
InformationR.net/ir/6-2/paper101.html
Hjørland, Birger. 1992. The concept of “subject” in
information science. Journal of documentation
48:2, 172-200. Available at http://www.db.dk/bh/
Core%20Con-
cepts%20in%20LIS/1992JDOC_Subject.PDF
Hjørland, Birger. 1997. Information seeking and subject
representation. An activity-theoretical approach
to information science. Westport & London:
Greenwood Press.
Hjørland, Birger. 2005ff. Lifeboat for Knowledge
Organization. Available at http://www.db.dk/bh/
lifeboat%5Fko/home.htm
Hjørland, Birger. 2007a. Arguments for 'the bibliographical
paradigm'. Some thoughts inspired by
the new English edition of the UDC. Information
research 12:4, paper colis06. Available at http://
informationr.net/ir/12-4/colis/colis06.html
Hjørland, Birger. 2007b. Semantics and knowledge
organization. Annual review of information science
and technology 41, 367-405.
Hjørland, Birger & Nissen Pedersen, Karsten. 2005.
A substantive theory of classification for information
retrieval. Journal of documentation 61:5, 582-
97. Available at http://www.db.dk/bh/Core%20
Concepts%20in%20LIS/Hjorland%20&%20
Nissen.pdf
Hulme, E. Wyndam 1911. Principles of book classification.
Library Association record 13: Oct. 1911,
354-58; Nov. 1911, 389-94; and Dec. 1911, 444-49.
Kessler, Myer Mike. 1963. Bibliographic coupling between
scientific papers. American documentation
14, 10-25.
La Barre, Kathryn. 2006. The use of faceted analyticosynthetic
theory as revealed in the practice of website
construction and design. Ph.D. dissertation, Indiana
University.
Marshakova, I. V. 1973. A system of document connection
based on references. Scientific and technical
information serial of VINITI, 6:2, 3-8.
Martyn, J. 1964. Bibliographic coupling. Journal of
documentation 20:4, 236.
Mayr, Ernst. 1982. The growth of biological thought:
diversity, evolution, and inheritance. Cambridge,
Mass.: The Belknap Press of Harvard University
Press.
Miksa, Francis. 1998. The DDC, the universe of
knowledge, and the post-modern library. Albany,
NY: Forest Press.
Mishler, Brent D. 2000. Deep phylogenetic relationships
among “plants” and their implications for
classification. Taxon 49:4, 661-683.
Moss, R. 1964. Categories and relations: origins of
two classification theories. American documentation,
296-301.
Oleson, Alexandra & Voss, John, eds. 1979. The organization
of knowledge in modern America, 1860-
1920. Baltimore: Johns Hopkins University Press.
Ranganathan, Shiyali Ramamrita. 1951. Philosophy of
library classification. Copenhagen: E. Munksgaard.
Rowley, Jennifer E. & Farrow, John. 2000. Organizing
knowledge: an introduction to managing access
to information. 3rd
ed. Alderstot: Gower Publishing
Company.
Schneider, Jesper W. 2004. Verification of bibliometric
methods' applicability for thesaurus construction.
Ph.D. dissertation, Royal School of Library and
Information Science, Aalborg. Available at http://
biblis.db.dk/archimages/199.pdf
Small, Henry. 1973. Co-citation in the scientific literature:
a new measurement of the relationship
between two documents. Journal of the American
Society of Information Science, 24:4, 265-269.
Spang-Hanssen, Henning. 1974. Kunnskapsorganisasjon,
informasjonsgjenfinning, automatisering
og språk. In Kunnskapsorganisasjon og informasjonsgjenfinning.
Oslo: Riksbibliotektjenesten, 11–
61. Available at http://www.db.dk/bh/Core%20
Concepts%20in%20LIS/Spang%5FHanssen%
5F1974.pdf
Spang-Hanssen, Henning. 2001 [written 1970]. How
to teach about information as related to documentation.
Human IT 1, 125-143. Available at http://
www.hb.se/bhs/ith/1-01/hsh.htm
Sparck Jones, Karen 2005. Revisiting classification
for retrieval. Journal of documentation 61:5, 598-
601. [Reply to Hjørland & Nissen Pedersen,
2005]. Available http://www.db.dk/bh/Core%
20Concepts%20in%20LIS/Sparck%20Jones%5
Freply%20to%20Hjorland%20&%20Nissen.pdf
Warner, A. J. 1991. Quantitative and qualitative assessments
of the impact of linguistic theory on information
science. Journal of the American Society
for Information Science 42:1, 64-71.
Knowl. Org. 35(2008)No.2/No.3
B. Hjørland. What is Knowledge Organization (KO)?
101
Warner, Julian 2002. Forms of labour in information
systems. Information research 7:4. Available at
http://informationr.net/ir/7-4/paper135.html
Warner, Julian 2007. Description and search labor for
information retrieval. Journal of the American Society
of Information Science and Technology 58:12,
1783–90.
Ørom, Anders 2003. Knowledge organization in the
domain of art studies: History, transition and
conceptual changes. Knowledge organization 30:
3/4, 128-43.