25:
485:
This is particularly problematic when the search question involves terms that are sufficiently tangential to the subject area such that the indexer might have decided to tag it using a different term (but the searcher might consider the same). Essentially, this can be avoided only by an experienced
297:
are chosen and organized by trained professionals (including librarians and information scientists) who possess expertise in the subject area. Controlled vocabulary terms can accurately describe what a given document is actually about, even if the terms themselves do not occur within the document's
501:
Controlled vocabularies may become outdated rapidly in fast developing fields of knowledge, unless the preferred terms are updated regularly. Even in an ideal scenario, a controlled vocabulary is often less specific than the words of the text itself. Indexers trying to choose the appropriate index
516:
Word choice in chosen vocabularies is not neutral, and the indexer must carefully consider the ethics of their word choices. For example, traditionally colonialist terms have often been the preferred terms in chosen vocabularies when discussing First
Nations issues, which has caused controversy.
614:
It is unlikely that a single metadata scheme will ever succeed in describing the content of the entire Web. To create a
Semantic Web, it may be necessary to draw from two or more metadata systems to describe a Web page's contents. The eXchangeable Faceted Metadata Language (XFML) is designed to
505:
The use of controlled vocabularies can be costly compared to free text searches because human experts or expensive automated systems are necessary to index each entry. Furthermore, the user has to be familiar with the controlled vocabulary scheme to make best use of the system. But as already
489:
Another possibility is that the article is just not tagged by the indexer because indexing exhaustivity is low. For example, an article might mention football as a secondary focus, and the indexer might decide not to tag it with "football" because it is not important enough compared to the main
362:
When indexing a document, the indexer also has to choose the level of indexing exhaustivity, the level of detail in which the document is described. For example, using low indexing exhaustivity, minor aspects of the work will not be described with index terms. In general the higher the indexing
554:
databases appeared; these databases contain the full text of the index articles as well as the bibliographic information. Online bibliographic databases have migrated to the
Internet and are now publicly available; however, most are proprietary and can be expensive to use. Students enrolled in
276:
Subject headings tend to use more pre-coordination of terms such that the designer of the controlled vocabulary will combine various concepts together to form one preferred subject heading. (e.g., children and terrorism) while thesauri tend to use singular direct terms. Thesauri list not only
626:
define the concepts and relationships (terms) used to describe a field of interest or area of concern. For instance, to declare a person in a machine-readable format, a vocabulary is needed that has the formal definition of "Person", such as the Friend of a Friend
196:(a subject heading system that uses a controlled vocabulary), preferred terms—subject headings in this case—have to be chosen to handle choices between variant spellings of the same word (American versus British), choice among scientific and popular terms (
461:
Compared to free text searching, the use of a controlled vocabulary can dramatically increase the performance of an information retrieval system, if performance is measured by precision (the percentage of documents in the retrieval list that are actually
497:
On the other hand, free text searches have high exhaustivity (every word is searched) so although it has much lower precision, it has potential for high recall as long as the searcher overcome the problem of synonyms by entering every combination.
328:
Lastly the amount of pre-coordination (in which case the degree of enumeration versus synthesis becomes an issue) and post-coordination in the system is another important issue. Controlled vocabulary elements (terms/phrases) employed as
545:. Subsequently, for-profit firms (called Abstracting and indexing services) emerged to index the fast-growing literature in every field of knowledge. In the 1960s, an online bibliographic database industry developed based on dialup
469:
In some cases controlled vocabulary can enhance recall as well, because unlike natural language schemes, once the correct preferred term is searched, there is no need to search for other terms that might be synonyms of that term.
277:
equivalent terms but also narrower, broader terms and related terms among various preferred and non-preferred (but potentially synonymous) terms, while historically most subject headings did not. For example, the
272:
Because of the card catalog system, subject headings tend to have terms that are in indirect order (though with the rise of automated systems this is being removed), while thesaurus terms are always in direct
188:
between concepts and preferred terms. In short, controlled vocabularies reduce unwanted ambiguity inherent in normal human languages where the same concept can be given different names and ensure consistency.
631:) vocabulary, which has a Person class that defines typical properties of a person including, but not limited to, name, honorific prefix, affiliation, email address, and homepage, or the Person vocabulary of
549:
networking. These services were seldom made available to the public because they were difficult to use; specialist librarians called search intermediaries handled the searching job. In the 1980s, the first
325:
When selecting terms for a controlled vocabulary, the designer has to consider the specificity of the term chosen, whether to use direct entry, inter consistency and stability of the language.
567:. The use of controlled vocabulary ensures that everyone is using the same word to mean the same thing. This consistency of terms is one of the most important concepts in
370:
as a means of access to documents has become popular. This involves using natural language indexing with an indexing exhaustively set to maximum (every word in the text is
591:
Web searching could be dramatically improved by the development of a controlled vocabulary for describing Web pages; the use of such a vocabulary could culminate in a
374:). These methods have been compared in some studies, such as the 2007 article, "A Comparative Evaluation of Full-text, Concept-based, and Context-sensitive Search."
555:
colleges and universities may be able to access some of these services without charge; some of these services may be accessible without charge at a public library.
537:. In the 1950s, government agencies began to develop controlled vocabularies for the burgeoning journal literature in specialized fields; an example is the
144:. Controlled vocabulary schemes mandate the use of predefined, preferred terms that have been preselected by the designers of the schemes, in contrast to
822:
269:
Subject headings tend to be broader in scope describing whole books, while thesauri tend to be more specialized covering very specific disciplines.
894:
1199:
608:
650:
To use machine-readable terms from any controlled vocabulary, web designers can choose from a variety of annotation formats, including RDFa,
172:
units of information (document or work) so that they may be more easily retrieved by a search. Controlled vocabularies solve the problems of
333:, to aid in the content identification process of documents, or other information system entities (e.g. DBMS, Web Services) qualifies as
898:
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542:
307:
1194:
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89:
502:
terms might misinterpret the author, while this precise problem is not a factor in a free text, as it uses the author's own words.
454:
therefore will retrieve documents that are about several completely different sports. Controlled vocabulary solves this problem by
61:
1219:
281:
itself did not have much syndetic structure until 1943, and it was not until 1985 when it began to adopt the thesauri type term "
319:
42:
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Links to examples of thesauri and classification schemes used in the domain of
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Controlled vocabularies are often claimed to improve the accuracy of free text searching, such as to reduce
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Numerous methodologies have been developed to assist in the creation of controlled vocabularies, including
708:
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486:
user of controlled vocabulary whose understanding of the vocabulary coincides with that of the indexer.
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349:
Controlled indexing language – only approved terms can be used by the indexer to describe the document
1150:
482:, in that it will fail to retrieve some documents that are actually relevant to the search question.
439:
1098:
900:
Introduction to controlled vocabularies: terminology for art, architecture, and other cultural works
787:
Introduction to controlled vocabularies: terminology for art, architecture, and other cultural works
696:
538:
358:
Free indexing language – any term (not only from the document) can be used to describe the document
303:
82:
266:
by catalogers while thesauri were used by indexers to apply index terms to documents and articles.
258:. While the differences between the two are diminishing, there are still some minor differences.
615:
enable controlled vocabulary creators to publish and share metadata systems. XFML is designed on
564:
490:
focus. But it turns out that for the searcher that article is relevant and hence recall fails. A
35:
254:
There are two main kinds of controlled vocabulary tools used in libraries: subject headings and
735: – Transformation aided by semantic equivalence statements within a controlled vocabulary.
616:
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355:
indexing language – any term from the document in question can be used to describe the document
311:
903:. Getty Research Institute (1st ed.). Los Angeles, California: Getty Research Institute.
1214:
839:
924:
Moskovitch, Robert; Martins, Susana B.; Behiri, Eytan; Weiss, Aviram; Shahar, Yuval (2007).
699: – Extraction of named entity mentions in unstructured text into pre-defined categories
1229:
693: – Mark-up language – or grammar – for controlled vocabularies developed by IMS Global
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263:
227:(terms chosen by considering the structure, scope of the controlled vocabulary).
129:
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124:
provide a way to organize knowledge for subsequent retrieval. They are used in
455:
423:
330:
169:
1183:
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1006:
949:
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563:
In large organizations, controlled vocabularies may be introduced to improve
687: – List of words used by lexicographers to write dictionary definitions
506:
mentioned, the control of synonyms, homographs can help increase precision.
967:
785:
702:
623:
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592:
580:
530:
431:
705: – System of names or terms in a particular field of arts or sciences
595:, in which the content of Web pages is described using a machine-readable
533:, the study and classification of books. They were initially developed in
246:
to ensure that each preferred term or heading refers to only one concept.
1174:
717:
640:
600:
427:
294:
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941:
644:
636:
632:
405:
231:
173:
603:
Initiative. An example of a controlled vocabulary which is usable for
983:"Controlled Vocabularies: Past, Present and Future of Subject Access"
551:
463:
223:(what terms are generally used in the literature and documents), and
185:
662:
serializations (RDF/XML, Turtle, N3, TriG, TriX) in external files.
24:
690:
596:
576:
334:
282:
255:
181:
177:
635:. Similarly, a book can be described using the Book vocabulary of
262:
Historically, subject headings were designed to describe books in
1048:
720: – Academic discipline studying terms and their general uses
655:
458:
the documents in such a way that the ambiguities are eliminated.
286:
583:
instead of slightly different ones to refer to the same thing.
414:
165:
790:(1st ed.). Los Angeles, Calif: Getty Research Institute.
575:, where effort is expended to use the same word throughout a
230:
Controlled vocabularies also typically handle the problem of
923:
865:"Controlled Vocabularies | Librarians | Library of Congress"
599:
scheme. One of the first proposals for such a scheme is the
1068:
628:
546:
1146:
675: – Unique headings used for bibliographic information
478:
A controlled vocabulary search may lead to unsatisfactory
215:
Choices of preferred terms are based on the principles of
1094:
755:
Links to examples of thesauri and classification schemes.
363:
exhaustivity, the more terms indexed for each document.
160:, controlled vocabulary is a carefully selected list of
930:
Journal of the
American Medical Informatics Association
713:
Pages displaying short descriptions of redirect targets
494:
would automatically pick up that article regardless.
408:. Worldwide the most popular of these team sports is
386:
items in the retrieval list. These irrelevant items (
298:
text. Well known subject heading systems include the
151:
728:
Pages displaying wikidata descriptions as a fallback
586:
49:. Unsourced material may be challenged and removed.
643:vocabulary, an event with the Event vocabulary of
345:There are three main types of indexing languages.
1181:
390:) are often caused by the inherent ambiguity of
1121:"Dublin Core Metadata Element Set, Version 1.1"
148:vocabularies, which have no such restriction.
895:"3. Relationships in Controlled Vocabularies"
711: – Specification of a conceptualization
1175:Directory of Linked Open Vocabularies (LOV)
404:is the name given to a number of different
558:
308:United States National Library of Medicine
249:
987:Cataloging & Classification Quarterly
957:
109:Learn how and when to remove this message
892:
840:"Karl Fast, Fred Leise and Mike Steckel"
779:
639:and general publication terms from the
238:has to be qualified to refer to either
234:with qualifiers. For example, the term
1182:
1049:eXchangeable Faceted Metadata Language
782:"2. What Are Controlled Vocabularies?"
219:(what terms users are likely to use),
1200:Library cataloging and classification
1069:"The Person vocabulary of Schema.org"
980:
525:Controlled vocabularies, such as the
340:
1147:"The Event vocabulary of Schema.org"
775:
773:
681: – Subset of a natural language
527:Library of Congress Subject Headings
194:Library of Congress Subject Headings
47:adding citations to reliable sources
18:
1127:from the original on 16 August 2013
1095:"The Book vocabulary of Schema.org"
279:Library of Congress Subject Heading
13:
1153:from the original on 13 March 2015
1101:from the original on 11 March 2015
691:IMS Vocabulary Definition Exchange
412:, which also happens to be called
314:. Well known thesauri include the
152:In library and information science
14:
1241:
1168:
1075:from the original on 28 July 2015
770:
543:U.S. National Library of Medicine
212:), among other difficult issues.
204:), and choices between synonyms (
1195:Information retrieval techniques
724:Universal Data Element Framework
587:Semantic web and structured data
529:, are an essential component of
23:
1139:
1113:
1087:
1061:
1041:
1021:
981:Smith, Catherine (2021-04-03).
875:from the original on 2019-11-16
846:from the original on 2017-11-17
733:Vocabulary-based transformation
622:Controlled vocabularies of the
535:library and information science
520:
418:in several countries. The word
158:library and information science
34:needs additional citations for
1220:Ontology (information science)
974:
917:
886:
857:
832:
820:A taxonomy primer // dead link
812:
758:
746:
316:Art and Architecture Thesaurus
142:knowledge organization systems
16:Method of organizing knowledge
1:
999:10.1080/01639374.2021.1881007
740:
726: – controlled vocabulary
377:
7:
893:Harpring, Patricia (2010).
780:Harpring, Patricia (2010).
709:Ontology (computer science)
679:Controlled natural language
665:
473:
10:
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300:Library of Congress system
440:Australian rules football
1205:Knowledge representation
697:Named-entity recognition
541:(MeSH) developed by the
539:Medical Subject Headings
394:. Take the English word
304:Medical Subject Headings
1210:Technical communication
1190:Controlled vocabularies
869:The Library of Congress
765:Controlled Vocabularies
753:Controlled Vocabularies
565:technical communication
559:Technical communication
250:Types used in libraries
122:Controlled vocabularies
58:"Controlled vocabulary"
617:faceted classification
511:faceted classification
466:to the search topic).
306:(MeSH) created by the
202:Periplaneta americana
842:. 16 December 2002.
573:knowledge management
410:association football
192:For example, in the
168:, which are used to
43:improve this article
1225:Information science
942:10.1197/jamia.M1953
685:Defining vocabulary
422:is also applied to
1054:2012-02-08 at the
1034:2007-05-08 at the
825:2016-03-05 at the
658:in the markup, or
605:indexing web pages
341:Indexing languages
225:structural warrant
910:978-1-60606-150-3
797:978-1-60606-018-6
673:Authority control
569:technical writing
448:Canadian football
436:American football
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492:free text search
392:natural language
368:free text search
366:In recent years
353:Natural language
264:library catalogs
221:literary warrant
146:natural language
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32:This article
30:
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20:
1215:Semantic Web
1155:. Retrieved
1141:
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703:Nomenclature
649:
624:Semantic Web
621:
619:principles.
613:
593:Semantic Web
590:
581:organization
562:
531:bibliography
524:
521:Applications
515:
508:
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432:rugby league
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283:Broader term
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242:or the game
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217:user warrant
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41:Please help
36:verification
33:
1230:Identifiers
718:Terminology
641:Dublin Core
601:Dublin Core
428:rugby union
406:team sports
322:Thesaurus.
287:Narrow term
1184:Categories
879:2018-05-22
850:2014-09-15
741:References
645:Schema.org
637:Schema.org
633:Schema.org
384:irrelevant
378:Advantages
232:homographs
206:automobile
174:homographs
140:and other
138:taxonomies
69:newspapers
1015:233205938
1007:0163-9374
950:1067-5027
806:456174098
552:full text
198:cockroach
186:bijection
182:polysemes
128:schemes,
99:June 2012
1157:13 March
1151:Archived
1131:13 March
1125:Archived
1105:13 March
1099:Archived
1079:13 March
1073:Archived
1052:Archived
1032:Archived
1029:Metacrap
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