LCSH Introduction (Tulane Cataloging)

Introduction to LC Subject Headings

Document sections

Introduction Limitations and caveats
Basic approach and principles Verifying LCSH
Forms and construction


This general introduction to Library of Congress Subject Headings (LCSH) is based on a trainer’s notes used in introducing copy cataloguers to the basics of LCSH.  These notes cover general principles of LCSH and general points on the valid construction of LCSH.  The process of subject analysis – figuring out the topic, topics, or genre of a work – is not covered here.  The focus is primarily on the cataloguing of non-literary works.

These introductory notes have been designed to be used in conjunction with the reading of sections of Subject Cataloging Manual:  Subject Headings -- especially:

H180 -- Assigning and constructing subject headings
H80 -- Order of subject headings
H1075 -- Subdivisions
H1095 -- Free-floating subdivisions
H1100-H1200 -- Sections covering pattern heading categories.

Additional local documents about subject headings are available through our local documentation list under “Subject headings.”

Basic approach and principles

Provision of subject access Number of subject headings
Subject cataloguing vs indexing Order of subject headings
Principle of specificity

A.            Provision of subject access.  Subject headings are access points with standardised forms of terms, names, and uniform titles that reflect the topic or genre of a work -- what a work is about or the form or type of the work.  People with interest in a particular topic, not with a specific title or author in mind, should be able to use to find records for relevant works.  Personal, corporate, and geographic name headings, as well as uniform title headings, may be used as subject headings, when a work is about the person, body, place, or other work.


B.            Subject cataloguing vs. indexing:  LC’s  subject heading system is intended to reflect major subjects -- generally those covered in 20% of the text or more (i.e., about 1/5 of the text – you don't need to count pages specifically, but you may want to scan contents).  There are some exceptions, if a named person or entity is particularly stressed.


Assigning subject headings, therefore, is not the same as detailed indexing, which may cover a topic or name that appears only once, briefly, in a work.   A set of subject headings just constitutes a concise, standardised summary of what a work is about.  One common temptation of cataloguers-in-training is to try to provide subject access that is too detailed.

C.            Principle of specificity:  As LC states -- "Assign headings that are as specific as the topics they cover."  In other words, generally don't assign broad, general headings when dealing with specific aspect of that topic.  However, a valid heading that is as specific as the topic is not always available.  Try to be as specific as you can while still covering the topic.


Groups of subtopics of overarching general topic: 


1.             If 3 or fewer subtopics of general topic are discussed:


a.             If the subtopics cumulatively represent the entire topic (i.e., there are no significant aspects of the broader topic that are not covered in the work), assign a heading for the broader topic.


E.g.         Book on vertebrate and invertebrate animals; animals are either vertebrate or invertebrate.


Assign:  Animals


not                          Vertebrates



b.             If the subtopics cumulatively represent only part of the entire topic (i.e., there are significant aspects of the broader topic that are not covered in the work), assign a heading for each of the subtopics.


E.g.         Book on mice and rats, both sub-categories of rodents; there are types of rodents other than mice and rats.


Assign:  Mice



not                          Rodents


2.             If more than 3 subtopics of general topic are discussed:  assign a heading for the broader topic.  (There are occasional exceptions, if 4 subtopics of a very broad topic are discussed.)


E.g.         Book on mice, elephants, bears, and deer.


Assign:  Mammals


not          4 headings, each representing the different type of mammal.


D.            Number of subject headings:  The number of subject headings assigned varies from work to work.  Sometimes one is adequate; sometimes several are needed.  


1.             Many works deal with more than one focussed topic – a group of related topics.  Each major topic deserves a subject heading.


2.             You often need multiple subject headings to bring out multiple facets of the same topic.  For example, for a work about an economic problem in a given place:  you may end up with a heading for the type of problem (in that place if the rules allow geographic subdivision of that topical heading), and a heading for the place, subdivided by "Economic conditions." 


NB:  Subject heading strings (see below) are another way to try to bring out multiple facets or subfacets of a subject.


3.             A work may deal with a topic on more than one level, e.g., a general discussion of a concept, with case studies that illustrate the concept in a specific context; a study of a social phenomenon, including a specific examination of the history of that phenomenon in a particular place.  Headings should reflect different levels if there is at least 20% of the work devoted to each level.


E.g.                         In the same record:


Women $z Nicaragua.



6 subject headings or so are considered adequate for most books.  There should rarely be more than 10 subject headings (we have made some exceptions, usually with very specialised materials such as theses and detailed anthropological and archaeological studies of Latin American Indians).



E.             Order of subject headings :  The general principle is to assign headings in order of the importance of the subject in the work.  Thus, the first heading should reflect the most central topic of the work.  The order is not always straightforward, however, when a cluster of headings is needed to bring out one topic (cf. I.D.2 above).


Please note that the MARC tag number for the type of subject heading is not a factor in assigning the order of headings.

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Forms and construction

Basic (main) heading Subdivisions


In checking a subject heading, you naturally need to confirm that its meaning is appropriate for the content of the work.  In addition, if verification of the heading is required, you need to be sure that it is valid in its construction and application according to LCSH rules.  This section deals with valid construction.


A. Basic (main) heading

Topical Uniform title
Name Geographic


1.             Topical  (MARC tag 650):  May represent:  a concrete object, animal, etc.; a category of people, animals, or objects; a more abstract concept, belief, process, or phenomenon; an institution, etc.


A topical heading may be a term consisting of a single word or a phrase.


a.             Single word:  probably the most common form.


E.g.                         Housing




b.             Phrase:  Various methods of constructing a topical phrase heading include:


1)             Direct order


E.g.         Housing policy

Foreign exchange administration


2)             Inverted order; inverted headings include a comma.  In theory, the more significant term is given first, then followed by a modifier.  An inverted topical heading functions almost like a hierarchy, although it is not formally structured as such through MARC coding, since a phrase is used rather than a coded subdivision.


E.g.         Authors, Mexican

Farms, Small 


3)             Term plus qualifying term; the qualifier is in parentheses and should resolve ambiguities or make the context of the term clearer.


E.g.         Stress (Physiology)

Stress (Psychology


Consumption (Economics)                 [i.e., not tuberculosis, not energy or food consumption ]


4)             A topical phrase heading may include prepositions.


E.g.         Violence in motion pictures

Children of alcoholics


5)             A topical phrase heading may include related terms connected with "and." 


E.g.         Banks and banking

Cities and towns


6)             Occasionally, a phrase consists of list of terms seen as related, with 2 terms plus "etc."


E.g.         Comic books, strips, etc.


E.g.         Survival after airplane accidents, shipwrecks, etc.


7)             Combination or modification of above.


E.g.         Banks and banking, Central [compound direct, plus

inverted addition]


Registers of births, etc. (Canon law)  [preposition, one phrase, plus

"etc."; followed by parenthetical qualifier]


Creative ability in science


2.             Name -- personal, corporate, or conference  (MARC tag 600, 610, or 611):  The form of a name heading used as a subject should be the same as that in the name authority file, so the form of an access point is the same whether its function in the record is to represent an author, responsible body, or subject.  Therefore, the rules for construction are covered in AACR2 revised (chapters 22 and 24) and the associated LCRI.  (This authority work will be covered later.)


3.             Uniform title  (MARC tag 630):  The form of a uniform title heading used as a subject should be the same as that in the name authority file, so the form of the access point is the same whether its function in the record is to represent the uniform title for the content of a work, for the content of part of a work, for a series, or for the subject (a work discussed in the work in hand).  Therefore, the rules for construction are covered in AACR2 revised (chapter 25) and the associated LCRI.  (This authority work will be covered later.)


4.             Geographic  (MARC tag 651):  There are two categories, with various complicating factors:


a.             Places that have or had jurisdictional status on some level:  Such places -- e.g., countries, cities, and provinces -- have governments that could issue works and thus could function as corporate authors.


E.g.         Argentina

Buenos Aires (Argentina)


Jefferson Parish (La.)

North Yorkshire (England)


LC might set up a jurisdiction in its name authority file or its subject authority file -- depending on the situation and, historically, who got to it first.  The form of access point should be the same whether its function in the record is to represent a responsible body or subject.  The rules for construction are covered in AACR2 revised (chapter 23) and the associated LCRI.  Additional relevant rules show up in the Subject Cataloging Manual: Subject Headings. 


b.             Geographic features without jurisdictional status:  Such places -- e.g., individual mountains or mountain ranges, rivers, bays; regions larger than countries, including continents and groups of countries; regions within countries that do not correspond to political divisions -- could only relate to a work as subjects.  


E.g.         Alps

Olympus, Mount (Greece)

Mississippi River


West Indies

Atlantic Coast (Nicaragua)


LC sets up subject authority records for headings for geographic features.  Guidelines are provided in the Subject Cataloging Manual: Subject Headings.


For additional information about geographic headings, see “Introduction to Geographic Headings.”


B.            Subject heading strings:  Subdivisions


If a subject heading consists of a string, with a heading and one or more subdivisions, and verification is required, you need to be sure that the string is constructed correctly:


1.             Valid


a.             Valid to use that subdivision under that heading or type of heading.


E.g.         Farms, Small $z Colombia:  You need to verify that the topical heading "Farms, Small" may be subdivided geographically (with a $z subfield or pair of $z subfields for the place).


Camus, Albert, $d 1913-1960 $v Congresses:  You need to verify that the form subdivision "Congresses" may be used under names of persons.


b.             Subdivision is in the correct form. 


Please note:  The function and construction of a subdivision is not the same as that of a subject heading.  Therefore, the valid form of a subdivision will not necessarily be the same as that of a subject heading with a similar meaning.


E.g.         650  0  Economic history.


                651  0  Chile $x Economic conditions.


Subdivisions with similar meanings may also be different under different types of headings.


E.g.         650  0  Children $x Religious life.        [under classes of persons]


                651  0  Ethiopia $x Religious life and customs.                [under places]


2.             In the correct order when more than one subdivision is present.


E.g.                         650  0  Women $z Italy $x Social conditions.


650  0  Women $x Employment $z Italy.


(For more information about subject subdvisions, see "Some Common Library of Congress Subject Subdivision Patterns and Caveats.")

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LCSH:  Some limitations and caveats


A.            The list of LC subject headings is not comprehensive:  It is based on "literary warrant" -- i.e., based on headings that have actually been used to reflect topics in works catalogued at LC or at libraries where SACO proposals for new subject headings have been submitted, then accepted at LC.  You may continually run up against the problem of not finding a heading for a major topic that the work covers.  (Our trained original cataloguers sometimes submit SACO proposals for new subjects.)


B.            The choice and form of headings are not necessarily current:  The LCSH terms have evolved over time, but they can never be totally up to date.   Although LC has made considerable efforts to keep up to date in its subject terminology, you will still find terms that sound archaic or that diverge from common terms (e.g., the subdivision "$x Antiquities").  Currently, weekly lists with updated, new, or deleted terms are issued; quarterly lists are printed in issues of the LC Cataloging Service Bulletin (CSBs) with new headings that LC thinks may be particularly timely. 


E.g.         650  0  Man                           

is now obsolete; switched (in Winter 1997) to

Human beings


E.g.         recent heading (Fall 2002):  650  0  Marine ecotourism

E.g.         recent heading (January 2007):  650  0  Asian American women in motion pictures


C.            The meaning and usage of a term in LCSH may not be what we might expect from its use in regular spoken English.  You sometimes need to consult scope notes and/or bib records to figure out what the term really means in LCSH.


E.g.         650  0  Archaeology $z Mexico --   refers to the discipline of archaeology, Mexican archaeologists,



651  0  Mexico $x Antiquities -- refers to archaeological sites, artefacts, etc.


D.            The form of a subject heading or subject string is not always easy to predict.  Plans are in the process of being implemented to update and simplify patterns of subject heading construction.  For example, more phrase headings now appear in direct rather than inverted order.


E.g.         Women, Deaf

is now obsolete; switched to:                                            650  0  Deaf women


E.g.         Societies, Primitive

is now obsolete; switched to:                                            650  0  Primitive societies

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Verifying LCSH

Different sources have different advantages and limitations when searching topical, genre, and geographic headings.  One may be more appropriate than the other, depending on the type of heading or subdivision that needs to be verified.

Online LC/SACO subject authority file: Printed LC subject authority file
      in OCLC Connexion Subject Cataloging Manual: Subject Headings
      in Voyager

A.            Online LC/SACO Subject Authority File

1.         in OCLC Connexion

a.             Advantages:

1)             Most current and authoritative.

2)             Includes records for freefloating subdivisions.

3)            Available on your desktop.

4)             Now fairly easy to search.

5)             If you do original cataloging online, the authority files in OCLC are right in the same place.

b.             Limitations:

1)             You need to learn and remember some searching quirks: 

--             Derived search key: 

--             5,3 for 151 topical headings and 781 geographic subdivisions

               E.g.      artis,col    for Artist colonies

               E.g.      greec,ath    for Athens (Greece) via 781 $z Greece $z Athens

--             Subdivisions can be included

               E.g.      art,col    for Art $x Collectors and collecting


--             “Scan” searches:


                --             sca su: -- for 150 topical and 151 geographic headings, 180 topical subdivisions, and 185 form subdivisions

                --             sca gg: -- for 151 geographic headings only

                --             Browse search based on beginning word or phrase

                --             Punctuation (parentheses and commas) can be omitted

--             Initial search cannot include subdivisions; to add subdivision, highlight main heading and key in all or part of subdivision in "Expanded term" box


--             Keyword searches:


                --             su: -- for 150 topical and 151 geographic headings, 180 topical subdivisions, and 185 form subdivisions

                --             gg: -- for 151 geographic headings and $z geographic subdivisions only

                --             Keyword search, with optional truncation, for matching character string anywhere in heading or reference

               E.g.      gg:wetland?    retrieves records including 151 Nakivubo Urban Wetland (Uganda), 151 Ballona Wetlands (Calif.), 451 Sedgemoor (England : Wetlands), etc.

                --             Punctuation (parentheses and commas) can be omitted

--             Initial search cannot include subdivisions; heading strings including subdivisions display in list of hits

--             May result in response:  "Too many records found for your search"

2)             A subject authority record may have scope notes and clues to usage, but it may not; the same search does not pull up bib records that could help clarify the meaning and application of a subject heading.

2.             in Voyager -– through Staff Subject Headings Search

a.             Advantages:

1)             Available on your desktop.

2)             Quite easy to search, few quirks to learn, e.g.:


--             All types of subject headings are grouped together regardless of tag

--             Punctuation can be ignored

--             Subdivisions can be included

3)             Using the same search, bib records are usually also retrieved, which can be compared for examples of the actual use of the heading.

4)             Subject authority records in Voyager occasionally include local modifications, such as clarifications, additional cross-references, and so forth.

b.             Limitations:


1)             Not necessarily current.  Most subject authority records were loaded into our local authority file in January 1991, and many have not been checked or updated since then.


2)             Not as comprehensive as the LC/SACO Subject Authority File:  It only includes records for headings that we have actually already used in bib records (with a few exceptions), and there are often no authority records for subject headings first used in our bib records after January 1991.

3)             Of limited use for searching subdivisions – authority records are usually only available in our local file for non-free-floating subdivisions; information about a free-floating subdivision may be located within an entry for a comparable heading (which may not have the same format and thus may need to be searched differently).

4)             Keyword searching of authority records is not available in Voyager.


B.            Printed LC Subject Authority File -- "Red books"

1.             Advantages:

a.             Includes introductory, explanatory information.

b.             Some people find it easier to read:  quicker to scan and easier on the eyes.

2.             Limitations:

a.             Out of date almost as soon as it is printed.  (29th ed.:  2006)

b.             Not available at your desk.

c.             Of limited use for searching subdivisions -- only non-free-floating ones are included, or information about free-floating subdivisions within an entry for a comparable heading (which may not have the same format and thus may need to be searched differently).

C.            Subject Cataloging Manual:  Subject Headings  (SCM:SH)

Consulting the Subject Cataloging Manual: Subject Headings – on Cataloger’s Desktop or in print form – is most appropriate for: 

1.             General introductory information about subject headings and their assignment.

2.             Free-floating subdivisions:  lists, with numerous scope notes. 

3.             Geographic headings and subdivisions:  information on their construction.

4.             Guidelines on headings and subdivisions covering particular topics; certain specific headings and subdivisions.  (Not comprehensive)

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draft 21 February 1996; rev. draft 12 March 1996, 9 July 1997, 16 December 2002, 8 March 2003, 18 August 2006, 3 May 2007

HTML document last reviewed:  7 May 2007