H 180 Assigning and Constructing Subject
Headings
BACKGROUND: This
instruction sheet contains general practices followed by the Library of
Congress for assigning subject headings to individual works being cataloged and
for constructing subject heading strings in the Library of Congress subject
heading system. This instruction sheet
begins after the initial steps of subject analysis have taken place, that is,
after an examination of the item to determine its subject focus and an
identification of how that basic subject is expressed with the controlled
vocabulary of the Library of Congress subject heading system.
1. General rule. Assign to the work being cataloged one or more subject headings that best summarize the overall contents of the work and provide access to its most important topics.
LC practice:
Assign headings only for topics that comprise at least 20%
of the work.
In the case of a work containing separate parts, for
example, a narrative text plus an extensive bibliography or a section of maps
(cf. H 1865), or a book with accompanying materials, such as a computer disc,
assign separate headings for the individual parts or materials if they
constitute at least 20% of the item and are judged to be significant.
Note: There are
certain works to which the Library of Congress assigns no subject headings
because of their very general or amorphous nature, for example, a general
periodical or a collection of essays with no discernable theme. In addition, it is Library of Congress
practice not to assign subject headings to texts of sacred works or to
individual works of belles lettres with no
identifiable theme or specific form (cf. H 1775 sec. 3.c.).
2. Cataloging
treatment. Assign subject headings that
correspond to the cataloging treatment of the work. For example, to a record that represents a
collected set, such as a periodical, monographic series, or multi-part item,
assign headings that characterize the general contents of the set as a whole.
To a record that represents an analytic in a collected set,
assign headings that represent the specific contents of the analytic item.
To a work that contains both text and commentary,
assign headings to represent either the text or the commentary depending upon
the descriptive treatment of the item (cf. H 1435).
Assign headings based on an analysis of the contents of the
work being cataloged. Subject headings
do not need to be justified by descriptive cataloging notes.
3. Number of
headings. The number of headings that
are required varies with the work being cataloged. Sometimes one heading is sufficient. Generally a maximum of six is
appropriate. In special situations more
headings may be required.
LC practice:
Do not assign more than ten headings to a work.
Note: As many as ten
Annotated Card Program (AC) headings may be assigned to a juvenile work in
addition to the assigned Library of Congress subject headings.
If more than one heading is present, Library of Congress
catalogers assign them in order of predominance. See H 80 for instructions on order of
headings.
4. Specificity. Assign headings that are as specific as the
topics they cover. Specificity is not a
property of a given subject heading; instead, it is a relative concept that
reflects the relationship between a subject heading and the work to which it is
applied. For example, a seemingly broad
heading like Psychology is specific when it is assigned to an introductory
textbook on psychology. The method
through which specificity is achieved depends on the nature of the available
headings. In many cases, specificity can
be achieved by assigning a basic heading consisting of one word or a phrase; in
other cases, specificity can be achieved by subdividing a heading. See sec. 15 below for a discussion of the
construction of subject headings.
Follow the hierarchical reference structure built into the
subject authority file (cf. H 370) to find as close a match as possible between
the topic of the work and the headings that exist to express that topic in the
Library of Congress subject heading system.
In situations where a needed heading is neither established in the
subject authority file nor able to be constructed using free-floating elements,
see H 187 for general guidelines on establishing new subject headings.
Assign a heading that is broader or more general than the
topic that it is intended to cover only when it is not possible to establish a
precise heading, when an array of headings is needed to express the topic, or
when the assignment of a more general heading is called for by special
instructions in the Subject Headings Manual.
For example, H 1334 and H 1334.5 contain instructions to add a heading
of the type [city]–Buildings, structures, etc. to works that discuss an
individual named building or a category of buildings in a city from the
architectural standpoint.
5. Depth of
indexing. A given heading, depending
upon its place in a hierarchy, may subsume several subtopics that are also represented
by headings in the subject authority file.
Assign to a work only the headings that most closely correspond to the
overall coverage of the work. Do not
assign headings that represent the subtopics normally considered to be included
in an assigned heading's coverage.
Example:
Title: Beginning
gymnastics.
650 #0 $a Gymnastics.
[Do not assign separate headings for parallel bars, balance
beam, horizontal beam, vaulting horse, tumbling, etc., instead of, or in
addition to, Gymnastics.]
6. General topic and
subtopic; principle vs. specific case.
If a work discusses a general topic with emphasis on a particular
subtopic, or presents a principle and illustrates the principle with a specific
case or example, assign headings for both the general topic or principle and
for the subtopic or specific case or example, provided that the treatment of
the latter forms at least 20% of the work.
Example:
Title: Revolutions
yesterday and today.
[A survey of revolutions with emphasis on the Cuban
Revolution of 1959]
650 #0 $a Revolutions $x History.
651 #0 $a
7. Two or three
related headings. If a heading exists,
or can be established, that represents the two or three topics discussed in a
work, and that includes no other topics within its scope, assign the one
heading instead of two or three narrower headings.
Examples:
Title: By land, sea,
and air : the story of transportation.
650 #0 $a Transportation $x History.
Title: In praise of
single parents : mothers and fathers embracing the
challenge.
650 #0 $a Single parents $z
[not
650 #0 $a Single mothers $z
650 #0 $a Single fathers $z
8. Rule of
three. If a general topic includes in
its scope more than three subtopics, but the work being cataloged discusses
only two or three of these subtopics, assign the appropriate two or three
headings rather than the broader heading.
Example:
Title:
650 #0 $a Peach $z
650 #0 $a Apples $z
If more than three of the subtopics are discussed in the
work, assign the broad heading instead, unless the rule of four, described
below, applies.
9. Rule of four. In certain circumstances it may be preferable
to assign headings for four subtopics of a broad concept. If a heading covers a broad range and each
subtopic forms only a small portion of that whole range, assign the four
subtopics instead. For example, for a
discussion of the works of four American literary authors, a heading for each
author may be assigned since the heading American literature–History and
criticism covers the works of all American authors.
LC practice:
Do not exceed four subtopics under any circumstances.
10. Multi-element
topics. If a work discusses a complex or
compound topic for which a single heading neither exists nor can be practically
constructed or established, assign multiple headings to bring out the separate
aspects of the topic.
Example:
Title: Cancer
morbidity and mortality among Danish brewery workers.
650 #0 $a Cancer $z
650 #0 $a Cancer $x Mortality $z
650 #0 $a Brewery workers $x Diseases $z
650 #0 $a Brewery workers $x Mortality $z
In some cases, patterns in the subject authority file call
for assigning a combination of headings that together are coextensive with the
topic.
Example:
Title: Lipid
metabolism in ruminant animals.
650 #0 $a Ruminants $x Metabolism.
650 #0 $a Lipids $x Metabolism.
11. Additional
aspects. In the headings assigned to a
work, bring out important additional aspects, such as limitation to a specific
place or time, focus on specific named entities, and presentation in a
particular form. These aspects may be
expressed by means of headings themselves, adjectival qualifiers in headings,
or subdivisions. See sec. 16 below for a
discussion of complete subject heading strings with subdivisions.
a. Place.
Geographic features and jurisdictions can play a key role in the contents
of a work in terms of location, setting, derivation, or origin, and need to be
reflected in the assigned headings. See
H 690 - H 910 for instruction sheets on geographic headings and subdivisions,
and H 320 and H 350 for guidelines on national adjectival qualifiers in subject
headings.
b. Time.
Express the chronological aspects significant to the contents of the
work in situations where the Library of Congress subject heading system allows
it. See H 620 for a discussion of
chronological headings and subdivisions.
c. Named entities. Assign headings from either the name
authority file or subject authority file for individual persons, families,
corporate bodies, projects, events, buildings, named products, uniform titles,
etc., that are significant to the contents of the work. Assign headings of this type when these named
entities are critical to the subject of the work as a whole, even if discussion
of them does not form 20% of the work.
See H 430 for instructions on assigning name headings as subjects and H
405 for a discussion of which file to consult to find authority records for
ambiguous named entities.
d. Form.
Assign form headings and subdivisions to represent what the item itself
is, that is, its format or the particular type or arrangement of data that it
contains, in situations where headings or subdivisions for these types of
materials exist, and it is Library of Congress practice to designate them. Consult the instruction sheets for particular
types of materials in the Subject Headings Manual, for example, dictionaries (H
1540); genealogy (H 1631); illustrations (H 1659); juvenile materials (H 1690);
software (H 2070); treaties (H 2227).
12. Concepts in
titles. Titles and subtitles are
important because they sometimes state in the words of the author or publisher
the subject matter of the work. Bring
out or account for each topic of subject retrieval value that is identified in
the title or subtitle and discussed in the work. Apply judgment and consider the following
points when applying this principle:
·
If the title is misleading, euphemistic, or cryptic, do not use the
title as a guide to the contents of the work.
·
If the topic is one that as a matter of policy is not expressed in
subject headings, , do not bring out this aspect in
the assigned subject headings. For
example, do not assign specific headings to reflect a narrow time period in the
history of a village. Instead, apply a
general free-floating century subdivision (cf. H 620, sec. 3.d.(1)).
·
If the title is general but the work is actually on a more specific
topic, assign heading(s) for the specific topic.
·
If many topics are listed on the title page in the manner of a table of
contents, treat them as a table of contents.
13. Additional
headings. Because of the complex nature
of certain topics, or special practices that have been developed for particular
topics, additional headings may be required.
Consult the appropriate instruction sheets in the Subject Headings
Manual or scope notes in the subject authority file for guidance on handling
these situations. For example, special
provisions exist for works on foreign relations (H 1629); folklore (H 1627);
public opinion (H 1955); biography (H 1330); local history and genealogical
source materials (H 1845); and other special topics.
14. Objectivity. Avoid assigning headings that label topics or
express personal value judgments regarding topics or materials. Individual cataloger knowledge and judgment
inevitably play a role in assessing what is significant in a work's contents,
but headings should not be assigned that reflect a cataloger's opinion about
the contents. Consider the intent of the
author or publisher and, if possible, assign headings for this orientation
without being judgmental. Follow stated
intentions of the author or publisher in such matters as readership, audience
level, treatment as fact or fiction, etc.
15. Constructing headings.
Subject headings may be in the form of a word, a phrase, or a name, all
assigned with or without subdivisions.
Examples:
· Simple nouns: Children; Dogs; Libraries
· Compound
nouns: Bioengineering; Electrometallurgy
· Nouns with
parenthetical qualifiers: Seals
(Animals); Crack (Drug)
· Nouns with
adjectives: Gifted children; Wild dogs;
Academic libraries;
Sculpture, American; Science, Ancient
· Phrases with
prepositions: Teachers of gifted
children; Photography of dogs; Photocopying services
in libraries
· Compound
phrases: Children and animals; Bolts and
nuts; Comic strips, books, etc.
· Complex
phrases: Names carved on trees; Infants
switched at birth; Monkeys as aids for people with disabilities
· Topical, name, or
form/genre headings with subdivisions:
Taxation–Effect of inflation on;
There is no general rule for correlating elements of
compound topics when establishing precoordinated
headings. New headings are usually
formulated following precedents and patterns that exist in a particular
discipline or field of knowledge. See H
290-H 360 for instructions on formulating headings of certain types. Whenever it is feasible, consistency in form
and structure among similar headings is achieved through the use of recurring
patterns. For example, see H 1580 and H
1675 for instructions involving headings for effect and influence of one topic
on another.
16. Complete subject heading strings with subdivisions. Each subject heading assigned to a work should be in the form of a complete string composed of a number of prescribed elements of which headings established in the subject authority file represent only a part. In many cases, it is not sufficient to select an individual heading or heading-subdivision combination from the subject authority file. As appropriate, supply additional elements to represent subtopic, place, time, and form in accordance with instructions in the subject authority file and the Subject Headings Manual. Consult H 1075 for general instructions on subdivisions, including the four types of subdivisions and the prescribed orders for combining them in meaningful subject heading strings. Assign subdivisions to reflect the contents of the work without regard to the size of the file under the basic heading.