H 1075 Subdivisions
BACKGROUND: Subdivisions are essential elements in the Library of Congress subject heading system. They are extensively used to combine various aspects of a topic into one heading and to arrange entries that share the same main heading in a file. This instruction sheet outlines the four types of subdivisions and the two basic orders that are used to combine subdivisions in complete and meaningful subject heading strings. For instructions on those subdivisions whose use is authorized by general instructions in the Subject Cataloging Manual and in the subject authority file, see H 1095.
1. Types of subdivisions.
There are four types of subdivisions: topical, geographic, chronological, and form.
a. Topical subdivisions. Topical subdivisions are used under headings of all types to limit the concept expressed by the heading to a subtopic. Many common topical subdivisions represent actions, attributes, or aspects, for example, Helicopters-Flight testing; Drinking water-Aluminum content; Mental health-Nutritional aspects. Topical subdivisions are used as a standard way of expressing concepts, methods, or techniques that are common to several fields, or that may be applied to numerous headings, for example, -Psychological aspects; -Research; -Statistical methods. Subdivisions are generally preferred over phrase headings for subtopics or aspects that may repeatedly appear in association with a variety of topics or entities. In some cases, particularly with headings for objects, subdivisions are used to designate parts of the whole represented by the main heading, for example, Ships-Radio antennas or Fishes-Nervous system. When more than one topical subdivision is used with a main heading, each subdivision refines the concept expressed by the heading and makes it more specific, for example, Construction industry-Management; Construction industry-Management-Employee participation. Topical subdivisions appear in $x subfields in MARC 21.
b. Geographic subdivisions. Geographic subdivisions indicate the geographic area to which treatment of a topic is limited. They may designate where something is located, or where something is from, depending upon the topic. When a heading is authorized for geographic subdivision, it may be subdivided by place. See H 364 for guidelines on coding authority records to authorize geographic subdivision for headings. See H 830 for instructions on assigning authorized headings with geographic subdivisions. Geographic subdivisions appear in $z subfields in MARC 21.
c. Chronological subdivisions. Chronological or period subdivisions indicate time periods covered in the contents of the work. They are usually associated with a historical treatment of a topic and are established or used under topics after the subdivision -History, for example, Women-History-To 500. With topics and topical subdivisions that the Library of Congress treats as inherently historical (cf. H 1647, sec. 4), chronological subdivisions are established without interposing the subdivision -History, for example, Russia-Social conditions-1801-1917. Chronological subdivisions that are established or used under artistic, literary, or music form/genre headings modify the main heading and represent artistic, literary, or musical compositions or works created in that time period, for example, Engraving-18th century; French poetry-19th century; Sonatas (Piano)-20th century. Consult H 620 for further information on chronological subdivisions. Chronological subdivisions appear in $y subfields in MARC 21.
d. Form subdivisions. Form subdivisions indicate what the item is rather than what it is about. The most frequently used form subdivisions, such as -Bibliography, -Juvenile literature, and -Periodicals, may be used with all types of main headings and other subdivisions. Most form subdivisions may also be used as topical subdivisions for works about those specific forms. For example, the heading Medicine-Periodicals is assigned to a general medical periodical; the heading Medicine-Periodicals-History is assigned to a monograph on the history of medical periodicals. Generally, a form subdivision is the final element in a heading, for example, Nuclear reactors-Design and construction-Software. Occasionally, two subdivisions are needed to indicate form, for example, Technology-Bibliography-Periodicals (for a bibliography that is issued as a periodical). Include a form subdivision in a subject heading string when the appropriate form subdivision exists and it is Library of Congress practice to designate that form. As a general rule, include the same form subdivision in all headings assigned to the work unless (1) the form subdivision is not authorized for use under a particular type of heading (cf. H 1927 for periodicals), or (2) the form represents only a part of the work and separate headings are being assigned for that portion of the work. Until 1999, form subdivisions were coded as $x subfields, the same subfield code used for topical subdivisions. In February 1999, the Library of Congress began to apply the new subfield code approved in MARC 21 to distinguish form subdivisions, the $v subfield, to newly cataloged materials. After that date, code a form subdivision for the function that the subdivision performs in the subject heading string. Code a form subdivision as a $v subfield when it represents what the item being cataloged is.
Title: Investors guide to stock quotations.
650 #0 $a Stock quotations $v Handbooks, manuals etc.
Title: Words you need to know to pass admissions & standardized tests.
650 #0 $a Vocabulary tests $v Study guides.
650 #0 $a Vocabulary $v Problems, exercises, etc.
Code a form subdivision as an $x subfield when it represents a form that the item is about. This often occurs when a subdivision that is normally a form subdivision is immediately followed by another form subdivision, or by a topical subdivision.
Title: Metals handbook comprehensive index.
630 00 $a Metals handbook $v Indexes.
650 #0 $a Metals $x Handbooks, manuals, etc. $v Indexes.
[In the second heading in this example, -Handbooks, manuals, etc., which is normally a form subdivision, is coded as an $x subfield, because the work itself is not a handbook, but is an index to handbooks.]
Title: A bibliography of test study materials.
650 #0 $a Examinations $x Study guides $v Bibliography.
[In this example, -Study guides, which is normally a form subdivision, is coded as an $x subfield because the work itself is not a study guide, but is a bibliography of study guides.]
2. Order of subdivisions.
There are two basic orders for combining headings with subdivisions to form subject heading strings: [place]-[topic] and [topic]-[place].
a. [Place]-[topic] headings. This order is generally used for aspects of a place, for example, its history, politics, economics, civilization, intellectual life, or social history and conditions. The free-floating form and topical subdivisions used under places are listed in H 1140 for regions, countries, etc., and H 1145.5 for bodies of water. The order of a subject heading string of this type that includes all types of subdivisions is usually:
651 #0 $a [place] $x [topic] $y [chronological period] $v [form].
Minor variations are possible when additional topical or place elements are present, or when more than one form subdivision is required in a single heading.
651 #0 $a United States $x Social conditions $y 1980- $x Juvenile literature $v Bibliography.
651 #0 $a Great Britain $x Kings and rulers $x Travel $z Canada $v Pictorial works $v Juvenile literature.
b. [Topic]-[place] headings. This order is used for topical headings that are authorized for geographic subdivision. The order of a subject heading string of this type that includes all types of subdivisions is usually one of the following depending on whether the topical subdivision is authorized for further subdivision by place (cf. H 860).
650 #0 $a [topic] $z [place] $x [topic] $y [chronological period] $v [form].
650 #0 $a [topic] $x [topic] $z [place] $y [chronological period] $v [form].
Minor variations are possible when additional topical elements are present, or when more than one form subdivision is required in a single heading.
650 #0 $a Railroads $z France $x Cars $x History $y 19th century $v Pictorial works $v Juvenile literature.
650 #0 $a Tuberculosis $x Patients $x Hospital care $z Maryland $z Baltimore $x History $y 20th century $v Bibliography.
650 #0 $a Church and state $z France $x History $y 19th century $x Periodicals $v Bibliography.
3. Order of subdivisions and meaning of subject heading strings.
Generally, use established headings and follow instructions for combining them with free-floating subdivisions, placing form subdivisions last. Follow a logical thought process to express the topic that most closely corresponds to the contents of the work being cataloged. The meaning of a subject heading string may be tested by constructing a phrase using the individual elements of the subject heading string in reverse order. Examples:
650 #0 $a Authors, English $y 20th century $v Biography.
[A biography of 20th century English authors]
651 #0 $a United States $x Foreign relations $y 1783-1815 $x Sources $v Bibliography.
[A bibliography of sources for foreign relations of the
650 #0 $a German literature $x History and criticism $v Periodicals.
[A periodical on the history and criticism of German literature]
The same elements may express different concepts depending upon their order in a subject heading string. Examples:
650 #0 $a Hospitals $x Administration $x Data processing $x Evaluation.
[Evaluation of the application of data processing to the administration of hospitals]
650 #0 $a Hospitals $x Administration $x Evaluation $x Data processing.
[Application of data processing to the evaluation of the administration of hospitals]
650 #0 $a Science $x History $v Periodicals.
[A periodical on the history of science]
650 #0 $a Science $x Periodicals $x History.
[A history of periodicals in the field of science]