MeSH & Principles of
Classification
April 13, 2005
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Medical Subject Headings
(MeSH)
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Thesaurus developed in the 1960s for
online use
More detailed than LCSH for medical
terminology
Pre-coordinated but not to same extent
as LCSH
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Vocabulary
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Same vocabulary is used for cataloging
books and for indexing journals
19,000 main subject headings
82 topical subheadings or qualifiers
Each subject heading and qualifier has
a scope note and the categories under
which it may be used
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Vocabulary (cont.)
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Does not include form, geographic or
language subheadings
Does use publication types as headings
Kinds of study, types of study, and
sources of support are specified (“check
tags”)
Can limit searching by language, type,
medium, location, etc.
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Descriptors for:
Cutaneous adverse events in renal transplant recipients receiving
sirolimus-based therapy (journal article)
Adult
Aged
Cross-sectional studies
Edema/etiology
Female
Hair/pathology
Humans
Immunosuppressive
agents/*adverse
effects
*Kidney transplantation
Male
Middle aged
Mucous
membrane/pathology
Nails/pathology
Sebaceous
glands/pathology
Sirolimus/*adverse
effects
Skin
diseases/*chemically
induced
Skin diseases,
Infectious/etiology
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Syntax
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Some subject headings are inverted
Subject headings may be subdivided,
but no more than two elements are
permitted
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If more than one qualifier is needed, then
the subject heading is repeated. Example:
Coronary disease / ep [Epidemiology]
Coronary disease / me [Metabolism]
*Coronary disease / pc [Prevention & Control]
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MeSH Thesaurus
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Available in three forms online and/or in
print:
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Tree structure
Alphabetic list
Annotated Alphabetic List
PubMed
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Alphabetic List
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1st section:
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every subject heading and subdivision in
one alphabetical list regardless of hierarchy
notational equivalent(s)
History of the term, including year of
adoption, earlier terms
Cross-references
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Alphabetic List (cont.)
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2nd section:
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Categories and subcategories
Records subcategories in alphabetical order
with their notations
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Annotated Alphabetic List
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Only in print form
Designed for catalogers, indexers, and
online searchers
Contains scope notes, check tags, and
other information not included in the
Alphabetic List
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Principles of Classification
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Definitions
Uses of classification
Components of classification systems
“Characteristic of division”
Enumerative vs. synthetic schemes
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Definitions
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Classification: The systematic arrangement
of objects or concepts in groups or classes
according to their similarities and differences
or their relation to a set of criteria. (Olson &
Boll, 2001)
In bibliographic classification, like
subjects are grouped together and related
subjects are near one another
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Definitions (cont.)
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Class numbers or classification
numbers -- symbols used to identify
classes (preferably called notation
since they can be alphabetic or
alphanumeric)
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Classification scheme
characteristics
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Dynamic
Book numbers (a.k.a. Cutter
numbers) allow for subarrangement of
books within a class
Principles of subarrangement within
classes achieved with shelflisting
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Uses of Classification
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Arrangement of materials on shelves
Arrangement of document surrogates in
paper catalogs
Online manipulation of document
surrogates (online shelf list) for online
browsing
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Importance of Browsing
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Ranganathan’s principle: Save the time of the
user
In open stack libraries, browsing is a
significant method of resource discovery
In OPACs which include remote resources,
the ability of users to browse an online
shelflist increases the likelihood of discovering
those remote resources. There is no other
way at present to browse remote resources.
The library’s efforts to fully classify a
collection results in time savings for users and
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staff.
Components of a Classification
Scheme
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verbal description of things and concepts
arrangement into a classed/logical order
that is meaningful and convenient
notation alongside each verbal description;
together these form schedules
references to guide user to other aspects of
topics or related topics
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Components of a Classification
Scheme (cont.)
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alphabetical index of terms used in the
schedules with synonyms
instructions for use
mechanisms for revision
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Characteristic of division
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Groups of abstract concepts, objects, or
activities are divided into smaller groups
The criterion for division is called the
“characteristic of division”
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Types of Characteristics of
Division (cont.)
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Genus to species (or group to member)
Primates to Apes
Whole to parts
Nervous system to Spinal cord
Continuous process
Textiles, Carding, Spinning, Weaving,
Finishing
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Types of Characteristics of
Division (cont.)
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Increasing complexity
Music for duets, for trios, for quartets
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Chronological (history of a country)
Czechoslovakia, 1918-1939, 1939-1945,
1945-1968
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Spatial: Continent to Country
Europe to Czech Republic
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Characteristics of Division
(cont.)
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Division continues until no other
divisions can be made
Creates a hierarchy
Overlapping hierarchies may exist as
there may be more than one way of
dividing a topic
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Enumerative Classification
Schemes
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Every topic that can be classified is
enumerated in the scheme
Topics not enumerated separately must
be classed with a broader topic
Narrow compound topics can be
accomodated by narrowing the class
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Linearity
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Linearity: documents can only be
shelved by one characteristic
Only major aspects of a work are
considered in classification
Compound topics present a problem
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Solutions to compound topics
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Rules:
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Classify by emphasis of the work
Classify by one criterion when two apply
Classify by the first class in the schedules
These rules can be arbitrary and are of
no use to browsers
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Synthetic Classification
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Combine notations for different
concepts to create compound notations
Faceted classification is one type of
synthetic classification
Ranganathan’s colon classification – five
facets
Read more about it in Chapter 7, SAOC!
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