Making Visible Hidden Relationships in the Dewey Decimal Classification:

How Relative Index Terms Relate to DDC Classes

10th International ISKO Conference

August 6, 2008

Rebecca GreenAssistant Editor

Dewey Decimal Classification

Example class

796.86 Fencing Including bojutsu, kendo Class here sword fighting

RI: BojutsuFencing (Swordplay)KendoSword fightingSwordplay

DDC classes

Class as gathering point for set of topicsCaptionIncluding conceptsClass here concepts

Topics either equal / approximate whole of class or are in standing room in class

Topics in classes

Approximating the whole vs. standing room:Standard subdivisions can only be added for topics that approximate the whole of the class, not for those in standing roomFuture expansion anticipated for topics in standing room, not for those that approximate the wholeTopics in class-here notes approximate the whole of the class; topics in including notes are in standing room

Relative Index terms and class topics

Explicitly: Relative Index terms index class as whole

Implicitly: Relative Index terms associated with specific topics in classSpecific associations not recordedThus, unknown if Relative Index term topic approximates the whole of the class or is in standing room there

Project attempts to make this designation automatically

Motivation

Correct decision on addition of standard subdivisions

Maintenance of scheme: If topic moves to another class, associated Relative Index term should, too

Support automated operations on scheme, e.g., creation of derived versions

Difficulties

Identification of topics

Topics in captionIn multitopic caption, topics may approximate whole or be in standing room

Paraphrase relationship between topics in schedules and Relative Index terms (morphological, syntactic, semantic)

Example

133.3 Divinatory arts Including fortune-telling by

bones, dice, pendulumRelative Index terms:

Bones—divinationDice—divinationPendulums—divination

Standard subdivisions note

749 Furniture and accessoriesStandard subdivisions are added for furniture and accessories together, for furniture alone

Two-phase approach

In schedulesIsolate topicsDetermine if topics equal / approximate whole of

class (AW) or are in standing room (SR)

Match Relative Index terms to schedule topics, using series of increasingly more relaxed strategies

Topic isolation

Sign languages used primarily for purposes other than communication of deaf people

Systems programs Operating systemsSatellites and rings; eclipses, transits,

occultationsReligious experience, life, practice [can’t

parse reliably]

Approximates-the-whole topics

All topics in class-here note

Topic in single topic caption

Topic in multitopic caption, with note that standard subdivisions are added for:

Any or all topics in headingEither or both topics in headingThe specific topic alone

Standing room topics

All topics in including notes

Topic in multitopic caption, with note for adding standard subdivisions, not meeting criteria for approximating the whole

Topic in multitopic caption, without note for adding standard subdivisions, that matches topic in subordinate caption

Matching RI terms to topics:EXACT match

121 Epistemology (Theory of knowledge)

121.63      Certainty and probabilityStandard subdivisions are added for either or both topics in heading

RI: Probabilities—epistemology (AW)

Matching RI terms to topics:IN match

620 Engineering

627.52      IrrigationClass here construction and use of irrigation canals

RI: Irrigation canals—engineering (AW)

Matching RI terms to topics:KEYWORD match

384.14      *Activities and servicesIncluding Morse and other code telegraphy, printing telegraphy; stock tickers, teletype, telex; comprehensive works on facsimile transmission

RI: Morse code telegraphy (SR)

Matching RI terms to topics:KEYWORD match384.51      *Satellite communication RI: Communications satellites (AW)

384.54      *RadiobroadcastingClass here public broadcasting (noncommercial broadcasting), public aspects of amateur radio, interdisciplinary works on radiobroadcasting and television broadcasting

RI: Noncommercial radio (AW)

Matching RI terms to topics:PARTIAL (50%+) match

748    Glass

748.6      Methods of decoration RI: Decorative treatment—glass (AW)

Results

EXACT IN KEYWORD

PARTIAL

TOTAL

Approximates whole

11335(24.4%)

4209(9.0%)

1241(2.7%)

5189(11.2%

)

21974(47.2%)

Standing room

3116(6.7%)

4064(8.7%)

952(2.0%)

1513(3.3%)

9645(20.7%)

Unknown status

1042(2.2%)

1479(3.2%)

584(1.3%)

1091(2.3%)

4196(9.0%)

Total 15493(33.3%)

9752(21.0%

)

2777(6.0%)

7793(16.8%

)

35815(77.0%)

Future improvements (1)

Observe hierarchical force302 Social interaction

Class here . . . social psychology302.24 Content

Including gossip, rumor RI: Rumor—social psychology

Future improvements (2)

Don’t require match on Relative Index qualifier

335.2 Systems of French originIncluding Babouvism, IcarianismRI: Babouvism (Socialist school)

Future improvements (3)

Introduce stopwords for general terms

748    Glass

748.6      Methods of decoration RI: Decorative treatment—glass (AW)

Future improvements (4)

Locally reverse treatment of main heading and subheading

220 The Bible224 Prophetic books of Old Testament224.1 Isaiah (Isaias)

RI: Bible. O.T.--Isaiah