are lcsh still effective? why not use keyword searching instead? presented by carol bradsher october...

Are LCSH still effective?Why not use keyword

searching instead?

Presented by

Carol Bradsher

October 29, 2004

Problems What are the problems with

subject analysis in general and the Library of Congress Subject Headings, specifically?

Survey says… Complexity, which impacts ability of

catalogers to assign and general public to use 75% of users do not understand; 50% of librarians don’t either;

No guidance on determining “aboutness” Inconsistency of heading assignment,

influenced by subjectivity, cultural biases, differing perspectives of catalogers

Aboutness… Assigning subject

headings is an art, not a science

Cataloging standards favor the known item

This boils down to… Subject search is the most widely used

(50% of catalog searches are subject searches) and the most frustrating one for information seekers

WHAT THE HELL DO YOU MEAN NO MATCH FOUND?

Discussion point What are the advantages of

controlled vocabulary? Advantages of keyword searching? Disadvantages of keyword?

Advantages of controlled vocabulary Can handle variations in language

and terminology Synonyms Homographs

Can combine terms into phrases, relate phrases to one another

Cross reference structure to direct users to valid terms

Advantages of keyword Greater recall Requires less knowledge to search Can access entire bibliographic

record, table of contents, summary pre-coordinate indexing vs. post-

coordinate, which allows multiple headings to be accessed (Dancers AND Musicians)

Disadvantages of keyword

Success of keyword searching depends on 2 assumptions:

1. Authors writing about the same concepts will use the same words in their writings;

2. Searchers will be able to guess what words those authors used for the concepts

Language—the biggest obstacle for keyword searching

Synonyms Homographs Determining the meaning of words

Synonyms Words can have the same

meaning, or not, e.g. Attire, dress, clothing Various styles of dress She is wearing a lovely dress

Synonyms Singular vs. plural form doesn’t

always have the same meaning Apple (fruit and/or tree) Apples (fruit only) Art (visual art) Arts (various subdisciplines including

visual, literature, performing)

What about synonym lists? not large or general enough Implemented in small and specialized

domains No knowledge of adjectives and nouns

and which kind of words could be used together to make a phrase

Aircraft = planes

Big = large

Big aircraft = large planes

Homographs Words that look the same but have

different meanings: Mercury: liquid metal, planet, car,

Roman God or Freddie Bridge: structure, dental device, card

game, musical conveyance

Keyword’s biggest weakness “Subject analysis so far has defied

automatic techniques such as word counting; only a human can attach words to a concept that is the subject of a document but is never explicitly named in that document.” -- Arlene Taylor

What’s the solution? Disadvantages to both controlled

vocabulary and keyword, what do we do? Throw out LCSH Throw out keyword Start over?

Suggested solutions Hildreth: keep LCSH, change

automated systems so they search more intelligently

Index worthy books Paul Frantz: expand scope of EGLI

and use it to address content of nonfiction books contained in the Book Review Digest (ca. 5000 titles)

Could be accomplished by 3 or 4 catalogers doing 7-8 books per day

Standardize order of subdivisions in LCSH Study by Karen Drabenstott (1998) on

understanding subject headings Endorses recommendation of Subject

Subdivision conference (1991) Simplify cataloging and save money

No training needed on the ordering of subdivisions

Staff time saved in verification Makes machine verification of headings

possible

FAST OCLC research project, Faceted

Application of Subject Terminology Derived from LCSH, but simpler

syntax Intended audience: web resources

FAST background Response to an ALCTS subcommittee

recommendation for subject analysis of web resources

Built on LCSH to take advantage of: Existing schema with strong history and LC

support rich terminology Extensive use

Post-coordinate searching Dogs AND Housing

Mechanics6 facets at this point:

1. Topical (includes topical subdivisions)2. Geographic3. Form4. Period5. Personal name6. Corporate name

(rest to be added later)

New rules Everybody in the pool!

All topical headings and their subdivisions in the Authority File as strings

West Side Story for subdivisions stick with your own kind, topical headings

subdivided by topical sbd, geographic headings by geographic sbd, etc.

Back to the future Geographic headings formulated in indirect

order, e.g. Ohio—Columbus; Ohio—Columbus—German Village

examples

LCSH:650 Authority files

(Information retrieval) $z Italy $z Florence $v Congresses

FAST:Topical: Authority

file (Information retrieval)

Geographic: Italy $z Florence

Form: Congresses

Summary What’s our purpose today?