are lcsh still effective?
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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…. - PowerPoint PPT PresentationTRANSCRIPT
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?