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Types of Indexing Languages

Types of Indexing Languages. Charlyn P. Salcedo Instructor. 1. Natural language (derived-term system)‏ Characteristics are: Improves recall because it provides more access points but reduces precision Redundancy is greater Uses more current terms

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Types of Indexing Languages

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  1. Types of Indexing Languages Charlyn P. Salcedo Instructor

  2. 1. Natural language (derived-term system)‏ Characteristics are: • Improves recall because it provides more access points but reduces precision • Redundancy is greater • Uses more current terms • Tends to be favored by subject-specialists or the end-users • May also be called indexing by extraction (or extractive indexing method).

  3. 2. Controlled vocabulary (assigned-term system)‏ Functions: • To control synonyms by choosing one form as the standard term • To make distinctions among homographs • To bring or link together terms that are closely related • Establishes the size of scope of a term • Usually records hierarchical and affinitive/associative relations • Controls variant spellings

  4. Syndetic devices used by a controlled vocabulary: • USE and UF(use for) for synonyms • BT(broader term), NT(narrower term) andRT(related term) for differing levels of specificity and certain near synonyms and antonyms

  5. Advantages of Controlled Vocabulary Language • Increases the probability that both indexer and searcher will express a particular concept in the same way. • Increases the probability that the same term will be used by different indexers or by the same indexer at different times. • Helps searchers to focus their thoughts when they approach the information system without a full and precise realization of what information they need.

  6. Disadvantages of Controlled Vocabulary Language: • Incompatibility of different indexing languages. • High input cost. • The possibility of inadequate vocabulary.

  7. Types of Controlled Vocabulary Authority List / Subject Authority List a related group of words or phrase adopted by a particular group of people. Examples: • Library of Congress Subject Headings • Sears List of Subject Headings • Dewey Decimal Classification

  8. Thesaurus • Latin word means ‘treasure’, & is used to control indexing vocabulary • It is a set of terms structured using a small set of semantic relationships between the term/ concepts. • Poly-hierachical Examples: • The Art & Architecture Thesaurus* • ERIC (Education Resouces Information Center) Thesaurus*

  9. Similarities between Authority Lists and Thesauri • Both attempts to provide subject access to information resources by providing terminology that can be consistent rather than uncontrolled and unpredictable. • Both choose preferred terms and make references from non-used terms. • Both provide hierarchies so that terms are presented in relation to their broader, narrower, and related terms.

  10. Difference between Authority Lists and Thesauri • Thesauri are made up of single terms and bound terms representing single concepts. Subject heading lists have phrases and other pre-coordinated terms in addition to single terms. • Thesauri are more strictly hierarchical. • Thesauri are narrow in scope. • Thesauri are more likely multilingual.

  11. Relationships of Terms INTELLIGENCE BT: Ability NT: Comprehension RT: Talent Aptitude • Broader term (BT)reference shows hierarchical relationship upward in the classification tree. • Narrower term (NT)reference is similar to the broader term reference, except it goes down in the classification tree. • Related term (RT)reference refers to a descriptor that can be used in addition to the basic term but is not in a hierarchical relationship.

  12. Use for (UF) reference deals primarily with synonymous or variant forms of the preferred descriptor. It is also used to lead the indexer to more general terms. • TREES UF Pecan trees • PROMOTION POLICIES UF Automatic promotion

  13. Usereference refers to a preferred descriptor from a non-usable term. Examples: • Pecan trees USE TREES • Oak trees USE TREES

  14. Scope Note (SN) is used to give the users about the descriptor’s usage restrictions or to clarify ambiguity. Example: CULTURAL BACKGROUND SN: The total social heritage and experience of an individual or group including institutions, folkways, literature, mores, and communal experience.

  15. Construction of a Thesaurus • Identify the subject field. • Identify the nature of literature to be indexed. • Identify the users. • Identify the file structure. Will this be a pre-coordinate or post-coordinate system? • Consult published indexes, glossaries, dictionaries, and other tools in the subject areas for the raw vocabulary. • Cluster the terms. • Establish term relationships.

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