Controlling values The equivalence relationship The vocabulary

Controlling values The equivalence relationship

The vocabulary problem What is this?

Synonymy Restroom, bathroom, toilet, loo, facilities, WC, ladies’ room, mens’ room, little girls’ room, little boys’ room. . . Synonymy: Using different words to identify the same concept.

Another vocabulary problem What is mercury? What is bank? What is python? What is java?

Polysemy: Using the same word (morphologically speaking) to identify different concepts. Java: Island in Indonesia, specific variety of coffee bean, generic term for coffee, objectoriented programming language.

Yet more vocabulary problems The White House has been lobbying Congress to support the proposed budget. . . Freedom of the press is an important value in the United States. . . I’m tired of taking the bus; I need some new wheels. . .

Metonymy and synecdoche Metonymy: Using a related concept to stand for another concept. Synecdoche: Using the word for part of something to stand for the entire thing.

Furnas, et al’s experiment Furnas, et al asked people (including subject experts) to label a variety of items (recipes, text editing operations, “common content objects”). Surprise, there was little agreement among the names submitted by participants. Conclusion: “The idea of an ‘obvious, ’ ‘self-evident, ’ or ‘natural’ term is a myth! Since even the best possible name is not very useful, it follows that there can exist no rules, guidelines or procedures for choosing a good name, in the sense of ‘accessible to the unfamiliar user. ’

Furnas, et al’s recommendations Furnas, et al suggest that interface designers: • Implement unlimited aliasing. • Disambiguate terms that can be used in multiple senses by presenting possibilities to users and asking them to select the appropriate one.

Limitations of Furnas’s study • Participants were asked to label objects, not how they would search for objects. • The study assumes a search interface, not a browsing (or menu-driven) interface. In a search interface, users must recall or guess an object’s name. In a browsing interface, users merely need to recognize the appropriate term.

Vocabulary problems and information systems Designers of organizational systems have been grappling with the ambiguities of language for many years. Synonymy, polysemy, and so on complicate the goal to collocate, or bring together, like items in an information system (those by the same author, with the same title, or on the same subject).

Vocabulary control In LIS, vocabulary control is similar to Furnas’s idea of aliasing: multiple terms that might stand for the same concept are grouped together. One term is typically designated as preferred: this is the term used in a display (or, in a card catalog, the card with the preferred term would actually have the entry; the other terms would just be cross-references).

Example of a controlled term Preferred term: bathroom Equivalent terms: restroom, loo, toilet, WC, ladies’ room, mens’ room, little girls’ room, little boys’ room, ladies room, lady’s room, ladie’s room, ladys’ room. . .

Digression into the library catalog Library catalogs have three traditional access points: author, title, and subject. In the old card catalog, these were three ways that users could search. Each of these access points has associated vocabulary control.

Catalog entries Entry is an old term for a catalog record. For example, Herman Melville’s Moby Dick might have an entry in the card catalog under the subject Fiction—Whaling. The main entry designates the primary access point and, in the card catalog, the card with all the bibliographic information. (Other entries might have a cross-reference to the main entry only. ) The entry for Moby Dick under Fiction—Whaling might say merely “See Melville, Herman. Moby Dick. ”

Main entry confusion For many people, the designation of a primary access point or main entry is anachronistic in the world of online systems. We can search any attribute now: why select a “primary” one? Taylor notes three arguments for retaining the main entry: standardization of citation, subarrangement, and collocation of works.

Control of names Names, such as author or title names, are controlled via authority files. Authority files both disambiguate names that identify multiple people or items and group variations for the same person or item (that is, they deal with polysemy and synonymy).

Authority file examples In the UT authority file: headings for Patricia Williams: • Names are disambiguated by using middle initials and dates of birth. • Cross references are used for some authors. • There may still be two headings for one person!

Digression 2: Power catalog searching To increase the precision in library catalog searches, avoid keyword searching. Instead, search the appropriate authority file first, then search using the preferred heading. Magic! Searching the authority file typically necessitates proper query formation (e. g. , last name, first name for author searches).

Digression 3: Pseudonyms in the catalog Pseudonymous identities are maintained in AACR 2 (in older catalogs, everything went under the author’s real name). For example, “Carolyn Keene, ” the name used by multiple people as the author for the Nancy Drew novels, is maintained as an author entity in the authority file.

Controlled subject vocabularies Subject vocabularies have varying amounts of structure (e. g. , relationships between terms). Thesauri may include equivalence, hierarchical, and associative relationships. Thesauri can also be faceted (that is, represent multiple aspects of a subject. . . we will discuss facets in depth later in the course).

Example thesaurus entry Dark chocolate BT Chocolate RT Single-origin chocolate UF Semisweet chocolate Baker’s chocolate Sweet chocolate SN Chocolate without milk solids and with less than 70 percent chocolate mass. BT: broader term, one level up in a hierarchy RT: related term, in another facet or hierarchical branch UF: Use for; synonyms, or nonpreferred terms SN: Scope note; definitions or usage guidelines

Equivalence in thesauri Similar concepts may be treated as equivalents as judged appropriate by thesaurus designer. Examples: Beer UF ale, porter, stout, pilsner, bock, IPA. . . Cartography UF maps

Disambiguation in thesauri Polysemous terms are often identified by adding qualifying terms in parentheses. Mercury (element) Mercury (god in Greek mythology) Search engines may use ask users to select the sense they want.

Using controlled vocabularies: Me. SH and Pub. Med The Medical Subject Headings (Me. SH) index journal articles for the Pub. Med database. Keyword searches in Pub. Med are automatically expanded with Me. SH. Searches can also be explicitly limited to Me. SH terms, which can increase precision. The comparison to a system like Google Scholar is illuminating.

Standards for controlled vocabularies There a number of standards for thesaurus construction: ISO, NISO, British. These can be quite detailed, but they provide mostly syntactic guidance: e. g. , terms should take noun form.

Summary • Controlled vocabularies increase precision and recall in searching by identifying equivalent terms. • Authority files are types of controlled vocabularies that describe preferred forms of author names and names of works. • Thesauri are subject-based controlled vocabularies that include hierarchical and associative relationships in addition to equivalence relationships. Thesauri can also be used as browsing interfaces.