LIS 6771 Indexing with a Controlled Vocabulary Basic Concepts

LIS 6772 Indexing: Topics Covered The “concept triangle”concept triangle The five-axiom theory of indexingfive-axiom theory of indexing The indexing processindexing process

LIS 6773 The “Concept Triangle” Referent Concept Expression

LIS 6774 The Referent “The referent is everything about which a meaningful statement can be made.” For example, about a certain table many statements can be made concerning the material of which it is made, its price, purpose, producer, weight, the structure of its surface, etc.

LIS 6775 The Concept “We define the concept as the sum of the essential statements that can be made about a referent.” Essential statements are those which contribute to the characterization of the referent itself. Inessential statements are those which do not contribute to the characterization of the referent itself.

LIS 6776 Kinds of Concepts General concepts The general concept describes a class of interrelated referents. For example: metal, oxidation, information Individual concepts The individual concept is one to which no meaningful conceptual feature can be added. For example: Albert Einstein; Fritz the Cat.

LIS 6777 General vs. Individual Concepts in Indexing “It is the task of subject indexes to provide access to documents or text passages relevant to general concepts.” “An information system which works quite well for individual concepts, may totally fail when it is required to manage general concepts too.”

LIS 6778 The Mode of Expression Lexical expressions linear strings of characters commonly agreed upon to express concepts or concept connections Non-lexical expressions linear strings of characters by which concepts or concept relations are expressed and upon which no firm agreement has been made

LIS 6779 Forms of Expression & Indexing Lexical expressions require little indexing work Often appear in Identifier fields rather than in Descriptor fields of database records Non-lexical expressions require indexing work non-lexical expressions exhibit ambiguity and multiplicityambiguity and multiplicity

LIS Concepts & Expressions Individual concepts are almost always expressed lexically General concepts are almost always expressed non-lexically In natural, uncontrolled language there is an unlimited multitude of non-lexical, paraphrasing expressions for concepts Multiplicity & ambiguity of natural language expressions are largely restricted to general concepts

LIS Five-Axiom Theory of Indexing Definability Order Sufficient degree of order Representational predictability Representational fidelity

LIS Axiom of Definability The compilation of information relevant to a topic can be delegated (to a skilled specialist or a programmed search mechanism) only to the extent to which the inquirer can define the topic in terms of concepts and concept relations.

LIS Axiom of Order Any compilation of information relevant to a topic is an order-creating process. Order is defined as the meaningful proximity of the parts of a whole at a foreseeable place.

LIS Axiom of Sufficient Degree of Order The demands made on the degree of order increase as the size of the collection and/or the frequency of the searches and/or the specificity of the searches increases.

LIS Axiom of Representational Predictability The completeness of any search for documents relevant to a topic of interest depends on the predictability of the modes of expression for concepts in the search file. Successful searches require a language with predictable modes of expression for concepts.

LIS Axiom of Representational Fidelity The precision of any search for documents relevant to a topic of interest depends on the fidelity with which the modes of expression for concepts can be expressed in the system’s language.

LIS The Indexing Process Step 1: Determine the essence of a document Step 2: Represent this essence with sufficient degrees of predictability and fidelity

LIS Importance of Categories “The predictability of essence selection is markedly enhanced when the indexers have an orientation to conceptual categories.” For example, in some chemistry databases, all descriptors belong to the following categories: MATTER LIVING ENTITY APPARATUS PROCESSS In ERIC, the nine Descriptor Groups serve as categories.

LIS Natural Language Indexing “Natural language expressions, as derived from original texts, can only in the case of individual concepts lead to an information system of adequate quality and survival power.” The specificity of natural language expressions is compromised by their lack of predictability.

LIS Importance of “Cutter’s Rule” Precise and complete searches require that the most specific descriptors that the vocabulary provides be chosen for the indexing of a subject. A query with a specific descriptor must not retrieve concepts that are more general than the search descriptor.

LIS Importance of Syntax In the interests of enhanced representational fidelity any advanced indexing language needs a syntax in addition to its vocabulary. The syntax should represent the manner in which the concepts are connected with each other in the texts to be stored.