COMPILING A TECHNICAL THESAURUS

A thesaurus is defined as a device for controlling and displaying an indexing vocabulary. The vocabulary is controlled in the sense that the individual terms are carefully chosen and appear as distinct, though not inseparable, entities it is displayed in such a way as to provide ready access from a given entry to related words that may be needed to index a paper or phase a search question. Some factors that may be considered in formulating the vocabulary for the thesaurus are discussed in terms of experience in compiling The Thesaurus of ASTIA Descriptors. Among the basic criteria to be examined are 1 the volume and scope, in terms of scientific disciplines involved, of the collection to be indexed, 2 the technical competence of those indexing and retrieving the information, 3 the resources, including time, money, and equipment, to be devoted to the retrieval system as a whole and 4 the demands, in terms specificity of information, and speed of service that must be satisfied by the system. Problems that must be dealt with in evaluating the individual terms include 1 synonyms, 2 homographs, 3 generic relationships, 4 logical relationships and 5 proper degree of specificity. Effective display of the vocabulary encompasses format of cross references, methods of delimiting meanings of terms, and graphic displays of related terms.