The use of thesauri in online retrieval

Abstract

The controlled vocabulary versus the free text approach to information retrieval is reviewed from the mid 1960s to the early 1980s. The dominance of the free text approach following the Cranfield tests is increasingly coming into question as a result of tests on existing online data bases and case studies. This is supported by two case studies on the Coffeeline data base. The differences and values of the two approaches are explored considering thesauri as semantic maps. It is suggested that the most appropriate evaluatory technique for indexing languages is to study the actual use made of various techniques in a wide variety of search environments. Such research is becoming more urgent. Economic and other reasons for the scarcity of online thesauri are reviewed and suggestions are made for methods to secure revenue from thesaurus display facilities. Finally, the promising outlook for renewed develop ment of controlled vocabularies with more effective online display techniques is mentioned, although such development must be based on firm research of user behaviour and needs.