Library and Information Science

The problems of thesauri for document retrieval have been discussed in many papers so far, and guidelines for the establishment of thesauri have already been published by UNESCO and ISO.

The guidelines are very insufficient concerning the purpose and criteria for preferential cross-referencing between the descriptor and the non-descriptor, and for hierarchical and associative cross-referencing between descriptors.

The author thinks that this insufficiency is due to lack of consideration of what documents are necessary to get the answer to a request, including the term or the concept discussed. In these guidelines only synonymous, generic and part-whole relations between terms are mentioned as basis for preferential and hierarchical cross-references.

In spite of the lack of clear description of this viewpoint in the guidelines, in various existing thesauri cross references between terms are made, on the basis of relations between documents.

For example, the Engineers Joint Council thesaurus, which restricts hierarchical cross-references primarily to generic relations, adopts relations other than synonymous and generic ones as basis for preferential cross-referencing.

Reviewing the above-mentioned guidelines and examples in existing thesauri in terms of definition of thesaurus, selection of descriptors, cross-references between terms, special procedures for generic terms, and methods of compiling thesaurus, the author discusses specific problems and suggests some solutions.