The PREserved Context Index System (PRECIS) developed for subject indexing for the British National Bibliography is discussed as a basis for various studies relating to classification which could be made from its initial phrases, strings, entries, and back-up structure. (Author)

Outlines a methodology for standardizing word lists of subject- related fields using a macrothesaurus which provides basic classification structure and terminology for the subject at large and which adapts to the specific needs of its subfields. The example of the Cancer Information Thesaurus (CIT) is detailed. Six references are listed. (FM)