HOW MUCH ‘EXPLICIT RELATIONS’ DO RETRIEVAL SYSTEMS USE?

Cranfield II's findings on the unexpectedly low retrieval performance of thesauri (rank order 19 among 33 index languages) led Cleverdon to conclude that ‘there are situations where the intellecutal effort involved in the construction and maintenance of controlled vocabularies is unjustified.’ Lancaster has cited the figure of more than half a million dollars, appropriated for the construction of TEST, the Thesaurus of Engineering and Scientific Terms. Recently Keen has provided some additional information, casting further doubts on the utility, in serious retrieval work, of any explicit display of relations between terms.