EVALUATING THE ECONOMIC EFFICIENCY OF A DOCUMENT RETRIEVAL SYSTEM Available to Purchase

A retrieval system may be evaluated strictly in terms of user satisfaction (operating efficiency), or it may be evaluated from the point of view of efficient means of satisfying user requirements (economic efficiency). When we consider the relationship between operating efficiency and economic efficiency, we are faced with a whole series of possible trade‐offs. There may be several alternative paths we can follow in order to serve user needs. The problem is to determine the most economical path to follow. Pay‐off factors, break‐even points, and diminishing returns must be taken into consideration. This paper considers some of these factors in relation to various parts of the complete retrieval system: the acquisition subsystem, the indexing subsystem, the index language, the searching subsystem, and the equipment subsystem.