12 Retrieval system tests 1958 - 1978

Previous chapters considered the problems of information retrieval experiment in general, and particular types of experiment. This chapter looks at information retrieval experiment over the last twenty years as a whole, to see what the actual tests which have been carried out show. I shall not attempt an exhaustive review of this work. I shall seek rather to characterize it by referring on the one hand to especially significant tests, and on the other to average or representative ones. My object is to exhibit the development of retrieval experiment in the last two decades in terms of the purpose, quality and influence of the tests which have been carried out. The twenty year period for the survey is a natural one, since it effectively covers the development of modern, especially computer-based, retrieval systems, and equally, most of the significant information retrieval tests.