REDUNDANCY, RELEVANCE, AND VALUE TO THE USER IN THE OUTPUTS OF INFORMATION RETRIEVAL SYSTEMS

A test was carried out to investigate the assumption that there is a significant level of redundancy (or notional overlap) between documents. The first part of the paper derives a measure of notional overlap, which is then applied to a test collection of 455 documents in the general subject area of computer applications to air traffic control. The conclusions were that notional overlap exists, but there appear to be very few cases of extreme redundancy, and at the document level, there is little possibility of practical application.