Transaction logging has been used extensively in Okapi‐related projects to allow search algorithms and user interfaces to be investigated, evaluated and compared. Logging software may be independent of the system being examined, or integrated with it. Logging is undertaken for various...

At the heart of the Okapi system is a formula referring to some half a dozen variables, which estimate the probability that a given document is relevant to a given query. User interface design for Okapi aims to present its search capabilities as clearly and simply as possible. But between the...