The Changing Face of Okapi

Describes the Okapi projects and Okapi′s development as an experimental online catalogue system over ten years. The first Okapi project in 1984 introduced “best match” retrieval and focused on the user interface design. The second investigated word stemming, spelling correction and cross‐reference tables as retrieval aids. A comparative study of two library catalogues was undertaken in 1987, while in 1988 query expansion and relevance feedback were introduced and evaluated by laboratory tests. Live evaluation of automatic query expansion in an online catalogue and an online database was carried out in 1990. In 1993, subject enhancement of bibliographic records was investigated. The latest project has examined the design of a graphical user interface to support interactive query expansion. Discusses the research and evaluation of each project.