The overall aim of the field trial evaluation was to determine how searchers would make use of different facilities for formulating and enhancing queries. The ENQUIRE system offered a range of possible strategies which could be initiated either automatically by the system, or interactively with the user, at different stages of a search. In developing the system the design issues had centred on what facilities would be made available, and how they should be implemented to allow for more effective interaction between the system and the user in the query formulation and reformulation tasks.
The formative evaluations served to establish the appropriateness and usability of the new Okapi interface, as well as users' perceptions of the new underlying functionality. The outcome of the initial evaluation was a fully operational prototype system, offering what were considered to be the best design solutions for presenting and supporting query formulation and enhancement. The system set up for the summative evaluation was deemed suitable for any category of end user within the two academic institutions, and hence the investigation focused on searching behaviour at the task level. The test subjects were self-selected and carried out searches of their own choice. The comparative results of the data about searching behaviour collected at the two sites reveal a number of common patterns, but some differences emerged, particularly in the way searches were reformulated.