Facilitating data exploration with query previews: a study of user performance and preference

Networked and local data exploration systems that use command languages, me nus, or form fill-in interfaces rarely give users an indication of the dist ribution of data. This often leads users to waste time, posing queries that have zero-hit or mega-hit results. Query previews are a novel visual appro ach for browsing databases. Query previews supply users with data distribut ion information for selected attributes of the database, and give continuou s feedback about the size of the result set as the query is being formed. S ubsequent refinements might be necessary to narrow the search. As there is a risk that query previews are an additional step, leading to a more comple x and slow search process, a within-subjects empirical study was ran with 1 2 subjects who used interfaces with and without query previews and with min imized network delays. Even with 12 subjects and minimized network delays s tatistically significant differences were found, showing that query preview s could speed up performance 1.6 to 2.1 times and lead to higher user satis faction.