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

Networked and local data exploration systems that use command languages, menus, or form ® ll-in interfaces rarely give users an indication of the distribution 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 approach for browsing databases. Query previews supply users with data distribution information for selected attributes of the database, and give continuous feedback about the size of the result set as the query is being formed. Subsequent re® nements might be necessary to narrow the search. As there is a risk that query previews are an additional step, leading to a more complex and slow search process, a within-subjects empirical study was ran with 12 subjects who used interfaces with and without query previews and with minimized network delays. Even with 12 subjects and minimized network delays statistically signi® cant diVerences were found, showing that query previews could speed up performance 1.6 to 2.1 times and lead to higher user satisfaction.