BROWSING HIERARCHICAL DATA WITH MULTILEVEL DYNAMIC QUERIES AND PRUNING

Users often must browse hierarchies with thousands of nodes in search of those that best match their information needs. The PDQ Tree-browser (Pruning with Dynamic Queries) visualization tool was specified, desi gned and developed for this purpose. This tool presents trees in two t ightly-coupled views, one a detailed view and the other an overview. U sers can use dynamic queries, a method for rapidly filtering data, to filter nodes at each level of the tree. The dynamic query panels are u ser-customizable. Sub-trees of unselected nodes are pruned out, leadin g to compact views of relevant nodes. Usability testing of the PDQ Tre e-browser, done with eight subjects, helped assess strengths and ident ify possible improvements. The PDQ Tree-browser was used in Network Ma nagement (600 nodes) and UniversityFinder (1100 nodes) applications. A controlled experiment, with 24 subjects, showed that pruning signific antly improved performance speed and subjective user satisfaction. Fut ure research directions are suggested. (C) 1997 Academic Press Limited .