A study of user interaction with a concept-based interactive query expansion support tool

A medium-scale user study was carried out to investigate the usability of a concept-based query expansion support tool. The tool was fully integrated into the interface of an IR system, and designed to support the user by offering automatically generated concept hierarchies. Two types of hierarchies were compared with a baseline. Several observations were made as a result of the study: 1) the hierarchy is often accessed after an examination of the first page of search results; 2) accessing the hierarchies reduces the number of iterations and paging actions; 3) accessing the hierarchies increases the chance of finding relevant items more accurately than the baseline; 4) the hierarchical structure helps the users to handle a large number of concepts; and finally, 5) subjects were not aware of the difference between two types of hierarchies.