Im some recent experimental document retrieval systems, emphasis has been placed on the acquisition of a detailed model of the information need through interaction with the user. It has been argued that these "enhanced" queries, in combination with relevance feedback, will improve retrieval performance. In this paper, we describe a study with the aim of evaluating how easily enhanced queries can be acquired from users and how effectively this additional knowledge can be used in retrieval. The

more »

... sults indicate that significant effectiveness benefits can be obtained through the acquisition of domain concepts related to query concepts, together with their level of importance to the information need.