Query Formulation for XML Retrieval with Bricks

XML retrieval, also referred to as Structured Document Retrieval is a discipline of information retrieval that focusses on the retrieval of relevant document fragments for a given information need that contains both structural and textual components. In this article we will focus on the theory behind Bricks, a visual query formulation technique for XML retrieval that aims at reducing the complexity of the query formulation process and required knowledge of the underlying document structure for the user, while maintaining full expression power, as offered by the NEXI query language for XML retrieval. In addition, we present the outcome of a large scale usability experiment, which compared Bricks to a keyword-based and a NEXI-based interface. The results showed that participants were more successful at completing a number of search assignments using Bricks or NEXI. Furthermore, we observed that the participants were also able to successfully complete their assignments in a significantly shorter period of time, when using the Bricks interface.