Use of Multiword Terms and Query Expansion for Interactive Information Retrieval

This paper reports our participation in the INEX 2008 AdHoc Retrieval track. We investigated the effect of multiword terms on retrieval effectiveness in an interactive query expansion (IQE) framework. The IQE approach is compared to a state-of-the-art IR engine (in this case Indri) implementing a bag-of-word query and document representation, coupled with pseudo-relevance feedback (automatic query expansion(AQE)). The performance of multiword query and document representation was enhanced when the term structure was relaxed to accept the insertion of additional words while preserving the original structure and word order. The search strategies built with multiword terms coupled with QE obtained very competitive scores in the three Ad-Hoc tasks: Focused retrieval, Relevant-in-Context and Best-in-Context.