(Su, 1992). However, user-centric approaches are
less scalable and repeatable than system-centric approaches (Huffman & Hochster,
2007). Since the ultimate goal of any IR evaluation is to assess the probability of an IR
system being both adopted and used, potential end-users must be involved. Therefore,
by retrieval effectiveness we mean users' perceived relevance of retrieved results w.r.t.
the users' queries. That is, we seek to enhance precision of results without adding
significant complexity on user interaction.