I am working on many aspects related to information retrieval. From 2002 to 2007, I co-led the INEX initiative, which is the evaluation forum for XML retrieval. My current research themes include aggregated search, measuring user engagement, and technology for bridging the digital divide.

From January 2011, I will work at Yahoo! Research in Barcelona as a visiting principal scientist, and will become a honorary research fellow at the University of Glasgow.

From September 2008 to December 2010, I held a Microsoft/Royal Academy of Engineering Research Chair in Information Retrieval at the University of Glasgow, where I worked on applying the quantum theory formalism to model information retrieval processes. Before joining Glasgow, I was a Professor of Information Retrieval at Queen Mary, University of London, which I joined in January 1999 as a lecturer (aka assistant professor).