Multi-session re-search: in pursuit of repetition and diversification.

Search engine users regularly re-issue queries that are the same or similar to ones they have previously issued. In this paper we study this act of query re-issuing, called re-search, focusing on multi session re-searching from an information seeking perspective. By focusing on the series of repeat or similar queries where the user shows a continued interest, new patterns of behavior not previously seen arise. We find that the well-studied re-finding behavior is only a piece of the re-search puzzle, and that even amidst repeated re-findings users exhibit diversification and novelty seeking behaviours for many re-search queries. This suggests diversity and re-finding behaviors should be jointly modelled and captured in evaluation measures, instead of being studied as two separate problems as is seen in many previous approaches.