Search Result Diversification

Ranking in information retrieval has been traditionally approachedas a pursuit of relevant information, under the assumption that theusers' information needs are unambiguously conveyed by their submittedqueries. Nevertheless, as an inherently limited representation of amore complex information need, every query can arguably be consideredambiguous to some extent. In order to tackle query ambiguity,search result diversification approaches have recently been proposed toproduce rankings aimed to satisfy the multiple possible informationneeds underlying a query. In this survey, we review the published literatureon search result diversification. In particular, we discuss themotivations for diversifying the search results for an ambiguous queryand provide a formal definition of the search result diversification problem.In addition, we describe the most successful approaches in theliterature for producing and evaluating diversity in multiple search domains.Finally, we also discuss recent advances as well as open researchdirections in the field of search result diversification.