PERSONALIZED QUERY SUGGESTIONS FROM PROFILE TREES

Methods, systems, and apparatus, including computer program products, for personalized query suggestion are disclosed. The personalized query suggestion utilizes a personalized profile tree constructed using search history associated with a user. The personalized profile tree is a hierarchy of nodes representing categories of information that the user has previously searched or selected from search results. When a search query is received from the user, a ranked list of related queries can be generated for the received search query. Each of the related queries is compared against the nodes in the personalized profile tree, and a relevance score is given to the related query based on the depth of a matching node in the tree, and a child count for the matching node. The related queries are re-ranked based on their respective relevance scores. After the re-ranking, top-ranked related queries are presented to the user as query suggestions.