A server is configured to receive a search query from a client device; identify documents as search results relevant to the search query, where each of the search results has a respective first score; rank the search results, based on the respective first scores, to form a ranked list of search results, where each of the search results has a respective position, within the ranked list, that is based on the ranking; determine a selection rate corresponding to each of the positions in the ranked list; identify categories with which the search results are associated; generate second scores for the categories based on the selection rates; select search results for the selected categories; generate a search result document that includes information regarding the selected categories and information regarding the selected search results; and provide the search result document for display on the client device.