5. The computer-implemented method of claim 1 , wherein the candidate query is further selected in response to determining that a quality score for the revised query is greater than a quality score threshold and that a navigation score for the revised query is greater than a navigation score threshold.
8. The computer-implemented method of claim 5 , wherein the quality score for the revised query is determined by: determining resource metrics for each resource identified by a search engine in response to the revised query, the resource metrics including one or more of an authority score and a search result click-through rate; and determining revision metrics for the revised query, the revision metrics including one or more of a revision frequency and a revision time; wherein: the authority score is a score of a node in a link graph and that is representative of the resource; the revision frequency is frequency at which the revised query is further revised in search sessions; the revision time is a time measured relative to the entry of the candidate query; and the click-through rate is a rate at which one or more search results for the revised query in response to the search operation are selected.