1. A method comprising: incorporating a set of instructions into one or more memories of a social networking service, the set of instructions configuring one or more computer processors of the social networking service to perform operations for improving a search results user interface of the social networking service by adjusting positioning of search results presented in the search results user interface based on work histories, the operations comprising: processing a search query initiated by a searcher to identify a set of member profiles satisfying the search query, the set of member profiles corresponding to a set of members of the social networking service; assigning a ranking score to each member profile of the set of member profiles based on a ranking criterion; identifying a subset of the set of member profiles based on a determination of an overlap between a work history specified in each of the subset of member profiles and a work history specified in a profile of the searcher, the overlap pertaining to dates of employment at a particular employer included in the work history specified in each of the subset of member profiles and included in the work history specified in the profile of the searcher, the identifying of the subset of the set of member profiles further based on a determination of an overlap between a work history specified in each of the subset of member profiles and a work history specified in a profile of a connection of the searcher; adjusting the ranking score assigned to a member profile of the subset of the set of member profiles based on the determination, an amount of the adjusting of the ranking score based on a length of the overlap and a degree of relatedness of the overlap between the member profile of the searcher and the member profile of the subset of the member profiles; and communicating, for presentation as search results in a search results interface, a portion of each of the set of member profiles satisfying the search query, the search results positioned to reflect the ranking score assigned to each of the member profiles of the set of member profiles, including the adjusted ranking score assigned to the member profile of the subset.