My clients and students frequently ask me what determines the search rankings on LinkedIn. Some of the ranking factors are obvious as I’ve shown in previous examples. Use your target keywords as your last name field, in your professional headline and in your profile summary. As obvious as these seem, LinkedIn doesn’t officially tell us what determines our search rank. Here is what LinkedIn officially tells us.
LinkedIn uses proprietary algorithms to rank and order the results you get when you search for people on the site.
To learn more about LinkedIn's ranking factors visit http://help.linkedin.com/app/answers/detail/a_id/4447/~/linkedin-search-relevance—people-search