SYNONYM IDENTIFICATION BASED ON SEARCH QUALITY

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for obtaining one or more first search results that were generated for a search query; determining a score associated with the first search results; revising the search query using a query revision rule; obtaining one or more second search results that were generated for the revised search query; determining a score associated with the second search results; and evaluating the query revision rule by comparing the score associated with the first search results with the score associated with the second search results.