US Patent 9229974 Classifying queries

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for classifying queries. A query that includes one or more query terms is received. One or more entity identifiers are extracted from one or more search results that are responsive to the query. One or more of the query terms are compared with the extracted entity identifiers. Based on comparing the query terms with the extracted entity identifiers, the query is classified as an entity-triggering query or as a description-triggering query.