US Patent 9514156 System and method for topic extraction and opinion mining

Techniques for topic extraction and opinion mining are described. For example, a machine selects a document that is pertinent to a topic based on searching a plurality of documents. The machine identifies an identifier of a party to a transaction being referenced in the document, and identifies the transaction conducted by the party to the transaction based on the document. The machine determines a rating of the transaction based on the document. The determining of the rating of the transaction includes identifying, from a plurality of polarity words included in the document, a dominant polarity word based on a syntactic distance between the dominant polarity word and the topic in a syntactic tree. The machine determines a sentiment of the document based on the transaction, and the rating of the transaction.