Patent ID: 8402033

Claim:
A computer implemented method of extracting a set of valid phrases from a plurality of documents, the method comprising: for each document: identifying a plurality of candidate phrases contained in the document, wherein a candidate phrase includes multiple consecutive words that appear in the document; scoring candidate phrases in the document to produce document phrase scores for the candidate phrases for the document, the document phrase scores for a candidate phrase being based on instances of the candidate phrase that appear in the document, wherein scoring a candidate phrase in the document to produce a document phrase score includes: determining for the candidate phrase two or more subphrases within the candidate phrase, wherein a subphrase contains two or more words; and scoring each determined subphrase in the document as a function of the position of the subphrase relative to a sequence of words containing the candidate phrase; for at least one of the candidate phrases: creating, via a processor, a combined score for the candidate phrase based on a plurality of different document phrase scores for the candidate phrase for respective different documents; and determining whether the candidate phrase is a valid phrase based on the combined score for the candidate phrase and based on the document phrase scores for the candidate phrase.