8. The method of claim 1 , where the expected co-occurrence rate of the related phrase and the first phrase is a function of a number of documents in the document collection that include the first phrase and a number of documents in the document collection that include the related phrase, and the actual co-occurrence rate being a function of a number of times the first phrase appears within a threshold number of words of the related phrase in the document collection.
8. The method of claim 1 , where the expected co-occurrence rate of the related phrase and the first phrase is a function of a number of documents in the document collection that include the first phrase and a number of documents in the document collection that include the related phrase, and the actual co-occurrence rate being a function of a number of times the first phrase appears within a threshold number of words of the related phrase in the document collection. 9. The method of claim 8 , wherein the threshold is about 100.