12. A computer-implemented method comprising: extracting, by a processor, text from a document; identifying, by the processor, terms within the extracted text, each of the terms comprising a contiguous grouping of two or more tokens, each token comprising a word; determining, by the processor, a standard deviation of offset or gap for each of the terms using positions of individual occurrences of each of the terms in the document; and ranking the terms using the standard deviation of offset or gap for each of the terms.
16. The method of claim 12 further comprising: providing a listing of ranked terms; receiving designations of terms from the listing to be associated with the document as one or more keywords; and associating the one or more keywords with the document.