1. A method of deriving the degree of association between words and human-applied labels for a body of text, the method comprising: a) collecting a set of documents representative of the kind needed for an application, b) providing for each paragraph and title in the said documents a label which is considered appropriate for that paragraph or title, c) counting the number of occurrences of a first word within a first paragraph of text designated with a first label, d) counting the number of occurrences of said first word within paragraphs of text designated with a label other than first said label, e) computing the ratio of the occurrences in acts (c) and (d), this ratio being taken as the degree of association between said first word and said section, a ratio greater than 1 signifying a greater than normal association, a ratio less than 1 signifying a weaker than normal association, f) repeating acts (c) through (e) for each word within said first paragraph of text.