1. A method of analyzing the relationship of events according to a taxonomic structure having separate predefined layers in a hierarchical classification system comprising the steps of: determining the frequency distribution of the events with respect to the classification system; and, distributing the frequency distribution to all layers of the taxonomic structure so that each layer reflects the frequency of events below it; and, normalizing and weighting the frequency distribution with respect to all events either unary or binary or both; and, determining a discriminate function which may take the form of a linear or non-linear combination of values useful in creating an association index.