1. A computer implemented method of analyzing and graphically representing the correlation of a plurality of transaction items, the method comprising the steps of: retrieving data associated with groups of the transaction items, correlating the groups of transaction items in a dimensionally reduced manner using the retrieved data, graphically representing the correlated groups of transaction items, creating a tree hierarchy using the retrieved data, wherein the tree hierarchy classifies the groups of transaction items in a hierarchy according to a defined user understandable factor, graphically representing the tree hierarchy i) as an overlay over the top of the correlated groups of transactions, and ii) as a textual tree hierarchy, wherein each of the graphical representations of the tree hierarchy is linked to the correlated groups of transaction items, and graphically representing an interaction between the correlated groups of transaction items and the linked tree hierarchy by i) detecting a selection of one of the overlay, textual tree hierarchy and a correlated group of transaction items and ii) graphically representing how the overlay, textual tree hierarchy and correlated groups of transaction items are linked.