1. A computer-implemented method for creating a cluster structure from a data set containing a plurality of input variables, comprising: creating global clusters, within a first stage, by computing a similarity matrix from the data set; creating, within a second stage, both a global cluster structure and a sub-cluster structure; wherein the global cluster structure and the sub-cluster structure are created using a latent variable clustering technique; and forming, as output to a computer-readable data store, the cluster structure by combining the created global cluster structure and the created sub-cluster structure.