1. A method for determining a quality for a data clustering, said data clustering resulting in a plurality of clusters each cluster having a cluster identifier, the method comprising the steps of: determining a set of observed values for at least one of the clusters by mapping the cluster identifier of said one of the clusters to a first predefined value and by mapping the cluster identifiers of other clusters to a second predefined value, and calculating a normalized statistical coefficient based on the set of observed values to determine the quality for said one of the clusters.