ON THE METHODS AND THEORY OF CLUSTERING

The need for methods of clustering individuals into homogeneous groups seems clear. One hopes, by applying them to his data, to discover clusterings which may prove to be important. This aim appears straightforward, but the methods which exist do not necessarily satisfy them. The procedures which employ the correlation measure of profile similarity, and those which employ the distance measure are discussed. Technical and logical problems are shown to exist for both measures. The key defect in almost all clustering procedures seems to be the absence of a statistical model. The suggestion is made that the clustering problem be stated as a mixture problem. The need for further work by psychologists and statisticians is pointed out.