Previously reported clustering of many of the 42 life-change events, contained in the Schedule of Recent Experience questionnaire, was verified by an analysis of another large sample of US Navy subjects. In addition, the stability of the four life-change clusters were investigated as subjects' age and pay grade (rank) were varied. The life-change cluster method, the Iterative Intercolumnar Correlational Analysis described by McQuitty and Clark, and results obtained by this method, are presented in some detail.
Pugh WM, Erickson J, Rubin RT, Gunderson E, Rahe CRH. Cluster Analyses of Life ChangesII. Method and Replication in Navy Subpopulations. Arch Gen Psychiatry. 1971;25(4):333-339. doi:10.1001/archpsyc.1971.01750160045009