Sequential validation of cluster analytic subtypes of homeless veterans

To identify subgroups within the homeless population, a number of researchers have employed cluster analytic statistical procedures. Although this is an appropriate application of cluster analysis, many studies have not employed important statistical safeguards against arbitrary results. This study demonstrates a cluster analytic procedure—sequential validation—that enhances the replicability, external validity, and cross-validity of cluster solutions. The procedure is applied to a nationwide sample of 745 homeless veterans. After 12 different clustering procedures were subjected to derivation, replication, external validation, and cross-validation phases, a 4-cluster Ward solution emerged as the most sound. Substantively, the clusters were an alcoholic subtype, a psychiatrically impaired subtype, a best functioning subtype, and a multiproblem subtype. The generalizability of these subgroups to other contexts was assessed by comparing them to subgroups identified in other homelessness research. Suggestions were made for improving the quality of cluster analytic research in community psychology.