A MONTE CARLO STUDY OF THE ACCURACY OF A HIERARCHICAL GROUPING PROCEDURE.

The accuracy of the Ward-Hook method of hierarchical grouping was studied using artificial data sampled from a mixture distribution. The expected number of sample misclassifications as well as the variance of these mimlassifications were taken as the criteria of subgrouping accuracy. It was found that the expected sample misclassificatiun rate was a positively biased estimator of the population probability of misclassifioartion. Further, by in- c d n g sample size, the variance of the sample misclassifications decreased. Accurate subgroupings were found in geneml when the population misclassification rake was very low (.02). When this probability was increased to .20, the misclassification variance increased sharply, unless sample size was large.