The Inappropriateness of the Correlation Coefficient as a Measure of Taxonomic Resemblance

three operational taxonomic units (OTU's): C, E, and G. The characters are presumed to be standardized and entirely independent of each other (i.e., not biased by a common factor such as size). C and E are taken from Sokal and Sneath (1963:296) with characters 5 and 6 omitted because there was no comparison for these characters. G and C are identical except for character 2. C agrees with E in character 2, but G does not. Therefore, the resemblance between C and E is obviously greater than the resemblance between E and G. However, the correlation coefficients (r) would suggest the reverse, being 0.882 for the former and 0.922 for the latter. Table 2 shows characters (also presumed to be standardized and independent) of OTU's H, I, and J. The differences between H and I and