Nov 18, 2009

The mean measure of divergence: its utility in model-free and model-bound analyses relative to the Mahalanobis D(2) distance for nonmetric traits

American Journal of Human Biology : the Official Journal of the Human Biology Council
Joel D Irish


The mean measure of divergence (MMD) distance statistic has been used by researchers for nearly 50 years to assess inter-sample phenetic affinity. Its widespread and often successful use is well documented, especially in the study of cranial and dental nonmetric traits. However, the statistic has accumulated some undesired mathematical baggage through the years from various workers in their attempts to improve or alter its performance. Others may not fully understand how to apply the MMD or interpret its output, whereas some described a number of perceived shortcomings. As a result, the statistic and its sometimes flawed application(s) have taken several well-aimed hits; a few researchers even argued that it should no longer be utilized or, at least, that its use be reevaluated. The objective of this report is to support the MMD, and in the process: (1) provide a brief history of the statistic, (2) review its attributes and applicability relative to the often-used Mahalanobis D(2) statistic for nonmetric traits, (3) compare results from MMD and D(2) model-free analyses of previously-recorded sub-Saharan African dental samples, and (4) investigate its utility for model-bound analyses. In the latter instance, the ability of the D...Continue Reading

  • References49
  • Citations18


Mentioned in this Paper

African Continental Ancestry Group
Sample Fixation
Data Interpretation, Statistical
Bone Structure of Cranium
Two-Parameter Models
Biological Evolution
Rasmussen Johnsen Thomsen Syndrome
Cranial Nerve Diseases
EAF2 gene

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