Abstract:
Pattern expressions of morphoscopic cranial traits
vary across populations with classification accuracies being
highly dependent on the reference collection to which unknown
skulls are compared. Despite recent developments in populationspecific
standards for South Africans, researchers have not addressed
the accuracy of morphological methods. Several studies
demonstrate differences in sexual dimorphism between South
Africans and North Americans, warranting a need to re-evaluate
sex estimation methods in South Africa. The purposes of this
study were to test the reliability and accuracy of the Walker
(2008) method and to examine patterns of sexual dimorphism
among South Africans. A total of 245 modern Black and White
South African male and female crania from the Pretoria Bone
Collection, University of Pretoria, were scored using theWalker
(2008) methodology. Cohen’s kappa was used to evaluate reliability
of the method, and percent correct assessed validity of the
method. Logistic regression was utilised to create modified
population-specific formulae. Inter- and intra-observer agreement
was moderate to excellent (0.60–0.90), except for the
mental eminence (0.40). The percent correct results for sex were
80%or higher for combinations of glabella,mastoid andmenton
and between 68 % and 73 % for menton, mastoid, orbital
and nuchal margin using logistic equations of Walker
(2008). White males had the highest (94–97 %) and
White females had the lowest (31–62 %) percent correct. The low accuracies obtained when using Walker’s
(2008) equations emphasised the need for population-specific
sex estimation models. Modified formulae for South Africans
were created, yielding higher classification rates (84–93 %)
than when North American standards were employed.
