Sex and ancestry estimation in South Africans from measurements of the calcaneus and talus-a validation study

Forensic anthropological methodology needs to continuously be tested and validated to remain on par with international standards of best practice. The present study aimed to validate previously published metric and non-metric methods for estimating sex and population affinity from the calcaneus and talus in black and white South Africans. The calcanei and tali of two-hundred individuals, equally distributed by sex and population, were measured and the validity of the discriminant functions were assessed. Only some functions estimating sex using both skeletal elements and estimating population affinity using the calcaneus are valid, with present and original accuracies not differing significantly (p > 0.05). Population affinity estimation functions using the talus, however, are not valid. Functions yielding accuracies in the present study between 50.00% and 74.00% should not be used as these rates are only slightly above chance (50.00%), but functions yielding accuracies of 75.00% and above may be considered for use in forensic casework. Almost all functions yielded accuracies significantly lower (p < 0.05) for females and for black individuals compared to their male and white counterparts, respectively. As a result, the classification of individuals as female or as black should particularly be interpreted with caution. This study also assessed the validity of previously described morphological methods used to estimate population affinity using the calcaneus. The number of talar articular facets present differs significantly between population groups and the validity of this method was therefore confirmed. These methods should be further validated using more modern skeletal collections or living individuals using various virtual methodologies.