Osteometric sex determination from the pelvis—Does population specificity matter?

Abstract

Sex determination from unknown skeletal remains is of vital importance in forensic anthropology, and much research has been conducted in this field. One of the most commonly used methods is to create discriminant function formulae from metric data. It is widely argued in the literature that these formulae are population-specific, as various populations differ with regard to general body size and degree of sexual dimorphism. However, the population of origin may not always be known, and formulae do not exist for all possible population groups. The aim of this study was to assess whether it is really necessary to develop population-specific formulae for pelvic measurements. For this purpose, skeletons from three different populations namely Greeks living on Crete (n=193), South African whites (n=200) and South African blacks (n=199) were used. Seven standard measurements from the innominate bone were employed and discriminant function formulae developed for each population separately, and then for all three populations combined. Classification accuracies indicate that very little is gained by keeping the populations separate. For example, in a stepwise calculation using all measurements the overall classification accuracy was 94.5% for the combined group, and 94.8%, 94.5% and 94.5% for the Greeks, SA whites and SA blacks respectively. In a direct analysis using pubic and ischial length, the overall combined accuracy was 89.8%, versus 89.3%, 90.0% and 89.0% for the three separate groups. When only the acetabular diameter was used, the corresponding figures were 82.5% versus 84.1%, 81.6% and 83.5%. These results indicate that population-specific formulae may not be necessary for pelvic data, but it should be kept in mind that the pelvis is highly dimorphic. More research is needed, also including other bones of the skeleton.