Disregarding population specificity: its influence on the sex assessment methods from the tibia

Abstract

Forensic anthropology has developed classification techniques for sex estimation of unknown skeletal remains, for example population-specific discriminant function analyses. These methods were designed for populations that lived mostly in the late nineteenth and twentieth centuries. Their level of reliability or misclassification is important for practical use in today's forensic practice; it is, however, unknown. We addressed the question of what the likelihood of errors would be if population specificity of discriminant functions of the tibia were disregarded. Moreover, five classification functions in a Czech sample were proposed (accuracies 82.1-87.5 %, sex bias ranged from -1.3 to -5.4 %). We measured ten variables traditionally used for sex assessment of the tibia on a sample of 30 male and 26 female models from recent Czech population. To estimate the classification accuracy and error (misclassification) rates ignoring population specificity, we selected published classification functions of tibia for the Portuguese, south European, and the North American populations. These functions were applied on the dimensions of the Czech population. Comparing the classification success of the reference and the tested Czech sample showed that females from Czech population were significantly overestimated and mostly misclassified as males. Overall accuracy of sex assessment significantly decreased (53.6-69.7 %), sex bias -29.4-100 %, which is most probably caused by secular trend and the generally high variability of body size. Results indicate that the discriminant functions, developed for skeletal series representing geographically and chronologically diverse populations, are not applicable in current forensic investigations. Finally, implications and recommendations for future research are discussed.

Sex estimation of os coxae using DSP2 software: A validation study of a Greek sample

“…Amongst the basic biological features sex is the most studied with several methods marking high accuracies [1][2][3]. Scholars agree that most osteometric methods are population specific [4][5][6] with the exception of the pelvis [1,7]. Female pelvis is constructed to facilitate both bipedalism and parturition, thus the shape is notably different compared to the male pelvis.…”

Sex estimation of the tibia in modern Turkish: A computed tomography study

“…In addition, new research supports that several postcranial elements are actually better indicators of sex compared to the cranium [2]. In this vein, many population-specific studies have investigated the utility of the tibia as an indicator of sex and the accuracy of sex estimation when using the tibia as assessed by several morphometric parameters is over 84% [6][7][8][9][10][11][12][13][14][15][16][17] According to the religion of Islam, when a person dies, the first stage of the afterlife starts in the grave. Therefore, the use of dead bodies for scientific study purposes other than legal obligations is often impossible.…”

“…It has been used to produce population specific formulae for several different skeletal elements, including the tibia. Indeed, osteometric studies for sex estimation from the tibia have been conducted for several populations such as Northern Americans [11,12], medieval and modern Croatians [13,14] Portuguese [15], Southern Europeans [4], Czech [16] and Greek-Cypriots [17]. The high classification results (up to 95%) achieved in the abovementioned studies clearly makes the tibia a very successful sex indicator.…”

Accuracy and reliability of Southern European standards for the tibia: a test of two Mediterranean populations

“…It was recommended the application of both methods due to low average accuracy obtained from the metric approach. Low classification accuracy was also noted in another study [38] European and North Americans were applied to a Czech sample. This study reported high misclassification of females and up to 100% sex bias.…”