Accuracy of metric sex analysis of skeletal remains using Fordisc® based on a recent skull collection

Abstract

It has been generally accepted in skeletal sex determination that the use of metric methods is limited due to the population dependence of the multivariate algorithms. The aim of the study was to verify the applicability of software-based sex estimations outside the reference population group for which discriminant equations have been developed. We examined 98 skulls from recent forensic cases of known age, sex, and Caucasian ancestry from cranium collections in Frankfurt and Mainz (Germany) to determine the accuracy of sex determination using the statistical software solution Fordisc which derives its database and functions from the US American Forensic Database. In a comparison between metric analysis using Fordisc and morphological determination of sex, average accuracy for both sexes was 86 vs 94%, respectively, and males were identified more accurately than females. The ratio of the true test result rate to the false test result rate was not statistically different for the two methodological approaches at a significance level of 0.05 but was statistically different at a level of 0.10 (p=0.06). Possible explanations for this difference comprise different ancestry, age distribution, and socio-economic status compared to the Fordisc reference sample. It is likely that a discriminant function analysis on the basis of more similar European reference samples will lead to more valid and reliable sexing results. The use of Fordisc as a single method for the estimation of sex of recent skeletal remains in Europe cannot be recommended without additional morphological assessment and without a built-in software update based on modern European reference samples.

Sex determination from the foramen magnum: discriminant function analysis in an eighteenth and nineteenth century British sample

“…Another caveat must be to use discriminant functions only on cases that are known to come from the same population from which the functions were derived [11,23,32], except for a population with similar mean values of the variables and expression of sexual dimorphism in the foramen magnum area. Particularly, in forensic cases, only methods developed on documented skeletal samples of known age, sex and ethnicity should be used.…”

Estimation of stature from cranial sutures in a South Indian male population

“…Morphological trait analyses for sexing skeletons are well established, but they may be difficult due to breakage or postmortem damage of the skeletal remains. Ramsthaler et al [29] verified the applicability of software-based sex estimations outside the reference population group for which discriminant equations were developed. Braga and Treil [30] developed a method for estimating the skeletal age of children based on the centroid size of their face and their basicranium, derived from the three-dimensional coordinates of anatomical landmarks and showed that the centroid size of the facial skeleton can be used an age-related variable without any loss of accuracy with increased age, contrary to most of the methods of pediatric age estimation.…”

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

“…An anthropometric investigation comparing cranial and postcranial elements for sex estimation revealed that postcranial skeleton performs better than cranial when using multivariate analysis [36]. Skull measurements were applied on a validation study conducted by Ramsthaler et al [37]. The authors tested USA discriminant functions on a German sample to compare the use of Fordisc data versus morphological assessment.…”