An Interactive Morphological Database for Estimating Sex in Modern Adults

As submitted by the proposer: Estimating an unidentified person’s biological profile (age, sex, ancestry, stature) from their skeletal remains is a vital component of the forensic anthropologist’s role in medico-legal investigations and is necessary to narrow the list of potential victims. Sex estimation is the most important aspect of this profile because it essentially reduces the list by half, as the results are limited to two options: male or female. An incorrect sex assessment would greatly hinder positive identification of the unknown individual; therefore, it is imperative that the methods used for sex estimation are reliable and valid. Morphological methods of sex estimation have focused on the differences between sexes in cranial and pelvic morphology. Two newer methods were recently developed to incorporate the most popular cranial and pelvic morphological traits into a statistical framework for classification that includes a standardized ordinal scoring scheme. The Walker (2008) method uses glabella, mental eminence, mastoid process, supra-orbital margin, and the nuchal crest of the crania, while the Klales et al. (2012) method uses the ventral arc, subpubic contour, the medial aspect of the ischio-pubic ramus of the pelvis. These eight traits are the most popular traits for sex estimation and they are used by most practitioners for sex estimation (Klales 2013). They continue to be popular due to the high reliance and preference by practitioners on morphological methods. Both of these methods are currently being used and cited in active forensic cases reports throughout the United States, as well as internationally. In light of the Daubert (Daubert vs. Merrell Dow Pharmaceuticals, Inc. 1993) criteria and the National Academy of Sciences (2008) report, the methods of Walker and Klales and colleagues needs to be tested for validity and reliability in light of secular change, population variation, and asymmetry in trait expression. The goal of this project is to do just that, by examining these traits from samples originating from diverse temporal and population groups. Both observer error in scoring and asymmetry and its impact on sex classification will also be explored. The culmination of this research will be the creation of a free, interactive computer program for morphological sex estimation that can be used by forensic practitioners for active forensic casework. Forensic scientists will be able to score the eight cranial and pelvic traits in their unknown individual and then use the temporal and population specific equations to predict sex membership with concordant posterior probabilities and accuracy rates. This project contains a research and/or development component, as defined in applicable law. ca/ncf