Development of Modern Subadult Standards: Improved Age and Sex Estimation in U.S.Forensic Practice

As submitted by the proposer: Forensic anthropologists are routinely asked by coroners, medico-legal professionals, and law enforcement agencies to estimate a biological profile (i.e., age, sex, stature and ancestry) from a set of unidentified skeletal remains. In contrast to the abundance of collections and techniques associated with adult skeletal material, there is a paucity of modern, known subadult skeletal material, which affects the creation and validation of appropriate forensic standards. Forensic anthropologists generally rely on a few outdated methods that were devised using historical and relatively small sample sizes. Given documented secular changes in the growth and development of children, antiquated methods are not appropriate to apply to modern subadult individuals in the medico-legal setting. Although recently developed radiographic databases attempt to mitigate the issues of sample size and modernity, conventional X-rays present some major limitations in terms of magnification, distortion, and 2D superimposition of anatomical structures. These limitations have hindered the development of new subadult standards. The aim of this project is to use multi-slice computed tomography (MSCT) data from a large, diverse sample of modern subadults to develop new univariate and multivariate methods to estimate subadult age and sex for practical forensic applications. The proposed research sample will consist of over 2,500 MSCT scans of modern subadult individuals (aged birth to 25 years) obtained from two U.S. medical examiner’s offices and from Australian clinical data. Epiphyseal union scoring (long bones, pelvis, and spheno-occipital synchondrosis) and osteometric data from the long bones will be used to develop modern subadult age estimation standards. Geometric morphometric analyses on the subadult pelvic elements and osteometric data from the long bones will be used to develop modern subadult sex estimation standards. Univariate, multivariate, and Bayesian statistical approaches will be utilized for all estimation techniques and will be accompanied by error rates, as necessitated by the Daubert ruling and the recent National Academy of Sciences report. This project will result in modern, statistically rigorous standards for skeletal age and sex estimation in subadults. The large and diverse sample reflects the demographics and subsequently captures the variation associated with growth and allows for tests of regional differences, so that the most appropriate standards can be presented. The research and methods developed in this project will be applicable to dry bone specimens, MSCT scans, and radiographic images, thus providing tools for forensic practitioners in a variety of settings. This project contains a research and/or development component, as defined in applicable law. ca/ncf