Sex Estimation in Forensic Anthropology: Taking a Legally-Informed Approach to Method Development

法医人类学的目标是协助法医调查，通常涉及腐烂或骨骼遗骸。当遗骸属于一个身份不明的死者时，第一步是建立一个“生物侧写”，其中性别估计是一个关键组成部分。当使用度量（例如，骨头的长度）和形态（例如，骨头的形状）数据以及评估多个骨骼元素时，性别估计的准确性会增加。目前还没有同时满足这两个标准的性别估计方法。法医人类学家经常被要求在法律诉讼中作证并提供专家证据；然而，当这些证据的可采性受到质疑时，法医人类学领域缺乏对如何评估性别估计方法的评估，导致法医人类学家应该使用哪些方法以及如何开发改进方法的指导很少。目前，在美国国家失踪和身份不明人员系统中，有13885人被列为“身份不明”，其中796人的性别被列为“不确定”。这项研究将产生一种新的性别估计方法，既符合法律的可采性标准，又能适应广泛的遗骸（例如，只有头骨与完整的骨架），最终目标是减少美国身份不明的尸体数量。该项目将把来自多个骨骼元素的度量和形态学数据结合到一个单一的预测模型中，该模型将满足证据挑战期间的关键法律考虑，同时提高准确性和可靠性。将创建一个方法开发框架，其中包括(1)关于专家证人证据可采性的法律观点和(2)关于性别估计方法的法医人类学观点，以减少采用新方法的障碍。使用这个框架，骨骼数据将被收集并整合到一个预测模型中，使用新的混合累积概率算法，并将作为一个免费的、开放访问的基于网络的图形用户界面传播给所有法医人类学家。这种创新的方法将产生一种单一的、统计上有效的性别估计方法，可以适应连续和有序数据、条件依赖、异方差和缺失数据，因此在绝大多数法医人类学案例中都可以使用。通过使用法律可采性标准作为指导方针，由此产生的模型也将对证据挑战具有鲁棒性。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The goal of forensic anthropology is to assist in medicolegal investigations, typically involving decomposed or skeletal remains. When the remains belong to an unidentified decedent, the first step is to construct a “biological profile,” in which the estimation of sex is a crucial component. Accuracy in sex estimation increases when both metric (e.g., the length of a bone) and morphological (e.g., the shape of a bone) data are used and when multiple skeletal elements are assessed. There are currently no methods for sex estimation that meet both of these criteria. Forensic anthropologists are often called upon to testify in legal proceedings and provide expert evidence; however, the field of forensic anthropology lacks an assessment of how sex estimation methods have been evaluated when the admissibility of such evidence is challenged, resulting in little guidance on which methods forensic anthropologists should use and how to develop improved methods. There are currently 13,885 individuals listed as “unidentified” in the National Missing and Unidentified Persons System, including 796 individuals for whom sex is listed as “unsure.” This research will produce a new method for sex estimation that meets legal admissibility standards and additionally can accommodate the wide range of remains that are recovered (e.g., only a skull versus a complete skeleton), with the ultimate goal of reducing the number of unidentified bodies in the United States.This project will combine metric and morphological data from multiple skeletal elements into a single prediction model that will satisfy key legal considerations during evidentiary challenges, while improving accuracy and reliability. A framework for method development will be created that incorporates (1) legal perspectives on the admissibility of expert witness evidence and (2) forensic anthropology perspectives on methods of sex estimation to reduce barriers for adopting a new method. Using this framework, skeletal data will be collected and integrated into a prediction model, using the novel Mixed Cumulative Probit algorithm, and will be disseminated as a free, open-access web-based graphical user interface available to all forensic anthropologists. This innovative approach will result in a single, statistically valid sex estimation method that can accommodate both continuous and ordinal data, conditional dependence, heteroskedasticity, and missing data and therefore be used in the vast majority of forensic anthropology casework. By using legal admissibility criteria as guidelines, the resulting model will also be robust to evidentiary challenges.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.