Doctoral Dissertation Research: Improved Skeletal Age-at-Death Estimation and Its Impact on Archaeological Analyses

从骨骼遗骸中估计死亡年龄对于人类寿命、死亡模式、人口增长、疾病经历和太平间做法的考古研究以及失踪人员、犯罪受害者、移民边境死亡和战争罪受害者的医学鉴定至关重要。尽管经过一个多世纪的发展，现有方法得出的成人年龄估计的准确性（估计年龄和实际年龄的对应关系）和精度（年龄间隔长度）不足以达到这些目的。这意味着，由于年龄估计错误，目前对过去种群年龄结构、长期种群趋势、病原体负荷及其对人类宿主的影响以及人类寿命的理解可能存在严重缺陷。为了应对这一紧迫的理论和实践需求，包括乔治·米尔纳博士和他的博士生萨拉·格茨（宾夕法尼亚州立大学）在内的一个国际研究小组正在开发一种方法，在他们早期的统计程序（过渡分析，TA）的基础上，对整个成人寿命进行更准确、精确和公正的骨骼年龄估计。这项正在进行的工作将显著减少年龄估计误差，描述和量化骨骼变异，并改进统计方法。它涉及到一个根本性的转变，从仅用简单的统计来评估少数骨骼特征，到使用复杂的统计方法来分析整个骨骼的特征，以从与年龄相关的骨骼变化中提取尽可能多的信息。该项目将在大量现代已知年龄的欧洲骨骼上验证新扩展的TA方法，然后将该程序应用于两个大型中世纪和早期现代样本，作为考古应用的概念证明。在项目结束时，修订后的TA将作为一个免费的、可下载的、易于使用的程序和插图评分手册分发。数据将被保存并提供给其他研究人员使用。项目PI和Co-PI将通过同行评审的出版物、专业会议演讲、邀请讲座和研讨会来培训学生（本科生和研究生）和专业人员。对许多已知年龄的欧洲骨骼的验证将证明修订后的TA的准确性和精度的提高。这项重点研究是扩大研究团队的第一步。S方法适用于广泛的地理上不同的人群。验证后，来自丹麦霍森斯市的两个城市墓地样本- Ole Worms Gade（公元1100 -1500年）和修道院教堂（公元1500 -1800年）-将用于调查改进年龄估计的潜在影响，以帮助我们了解重要的社会和人口趋势，如移民和成人预期寿命的变化。这个应用程序将演示如何更好的骨骼数据可以弥合考古和历史资源之间的差距。特别是，它将提供关于过去人口特征的信息，这些信息无法通过历史文献或使用标准方法估计年龄的骨骼获得。

Age-at-death estimates from skeletal remains are essential for archaeological studies of human longevity, mortality patterns, population growth, disease experience and mortuary practices, as well as medicolegal identifications of missing persons, crime victims, migrant border deaths, and war-crime victims. Despite over a century of development, the accuracy (estimated and actual age correspondence) and precision (age interval length) of adult age estimates produced by existing methods are insufficient to reach these ends. That means much current understanding of the age-structure of past populations, long-term population trends, pathogen load and its effect on human hosts, and human longevity may be seriously flawed by age-estimation error. In response to this pressing theoretical and practical need, an international research team that includes Dr. George Milner and his doctoral student Sara Getz (Penn State University) are developing a method to produce more accurate, precise, and unbiased skeletal age estimates for the entire adult lifespan, building on their earlier statistical procedure (Transition Analysis, TA). This ongoing work will significantly reduce age-estimation error, describe and quantify skeletal variation, and refine statistical methods. It involves a fundamental shift from assessing only a few skeletal characteristics with simple statistics to analyzing traits throughout the skeleton using sophisticated statistical methods to extract the most information possible from age-related changes in bones. This project will validate the newly expanded TA method on a large number of modern known-age European skeletons, and then apply the procedure to two large medieval and early modern samples as a proof of concept for archaeological applications. At the conclusion of the project, revised TA will be disseminated as a free, downloadable, and easy-to-use program and illustrated scoring manual. Data will be maintained and made available for other researchers' use. The project PI and Co-PI will train students (undergraduate and graduate) and professionals through peer-reviewed publications, professional meeting presentations, and invited lectures and workshops.Validation on numerous known-age European skeletons will demonstrate the increased accuracy and precision of revised TA. This focused study is the first step in expanding the research team?s method to a wide range of geographically diverse populations. After validation, two urban cemetery samples from the Danish city of Horsens - Ole Worms Gade (1100 -1500 CE) and Monastery Church (1500 -1800 CE) - will be used to investigate the potential implications of improved age estimates for our understanding of important social and demographic trends over time, such as changes in migration and adult life expectancy. This application will demonstrate how better skeletal data can bridge the gap between archaeological and historical sources. In particular, it will provide information about the characteristics of past populations that cannot be obtained through historical documents or from skeletons where ages were estimated using standard methods.