Transition Analysis 3 (TA3)

TA3 is a new approach to adult age-at-death estimation that uses many traits throughout the skeleton that are combined to produce age estimates throughout the entire lifespan. Method development was funded by an NIJ research grant (NIJ 2014-DN-K007). The method is based on over 1,600 skeletons from four modern skeletal collections representing different ancestry groups from around the world. A proof-of-concept investigation for this approach in archaeological settings was the focus of Getz's doctoral dissertation. The trait manual and software is scheduled for release in 2020. Members of the research team are open to providing workshops and training at academic and professional institutions by request. 

Adult Age Estimated From New Skeletal Traits

And Enhanced Computer-Based Transition Analysis

(NIJ 2014-DN-BX-K007) - PI: George Milner, Co-PIs:  Jepser Boldsen & Steve Oulsey 

International Research Team: (From Left to Right)

Peter Tarp, George Milner, Sara Getz, Svenja Weise, Jesper Boldsen, & Steve Ousely

NIJ GRANT ABSTRACT: Accurate and precise age estimates are critical when identifying people represented by skeletal remains. Unfortunately, obtaining such estimates represents one of the greatest challenges that face forensic anthropologists. This project involves 1) skeletal trait definition and the collection of data on their ages of transition, 2) the refinement of a novel mathematical approach to properly handle the resulting age-related information, and 3) programming to produce a computer program that allows forensic practitioners to take advantage of the new skeletal information and analytical procedures. The resulting procedure will produce unbiased estimates of age throughout the adult lifespan, including the elderly that cannot be aged with standard methods. Individualized estimates are based on the array of morphological characteristics observable in each skeleton. Because the procedure relies on bony features distributed throughout the body, age estimates will be possible for incomplete skeletons, which is essential in forensic applications. Uncertainty about age estimates is expressed by age interval lengths.


The NIJ project covers the collection of data from four known-age skeletal samples, the incorporation of old data recharacterized for this project, assessments of observer error in scoring procedures, and validation studies. Procedure development includes identifying ages of transition from early to late morphological stages for many skeletal features, as well as computer programming to produce a program that will be widely available to the forensic community. The NIJ project builds on the principal participants' extensive experience in the osteological, analytical, and computer programming phases of the planned work. In fact, the NIJ project can be viewed as the capstone of many years of research by project participants focusing on age estimation (almost two decades for two team members). In essence, the research team's demonstrated success with experience-based estimates of known-age skeletons from three continents will be distilled into a quantitative procedure that can be accessed through a user friendly computer program. The results should approximate the success of our prior work that has demonstrated the importance of a much broader array of characteristics than osteologists routinely examine.


Once the NIJ project is completed, users of the procedure will only have to score anatomical features and enter them into the program to obtain results presented in numerical and graphical form suitable for specialist and non-specialist audiences. Project participants will publish articles and present papers and workshops on the procedure and the interpretation of results.​​

TA3 Training Workshops 

Members of the research team are open to providing workshops and training at academic and professional institutions.


The schedule shown here is an example of a workshop offered by Getz split over two days at an academic institution for 15-20 individuals. Single day or multi-hour workshops, as well as short 1-hr intro sessions can be accommodated.


Contact Dr. Sara Getz (

for more information.