This document reports on a project with the objective of quantifying the impact of intrinsic and extrinsic covariates on juvenile age estimation and assessing differences between global and country-specific age estimation models for forensic application; the report lays out a summary of the project, participants and other collaborators, changes in approach from original design, accomplishments, results, and findings, artifacts resulting from the research, and references cited.
The author describes a research project that had the objective of quantifying the impact of intrinsic and extrinsic covariates on juvenile age estimation and assessing differences between global and country-specific age estimation models for forensic application through the use of a large, diverse, international sample of children, ages zero to 15 years. The research had two specific aims: analyze the relationship between skeletal growth and development markers and age in different populations and evaluate the influence of several covariates on those markers; and explore a global model for age estimation and quantify the impact of country-level socio-economic status (SES), inferred by the country’s Human Development Index (HDI), and wealth inequality, inferred by the country’s Gini coefficient, for all age indicators and covariates. Results demonstrated the following: diaphyseal dimensions yielded low intra-observer and inter-observer errors as did vertebral neural canal measurements on virtual surfaces, which confirmed that the data acquired from different imaging modalities could be pooled for researcher analysis; scatterplots revealed diaphyseal lengths had greater consistency among countries compared to diaphyseal breadths; population differences in growth trajectories are more apparent from childhood onwards; sex differences were observed for proximal and distal long bone breadths; dental developmental stages have comparable ranges for chronological ages for all countries, and when there were sex differences in dental development, females were more advanced than males; and some sexual dimorphism was also apparent in the timing of epiphyseal fusion of the secondary ossification centers corresponding to the proximal distal long bone epiphyses, the acetabular epiphysis, and the calcaneal tuberosity. The author also reports on other results related to the structural equation modeling (SEM), multivariate variation in growth and in development, vertebral neural canals, global versus population-specific age estimation models, and the application of the global Mixed Cumulative Prohibit (MCP) models.