A Bayesian Approach to Estimating Age from the Auricular Surface of the Ilium in Modern American Skeletal Samples

Abstract

Age estimation from human skeletal remains is a critical component of the biological profile for unidentified decedents. Using a Bayesian approach, we examine two popular methods (Lovejoy–LJ, and Buckberry zand Chamberlain–BC) for estimating age from the auricular surface of the ilium. Ages of transition are generated from a modern Portuguese skeletal sample (n = 466) and are coupled with an informative prior from historic Spitalfields, London (n = 179) to estimate age in a sample of modern Americans from the Bass Donated collection (n = 639). The Bass collection was challenging to statistically model, potentially due to higher morbidity and mortality characteristics of the central southern United States. The highest posterior density ranges provide a realized accuracy between 84–89% for males and 85–91% for females using the LJ method, and a realized accuracy between 79–82% for males and 65–71% for females using the BC method. Both methods worked well for older individuals. Cumulative binomials showed that both methods significantly underperformed; however, results were better for the LJ method, which also showed lower bias. Reference tables for aging modern American samples are provided, and the data meet Daubert guidelines, i.e., legal criteria for acceptable scientific evidence in a court of law in the United States.