Reconsidering the Age-Informative Value of the Pubic Symphysis

Abstract

Estimated age at death is a critical component of the skeletal biological profile for both forensic and archaeological applications. For adults, the pubic symphysis has long been regarded as the most useful feature for age estimation. This study compares the age-informative value of the pubic symphysis as captured by phase methods (Brooks & Suchey 1990; Hartnett 2010) and individual components, to the large suite of Transition Analysis 3 (TA3) traits distributed throughout the skeleton (Milner et al. 2019). Logistic regression curves (i.e., transition curves) are used to visualize where in the life span different skeletal features provide information and are interpreted to understand the features’ individual and collective age-informative value. A total of 309 individuals (217 males, 92 females) with documented ages at death between 15 and 96 years from the Santiago Subactual Osteology Collection (SSOC) were evaluated. Consistent with published literature, the pubic symphysis age-related information is concentrated in the first half of the life span. In contrast, the TA3 traits collectively provide age-informative data for the entire adult age life span. This is the first published study to characterize the collective age-informative value of the binary and ordinal TA3 traits in an independent sample. These data further support a shift toward the identification, evaluation, and use of a wider array of traits throughout the skeleton as a path toward more informative adult age estimates.