Auricular surface aging: a blind test of the revised method on historic Italians from Sardinia

Age determination from human skeletal remains is an important biological parameter in both forensic and bioarchaeological contexts. This study presents the results of a blind test of the revised auricular surface age estimation method proposed by Buckberry and Chamberlain (Am. J. Phys. Anthropol. 119 (2002) 321-329) on a large sample (n=404) of known sex and age from the Sassari collection, housed at the Museum of Anthropology, University of Bologna, Italy. Ilia were scored for five features: transverse organization, surface texture, microporosity, macroporosity, and apical changes, which combined for a composite score. The results indicated that all features and the composite score were positively correlated with known age. Composite scores were significantly different between the sexes, suggesting that males and females should be treated separately. Bias and inaccuracy varied across age intervals. Age tended to be overestimated in individuals under age 59 and underestimated for those over age 60 years. However, the revised method showed improvement over the original auricular surface method (Lovejoy et al., Am. J. Phys. Anthropol. 68 (1985) 15-28), especially for aging older individuals. Considerable variation exists in the age ranges derived from composite scores and few significant differences were found between age stages, suggesting that fewer stages with wider age ranges may be necessary. The independent, quantitative scoring of the surface features makes the revised method substantially easier to apply and the method shows significant improvement for aging older individuals.     

New Approaches to Age Estimation Using Palatal Suture Fusion

Palatal suture fusion has seen little testing and/or application due in part to an inadequately described relationship to formal age ranges. This study presents a modified scoring method that examines fusion on samples of modern documented adult males and compares two Bayesian approaches to age estimation. In the first analysis, American and Portuguese collections were used to derive univariate and multivariate transition analysis (TA) parameters, which combined with an informative prior, estimated age in a sample of modern Americans and Portuguese. For the second analysis, a Bayesian multiple linear regression (BMLR) used indicator statuses as the independent variables with age as the dependent variable. Highest posterior density regions (HPDRs) and highest posterior density intervals (HDI) were calculated for a holdout sample. Final age estimates for the methods were tested for accuracy using cumulative binomial tests at 75% and 90% coverages. The HPDRs from multivariate TA captured age better for younger individuals, but consistently underaged. The cumulative binomial tests on the BMLR results indicated the prediction intervals performed as expected, and we show they are narrower (more precise) and/or more accurate than the corresponding HPDR. The modified method presented here formally links palatal suture obliteration to age using two different approaches, one of which (BMLR) is new to the aging literature. The BMLR provided results free from bias and more reasonable age ranges while maintaining accuracy. We present a look-up table and a free, simple R file for users to download and run their own estimates with BMLR.     

Age estimation from the human os coxa: a test on a documented Italian collection*

Current standards for age at death estimation from the pelvis are based on Americans of European and African ancestry. Our limited understanding of population variability hampers our efforts to apply these techniques to the various skeletal populations around the world, especially in global forensic contexts. However, documented skeletal samples are rare, limiting our ability to test our techniques. This study tested the Suchey-Brooks pubic symphysis aging method and the auricular surface method originally developed by Lovejoy et al. on a large sample (n = 404) of known sex and age from the Sassari Collection, housed at the Museum of Anthropology at the University of Bologna, Italy. The results indicate that for both methods, bias and inaccuracy increased with age and actual age tended to be underestimated over the age of 40. The auricular surface method performed slightly better, exhibiting slightly lower levels of bias and inaccuracy, especially for males.     

Auricular Surface Aging: Comparing Two Methods that Assess Morphological Change in the Ilium with Bayesian Analyses

Modern standards in forensic anthropology require rigorous testing and evaluation of methods used for aging skeletal remains. Age estimation has been criticized for bias, inaccuracy, and population specificity; issues which are minimized by the application of Bayesian methodology. Using Bayesian statistics, we compare the Lovejoy et al. (Am J Phys Anthropol, 68, 1985, 15) (original) and Buckberry and Chamberlain (Am J Phys Anthropol, 119, 2002, 231) (revised) auricular surface aging methods. Transition analysis parameters derived from American males (n = 372), in combination with a Thai male (N = 37) informative prior, statistically model age in Portuguese males (n = 221). Cumulative binomial tests assess the accuracy of the generated age ranges. Overall, the application of transition analysis and Bayesian statistics significantly improved age estimation with both methods (also outperforming Suchey‐Brooks pubic symphysis aging). Moreover, the accuracy of the original method was low without statistical modeling, whereas the revised method can be applied accurately without further statistical analysis. Additionally, reference tables for aging Portuguese males are provided.