The accuracy of age estimation using transition analysis in the Hamann-Todd collection

Objectives: Reconstructing demography of past populations using skeletal data is challenging when analyzing adults because the process of biological aging does not always reflect the individual's chronological age. A proposed solution to address the limitations of traditional age estimation methods is transition analysis (TA), a multifactorial method of age estimation. However, despite its methodological refinement, TA has varying degrees of accuracy when applied to different known-age skeletal samples. This study assesses TA's accuracy by comparing age estimates to known age at death in the Hamann-Todd Collection.

Materials and methods: We contrasted the maximum likelihood age estimates generated by the ADBOU program to the known ages of 221 individuals. The absolute error was calculated for the entire sample, and compared between sex and ancestry.

Results: The mean absolute error in the sample is 11.6 (SD = 10.3) years, with white individuals' errors (14.1 years) being significantly higher than black individuals' (9.1 years; p < 0.001). No significant differences were found between sexes (p = 0.621). A weak to moderate positive correlation was found between known age and absolute error for white males (R = 0.607; p < 0.001), white females (R = 0.509; p < 0.001), and black males (R = 0.371; p = 0.006). The accuracy of TA age estimates varied when each anatomical region was analyzed independently, but the combination of all three anatomical regions yielded the most accurate age estimates.

Discussion: These findings further support that TA accuracy depends on the prior distribution used and, in the Hamann-Todd Collection, the accuracy for white individuals is more influenced by this limitation than when black individuals are analyzed.