Comparison of Four Skeletal Methods for the Estimation of Age at Death on White and Black Adults^*

Abstract

When analyzing human adult skeletal remains, it is often difficult to decide whether a single aging method will give a more reliable age estimation than a combination of methods. This study evaluates four macroscopic indicators for age estimation on 218 American White and Black individuals, ranging in age from 25 to 90 years of age, from the Terry collection. Individuals in the sample were selected to have a balanced race, sex, and age distribution. The following aging methods were applied to each skeleton by one experienced observer: the Suchey-Brooks (SB) pubic symphysis method, the Lovejoy auricular surface method, the monoradicular teeth Lamendin (LM) method, and the Işcan (IC) method for fourth ribs. The statistical study involved the evaluation of inaccuracy and bias (based on median age) for each age indicator and the combination of methods using Principal component analysis (PCA). Analysis was performed on the entire sample, then by race, then sex, and then age group (25-40 years, 41-60 years, and >60 years). PCA was the most accurate method for both racial groups when all age groups are analyzed together. When the sample was divided into age groups, SB was the most accurate for young adults (25-40 years) and LM was the most accurate for middle adults (41-60 years). After the age of 60, all methods are highly inaccurate, although IC gives the lowest inaccuracy. As regards bias, the study highlights the tendency of all methods to overestimate the age of young individuals and to underestimate in the older age group. No single skeletal indicator of age at death is ever likely to reflect accurately the many factors that accumulate with chronological age. In fact, one must use as many dental and skeletal indicators as possible. However, in order to maximize the potential of each method, in the final evaluation one should consider mainly the method or methods that have a higher accuracy for a particular age range.

A comparison of three established age estimation methods on an adult Spanish sample

“…Both bias and absolute error are good indicators of at method's inaccuracy [26]. Bias is the statistical measure that identifies the direction of the committed error in a method's misclassification [2,5,10,25,21] -whether the estimated age is over-or underestimated. If the estimated age is older than the chronological age then the bias is positive.…”

“…Absolute error is the statistical measure that evaluates the degree of the committed error in a method's misclassification [2,5,10,25,21]. Absolute error was calculated as the average absolute difference between estimated age and chronological age using each method (Σ|estimated age -chronological age|/ n).…”

“…The key to the successful application of a particular method is an understanding of whether the method is accurate (correct), precise (refined), and repeatable from an intra-and interobserver standpoint when applied to unknown individuals outside of the original reference sample [e.g. [4][5][6][7][8]. However, the reference samples on which many of the original methods were based are among very few known age-at-death collections of sufficient sample size for testing purposes [9][10][11].…”

A test of the Lamendin method of age estimation in South African canines

“…Subsequent testing of the method or modifications thereof could mostly not demonstrate the same success rates [5,[42][43][44][45]. In general, it was found to be more accurate in the middle to older age groups and root transparency had a better correlation with age than periodontal recession.…”

“…In general, it was found to be more accurate in the middle to older age groups and root transparency had a better correlation with age than periodontal recession. As is the case with most age estimation techniques, age of older individuals tends to be underestimated, and those of younger individuals overestimated [43]. Post-mortem factors may also influence the results [46].…”