The Composite Method: A Novel, Continuum-Based Approach to Estimating Age from the Female Pubic Symphysis with Particular Relevance to Mature Adults

Abstract

While a myriad of effective techniques exist to aid in symphyseal age estimation for those 40 years and younger, few offer similar levels of efficacy for those beyond that threshold. Through the application of a novel technique, this study sought to determine whether a closer inspection of degenerative change may help to improve precision in age estimation for post-epiphyseal adults. Results show that the combination of five distinct areas of interest, plus a correction for density, accurately estimated age 87.75% of the time (averaged amongst four observers [spread: 72–100%]) for a subset of 50 living British females. An adjusted R2 value of 0.85, an RSME value of 5.62 years, and a PCC value of 0.92 also confirmed the trialed technique to be a good predictor of age for the entirety of the larger female sample (n = 533). Low inaccuracy (3.86 years) and Bias (0.69 years) further indicate that a continuum-based approach, without pre-set phases or ranges, such as was utilized by this research holds the potential to be at least as effective as the currently available methodologies but with the added advantage of allowing for increased variation at the individual level. Age estimation by linear regression, or by simple addition, yielded estimation envelopes (intervals) of 22–23 and 24 years, respectively, which remain narrow enough to be forensically useful while still wide enough to maximize accuracy in mature adults.