IEEE Spectrum covers a new research study looking at the accuracy of a method for determining the age-at-death of skeletal remains: “Errors Found in Forensic Software Meant to Assess Age-of-Death of Skeletal Remains”.
Research conducted by biological forensic scientists at North Carolina State University and the University of South Florida has uncovered “serious problems” in a recently released forensic software application available online called DXAGE that is supposed to predict the age-at-death of skeletal remains based on bone mineral density.
The study, published in the Journal of Forensic Sciences, reported that the software’s predicted ages could be off by 14.25 years on average when DXAGE-generated results were compared against known samples. The system’s accuracy was particularly poor for the remains of elderly individuals.
Since the software does nothing more than apply a set of algorithms to observations taken on bone, its results can be no better or worse than the variability of age-related changes in bone. That variability is really big! Biological anthropologists recognize that we cannot accurately estimate the age of older individuals, errors of 15-20 years on age estimates are very common.
So my reaction to this story is, “How did a method for age-at-death estimation that made claims of greater accuracy get started in the first place?”
It is just misleading to think that software gives better accuracy than an expert armed with the same statistics. It’s the white coat phenomenon. Unfortunately, the misperception of “computer precision” has huge influence on juries.
Bone mineral density changes are an interesting consequence of aging, and they have been the topic of some debate as applied to the ages of Neanderthals and other prehistoric people. When we look at ancient populations, there are the possibility of nutritional differences, lifestyle differences, and genetic differences that may have influenced both the peak bone density and the pattern of age-related bone loss.
All these are reasons why we cannot be very definitive about the age-at-death of most older adults in the fossil record. Once they have progressed to a point far enough beyond third molar eruption that tooth wear is not an accurate indicator of age, there are few biological indicators that would not also vary across populations for many reasons.