Forensic researchers have for the first time established science-based standards for identifying human remains based on X-rays of an individual’s spine, upper leg or the side of the skull.
“In the past, forensic experts have relied on a mixed bag of standards when comparing ante mortem and post mortem X-rays to establish a positive identification for a body – but previous research has shown that even experts can have trouble making accurate identifications,” says Ann Ross, lead author of a paper on the new standards and a professor of anthropology at North Carolina State University.
“We’ve created a set of standards that will allow for a consistent approach to identification – that can be replicated – and that allows experts to determine probabilities for an identification,” Ross says. “For example, you could say with 85 percent certainty that a body is a specific individual.”
The researchers compared ante mortem and post mortem lateral craniofacial (side of the skull) X-rays for 20 individuals, and did the same for X-rays of the vertebral column (spine) for 50 individuals, and X-rays of the proximal femur (upper leg) for 23 individuals. The researchers used these evaluations to develop location-specific standards for each skeletal region. The researchers focused on these skeletal regions because they are among the most frequently X-rayed in a clinical setting.
The researchers then used additional, unmatched X-rays to test the accuracy of the standards in two ways. First, they tested the standards to see how likely they were to accurately identify a body. Second, they ran separate analyses to see how likely the standards were to “misclassify” an identification – to provide a false-positive or false-negative result.