U.S. flag

An official website of the United States government, Department of Justice.

Quantifying Error Rates for the Measurement of Human Skeletal Remains

In response to the National Academy of Sciences’ call for scientific data to support forensic evidence, researchers revised forensic anthropology procedures to include an “error metric” for the measurement of human skeletal remains.
Date Published
July 10, 2017

When confronted with a human skeleton of an unidentified person, forensic anthropologists conduct well-established procedures to attain a set of measurements to determine the sex, ancestry, and stature of the person. Although there are many methods and techniques involved in making osteometric measurements, little work has been done to investigate the error rates associated with such measurements.

This NIJ-supported project, carried out by researchers with Lincoln Memorial University and the University of Tennessee, involved scores of skeletal measurements conducted by four experts to better quantify measurement error in a metric that could be included in the laboratory manual “Data Collection Procedures for Forensic Skeletal Material.”

“Measurement error can be minimized by using appropriate instrumentation, understanding the measurement definition, and by using highly reliable and repeatable measurements,” the researchers said in their study, titled, Evaluation of Osteometric Measurements in Forensic Anthropology. “Knowing the reliability of a given measurement provides a foundation from which to proceed with metric estimations of sex, ancestry, and stature . . .” the researchers further stated.

For the study, four “observers” of differing experience levels, measured elements of 50 skeletons, with 99 measurements taken on each skeleton. After all 50 skeletons had been measured once, the process was repeated three more times, for a total of four rounds of measurements.

The data were analyzed to assess measurement reliability and repeatability. The researchers then calculated the relative technical error of measurement (TEM) that represents the variability encountered between the observers when the same measurements were taken multiple times. The researchers next developed a scaled error index (SEI), another procedure to determine and compare variability of the measurements.

“On a broad scale,” the researchers said, “the results of this work provide foundational knowledge for forensic case analyses, research, data collection, and method development.” The researchers concluded that, “ultimately, the impact on the criminal justice system will be an improved and more accurate reference database and methods for identifying unknown decedents.”
The new data were included in the latest edition of Data Collection Procedures for Forensic Skeletal Material, which can be downloaded in PDF form from the University of Tennessee Forensic Anthropology Center website.

About This Article

The research described in this article was funded by NIJ cooperative agreement number 2013-DN-BX-K038, awarded to Lincoln Memorial University. This article is based on the grantee report “Evaluation of Osteometric Measurements in Forensic Anthropology,” (pdf, 13 pages) by Natalie Langley, Lincoln Memorial University; Lee Jantz, University of Tennessee.

Date Published: July 10, 2017