Researchers Discover Wire-Cutting Evidence Is Too Unreliable for Court
by Douglas Ankney
According to an article appearing on June 10, 2024, in the Proceedings of the National Academy of Sciences, researchers have concluded that wire-cutting evidence should not be admissible in court unless additional information about the number of comparisons made is provided. A study entitled “Hidden Multiple Comparisons Increase Forensic Error Rates” authored by Susan Vanderplas, Assistant Professor of Statistics at the University of Nebraska—Lincoln, along with Heike Hoffman and Alicia Carriquiri from Iowa State University’s Department of Statistics explained that with wire-cut evidence, forensic examiners try to match tiny striations on the cut ends of wires recovered from crime scenes to tools in belonging to a suspect. When done using an automated process, a comparison microscope coupled with pattern-matching algorithms finds possible matches pixel by pixel. This process may lead to thousands upon thousands of comparisons, and because these comparisons are made internally, the shocking number is hidden from the examiners.
In a somewhat unexpected twist, the researchers discovered that too many comparisons may lead to false matches—with the rate of false identifications being one in ten or higher. VanderPlas said, “It is somewhat of a counter intuition. You are more likely to find the right match, but you’re also more likely to find the wrong match.”
The researchers concluded that wire-cut evidence should not be admitted in court unless:
“Examiners report the overall length or area of materials used in the examination process, including blade length and wire diameter.”
“Studies be conducted to assess both false discovery and false elimination error rates when examiners are making difficult comparisons. Studies should link the length and area of comparison to error rates.”
“The number of items searched, comparisons made and results returned should be reported when a database is used at any stage of the forensic evidence evaluation process.”
Source: phys.org
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