for National Geographic News
On hit TV shows like CSI and Crossing Jordan, crime-solving forensic science may produce slam-dunk evidence and tidy endings.
In real life, forensic science is far less certain.
"The underlying principles of the identification forensic sciences have never been rigorously scientifically proven," said Jay Siegel, director of the undergraduate forensic science program at Indiana-Purdue University in Indianapolis.
"This includes handwriting, fingerprints, and firearms, and tool marks," he said.
According to a new study, traditional forensic analysis often relies on untested assumptions and semi-informed guesswork. It can also sometimes produce the wrong results.
Drawing on data from 86 DNA exoneration cases, the researchers found that forensic science testing errors and false or misleading testimony by forensic scientists had been leading causes in the false convictions.
One of the researchers, Jonathan Koehler, says it's time for forensic sciences to adopt the culture of other sciences.
"This includes being more conservative, requiring empirical support for claims, adopting higher professional standards, and generally conceding the important role that the possibility of error plays in interpreting results," said Koehler, a professor of behavioral decision-making at the University of Texas in Austin.
The study appears in the current issue of the journal Science.
Little research has been conducted on the accuracy of traditional forensic sciences, such as the analysis of handwriting, firearm marks, fingerprints, hairs, and fibers.
"My guess is that the broader scientific community just assumed that the claims and assumptions of the traditional forensic sciences were rigorously tested at an earlier time," Koehler said.
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