Contrary to what many would like to believe, fingerprint evidence isn't all that reliable. Partial prints and smudged prints can be difficult to read, and in the U.S. at least, fingerprint analysis is left to individual interpretation rather than a set of standards outlining what can be considered a match.
That could soon change, though. A statistical tool developed by a Department of Defense analyst is able to take two fingerprints and tell how probable it is that they came from the same person, according to Gizmodo. The software program, called FRStat, was used in a courtroom for the first time in February and is now available to any lab that wants to test it out.
Henry Swofford, of the U.S. Army Criminal Investigation Laboratory at the Department of Defense, spent four years working with statisticians to develop the software. It works by comparing images of the small features of fingerprint minutiae (ridges) against "similarly marked, known matches" in a database. The software is then able to calculate the likelihood that the prints were left by the same individual. A paper outlining the statistical method was published in the journal Forensic Science International.
"I want to strengthen the foundations of our science," Swofford told Gizmodo. "I also want to make sure the evidence is presented in a way that the guilty people are convicted, and the innocent are exonerated."
A 2011 study found a false positive rate of 0.1 percent among fingerprint readings, and there have been numerous high-profile cases of wrongful convictions over the years. In one example, Brandon Mayfield, a lawyer from Oregon, was arrested in connection with the 2004 Madrid train bombing after four experts agreed that his prints matched ones found on a bag at the scene. He was eventually released after that proved to be a mistake.
While FRStat isn't the first technology that attempts to make fingerprint analysis more accurate, it's the first one that has been developed for widespread, practical usage, according to Gizmodo.