Fingerprint matching techniques seed reform.

• Position: Criminology - Critical essay

Fingerprint matches--key to fighting international terrorism and keeping criminals off the street--no longer are foolproof, warns Edward Imwinkelried, professor of law at the University of California, Davis. He contends that the reliability of fingerprint identification has declined while the population of the world--and its fingerprints--has exploded.

"We can no longer naively assume the reliability of our current fingerprint standards," he stresses. "Given the stakes--not only justice in a particular case, but national security itself--we must do better." Imwinkelried and his research co-author Mike Cherry, who is vice chair of the digital technology committee of the National Association of Criminal Defense Lawyers, urge reforms.

The current matching process identifies ridges within a fingerprint and categorizes it into one of three general patterns--including loops, arches, and whorls--and their subpatterns, and maps predetermined shapes and contours. A fingerprint is said to match when the pattern, subpattern, and some of the shapes and contours roughly correspond with each other.

In the late 1800s, Sir Francis Galton developed the first system for classifying and identifying fingerprints. He is quoted as having said that the odds of two individual fingerprints being the same are one in 64,000,000,000. The authors point out that the current world population exceeds 6,000,000,000 persons, and most have 10 prints. In short, they say, the world population of fingerprints now exceeds the odds Galton estimated.

At the same time, the authors...