Forensic science, often used to produce evidence for criminal trials using such techniques as fingerprint analysis, is “badly fragmented” and unreliable in the U.S., according to a report by the National Academy of Sciences. Crime laboratories around the country are grossly underfunded, lack a scientific foundation and are compromised by critical delays in analyzing physical evidence…. The report calls into question the scientific merit of virtually every commonly used forensic method, including analysis of fingerprints, hair, fibers, blood spatters, [and] ballistics [The New York Times].
According to the report “no forensic method”—with the notable exception of DNA analysis—”has been rigorously shown able to consistently, and with a high degree of certainty, demonstrate a connection between evidence and a specific individual or source.” Of particular concern is the use of comparative forensic methods like hair or fingerprint analysis to match a piece of evidence to a particular person, weapon, or place [New Scientist].
DNA was excluded from the criticism because “the chances of a false positive are minuscule, but also because the likelihood of such errors is quantifiable. Studies have been conducted on the amount of genetic variation among individuals, so an examiner can state in numerical terms the chances that a declared match is wrong.” Other forensic techniques, however, have not been studied to determine how many sources might share similar features, or to quantify the level of uncertainty in any measurement made.
