Page 184 - Privacy in a Cyber Age Policy and Practice

172 PRIVACY IN A CYBER AGE

are vastly more reliable than other forensic scientific methods and police
tools, in particular the use of eyewitnesses and police line ups. According
to the National Research Council of the National Academies, “Except for
DNA, no method has been shown to be able to consistently and accu-
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rately link a piece of evidence to an individual or single source.” A 2009
report by the National Academy of Sciences that compared the reliability
of various forensic science methods found that DNA analysis was one of
the only methods grounded in real scientific theory and analysis, and
the only method for which estimating error probability was possible.
By contrast, the report found serious flaws with, and a lack of scientific
basis for, analyzing and matching fingerprints, tire tracks, footprints,
firearms, hairs, written or printed documents, burn and accelerant pat-
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terns, bite marks, and some blood patterns. The consequences of flawed
analysis can be dire, as when Cameron Todd Willingham, a Texas man,
was convicted of murdering his three children by arson (based on faulty
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burn analysis from arson “experts”) and executed. Of the 225 wrong-
ful convictions overturned by DNA testing through 2009 (more on this
later), more than half “involved unvalidated or improper forensic sci-
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ence.” Although conclusive error rates for forensic science methods are
inherently elusive, that DNA analysis is one of the few forensic science
methods based on sound science rather than the lay “wisdom” of law
enforcement officials suggests it may produce fewer errors than other
methods. In particular, the reliability of DNA evidence strongly contrasts
with that of eyewitness testimony, which has long been criticized for
its reliance on faulty human memory. 100 Eyewitness accounts yield false
positives about a third of the time, 101 and 72 percent of convictions over-
turned through DNA testing were based at least in part on eyewitness
testimony. 102
Evidence shows that increased forensic DNA usages are a very effec-
tive tool for enhancing public safety. 103 Several studies have examined
the relationship between the application of forensic DNA usages and crime
clearance rates. One study—a particularly persuasive, randomized controlled
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trial—found that when DNA testing was used the percent of burglaries
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cleared increased by as much as 40 percent compared to control groups.
Another study found that DNA database expansion generated great ben-
efits for crime clearance in the categories of sexual assault and robbery with
or without a firearm. 106 A systematic review of studies on the effectiveness
of DNA evidence in investigating crime “compared to other more tradi-
tional forms of investigation” found “generally positive results regarding
the utility of DNA testing [. . .] when used to investigate a broad range of
crime types.” For these reasons, the review concluded that DNA evidence’s
utility for crime investigations is sound. 107