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All That Glitters Isn't Gold DNA forensics are not always as reliable as people think.

The increasing use of DNA evidence has revolutionized criminal investigations. Over the past several years, DNA forensics—once thought to be a less reliable identifier than other forensic techniques, such as latent fingerprinting—have now become the evidentiary gold standard in criminal prosecutions. At the same time, non-DNA-based forensic techniques that have incarcerated thousands are coming under fire. 

The policy implications of this shifting dynamic—what Michael Lynch and colleagues call an “inversion of credibility”—can be most clearly seen in the National Research Council’s 2009 report, Strengthening Forensic Science in the United States: A Path Forward. The committee found remarkable shortcomings in what they call the forensic science knowledge base, noting that the scientific theories and methods used to substantiate many forensic claims frequently cannot withstand close scrutiny. Although the committee acknowledges that DNA forensics are not always perfect, the report and its recommendations are framed by an implied yet powerful claim: non-DNA forensic techniques should live up to the gold standard created by DNA typing. But this framing has its own serious drawbacks that obscure much deeper issues concerning both technical matters related to the scientific validity of extending basic DNA identification techniques to novel applications and the ethical, legal, and social implications of DNA forensics’ expanding uses.

The increasing use of DNA evidence has revolutionized criminal investigations. Over the past several years, DNA forensics—once thought to be a less reliable identifier than other forensic techniques, such as latent fingerprinting—have now become the evidentiary gold standard in criminal prosecutions. At the same time, non-DNA-based forensic techniques that have incarcerated thousands are coming under fire. 

The policy implications of this shifting dynamic—what Michael Lynch and colleagues call an “inversion of credibility”—can be most clearly seen in the National Research Council’s 2009 report, Strengthening Forensic Science in the United States: A Path Forward. The committee found remarkable shortcomings in what they call the forensic science knowledge base, noting that the scientific theories and methods used to substantiate many forensic claims frequently cannot withstand close scrutiny. Although the committee acknowledges that DNA forensics are not always perfect, the report and its recommendations are framed by an implied yet powerful claim: non-DNA forensic techniques should live up to the gold standard created by DNA typing. But this framing has its own serious drawbacks that obscure much deeper issues concerning both technical matters related to the scientific validity of extending basic DNA identification techniques to novel applications and the ethical, legal, and social implications of DNA forensics’ expanding uses.

Osagie K. Obasogie and Troy Duster, "All That Glitters Isn't Gold," Hastings Center Report 41, no. 5 (2011): 15–17.