All That Glitters Isn’t Gold

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”[1]—can be most clearly seen in the National Research Council’s 2009 report, Strengthening Forensic Science in the United States: A Path Forward. Conducted at Congress’s request by a highly esteemed committee, this report—over three hundred pages—assesses the current state of forensic science.

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. They found an alarmingly “wide variability in capacity, oversight, staffing,
certification, and accreditation.”[2] For example, lack of transparency, susceptibility to bias, and questionable methodologies for friction ridge analyses (analyses of the prints left by...