When DNA Won't Work

Within the criminal justice system, DNA (deoxyribonucleic acid) evidence has often been heralded as the gold standard of forensic science. In a 2009 U.S. Supreme Court decision, Chief Justice Roberts wrote that "DNA testing has an unparalleled ability both to exonerate the wrongly convicted and to identify the guilty. It has the potential to significantly improve both the criminal justice system and police investigative practices." The phrases “unparalleled ability” and “significantly improve” reflect the high standard that DNA has attained in both forensic science and the entire criminal justice system.

Forensic DNA technology has a major advantage over other forensic science fields because of its reliance on statistics and its historical development from medical science, which relies on double-blind testing, error analysis, and rigorous peer review. These factors distinguish DNA analysis from other forms of forensic analysis such as fingerprinting, ballistics, trace evidence, forensic anthropology (bones), handwriting analysis, and others. But every analytical field has its limits, and can be misappropriated. This article summarizes some of the key areas where the use of forensic DNA can be improved and includes proposed remedies.