Science-Based Forensic Evidence: Getting the Science Right in Criminal Investigations

Science and the Law Valid and reliable forensic science is crucial for apprehending suspected criminals and helping to determine guilt or innocence at trial. However, there have long been assertions that many of the forensic sciences are neither valid nor reliable. In many cases, reports and testimony based on substandard science contributed to the convictions of individuals later proved innocent through DNA testing. The limitations of current forensic practices are of great concern to public policymakers. In 2009, the National Academy of Sciences issued a report critical of the scientific foundation of forensic sciences, excepting DNA testing. This critique prompted policymakers in both the U.S. Congress and the Executive Branch to explore remedies. For example, in 2013 the U.S. Department of Justice and the National Institute of Standards and Technology established a National Commission on Forensic Science, intended to improve the reliability of criminal investigations. This session addresses developments in two forensic fields that are often key factors in criminal investigations: latent fingerprint analysis and fire investigation. For years, some fire investigators have relied on mistaken theories about how to determine the origin and cause of a fire, leading to dozens of later exonerations. Fingerprint examination, like many other forensic fields, depends on human judgment and interpretation which can lead to cognitive bias in determining matches and possible errors. Panelists will discuss how the weaknesses of these practices are being addressed.