Keith Allen Harward served 33 years in jail after being convicted of rape and murder, largely on the strength of bite mark evidence. He was subsequently found to be innocent on the basis of DNA evidence and released. During his incarceration the actual criminal remained free and committed other crimes. This miscarriage of justice was the result of bad science. Bite mark evidence has been shown to lack any scientific credibility, yet it continues to be used in court. To a public accustomed to watching crimes being solved on television shows, where the results are always pristine and the guilty are always convicted, there is a perception that forensic science is flawless. The reality is that it is not, and we are in danger of halting and even reversing the considerable progress that has been made in improving it.

In 2009, the National Academy of Sciences evaluated the state of forensic science and, shockingly, concluded that many of the techniques used in court actually have no scientific validity. This means that the science used to convict the accused is neither reliable, nor robust and cannot be trusted in a court of law. In response to this report, the government established the National Commission of Forensic Science (NCFS) in 2013, which was tasked to explore these issues and make recommendations for improvement (all of the authors of this piece have served on the NCFS). Administered jointly by the Department of Justice and the National Institute of Standards and Technology, the commission has worked diligently over the past four years to identify problems and propose changes to strengthen forensic science.

This progress is now in danger of being undone. On April 10, the Justice Department, under the leadership of Attorney General Sessions, refused to extend the term of the NCFS. The demise of the NCFS is a tremendous missed opportunity for the progress of forensic science and criminal justice. The NCFS brought together diverse stakeholders including forensic scientists, judges, lawyers, victims’ advocates, law enforcement, and practicing independent scientists. NCFS was the only formal link between mainstream science and the communities that support and consume the products of forensic science, most notably the criminal justice system. During the four years in which it operated, the NCFS made considerable progress in bridging the scientific and legal disciplines. For example, the NCFS found such language as “reasonable scientific certainty: to be meaningless and recommended that it not be used in court, since it gave the false impression of scientific validity.

Even more importantly, the NCFS recommended that all forensic techniques should be independently validated before being used in criminal investigations. Some have been; but too many others have not. Bite mark evidence is one example; despite lacking any scientific foundation, it is, incredibly, still being admitted into the courts. Last year the President’s Council of Advisors on Science and Technology identified firearms identification and footwear analysis as also lacking scientific validity.

Medical therapies, airplanes and electrical devices are tested by independent entities before they can be used routinely; the public demands it and takes for granted that this has occurred. The public has the right to expect the same of forensic techniques, given the substantial consequences of the ‘evidence’ produced in court. Independent and unbiased assessment is fundamentally essential to determining the efficacy of any technique claiming to be scientific. By stating this principle clearly, the NCFS established an important precedent that should have far reaching consequences on the future development of forensic science. Now the public should demand this validation.

Forensic techniques such as fingerprints and firearms analysis were developed by law enforcement to help solve crimes. Unlike DNA analysis, these practices were not borne of science, and evolved in a legal system that is binary, adversarial and absolute, requiring verdicts of guilty or not guilty. In contrast, mainstream science functions with an acceptance that all knowledge is provisional and certainty is described by probability. These two approaches create tremendous tension between the ways scientists and legal practitioners perceive evidence.

To scientists, all evidence, be it news of a new particle in physics or evidence used in court must come with a definable and measurable certainty. Any statement such as “it’s a match” must be delivered with cautionary information about the error in the measurement. Every measurement made by human beings is subject to some statistical amount of error and uncertainty. It may be large or vanishingly small, but it does exist. We need to know the uncertainty involved when fingerprints, ballistics, material analysis and other evidence is used in court. The truth, the whole truth, and nothing but the truth.

The Justice Department now proposes to improve forensic science by moving its oversight and development to an office within the department. This is precisely the opposite of what was recommended by the National Academy of Sciences report and the NCFS. It is a step backwards, because it reinforces the conditions that contributed to the current problems, namely, placing this discipline within the control of law enforcement and prosecutors. The Justice Department is home to many dedicated public servants including scientists whose passion for justice is unquestioned. However, DOJ is not a scientific body, and it is difficult to see how forensic science can become a true science in that environment. Science flourishes when free and independent; only then can the tools and technology that it creates be truly reliable.

Scientists and the justice department can do the necessary research to put forensic techniques on a scientifically sound footing, or they can retreat into the status quo in which untested forensic practices are admitted in court simply because they have been in the past. Proclaiming evidence to be scientific does not make it so. Given this state of affairs, we are bewildered by the decision to end the NCFS. Questions about the validity of forensic science will not go away. Failure to address them will lead to further convictions of innocent people. For our society, the stakes don’t get much higher.