By Sheeva Azma
Judges have significant flexibility and resources in interpreting scientific evidence brought to them, but they are not scientists.
To become a judge in the United States, one needs to typically first become a lawyer, and that training can be devoid of science courses. It may be surprising to know that, despite that, judges become gatekeepers of scientific evidence — they decide what stays and what goes in a court case. This mechanism for evaluating scientific evidence was established in a famous 1993 Supreme Court case called Daubert v. Dow Pharmaceuticals, Inc. which created what is known as “The Daubert Test.” The Daubert Test was a response to junk science being introduced in the courts, which led to injustice, products being removed from the market, and more.
As I’ve previously written, Daubert is not without its limitations. For example, in 2010, a man’s wrongful conviction was vacated due to faulty scientific evidence on habeus corpus — meaning that the defendant was unlawfully imprisoned due to the sham science. What ultimately brought justice to the case was a thorough examination of arson science, which was something missing from the first trial.
Judges have significant flexibility and resources in interpreting scientific evidence brought to them, but they are not scientists. They may devalue scientific evidence and even expertise in favor of other aspects of an argument that are more compelling and weighty to them. What’s more, structural issues within the legal system can make figuring out what is sound science and what is junk science a difficult task. It can be expensive and time-consuming for lawyers representing a defendant to bring in an expert to explain the science and why it is actually “junk” science.
Some types of forensic evidence, such as bullet holes, fingerprinting, and bite marks have been accepted in courts for decades, and judges are less likely to exclude evidence that previous judges have allowed in court. The adversarial nature of legal proceedings, pitting one side against the other, can often bring two scientific experts together, one on each side of the case, who don’t see eye to eye. What’s more, court cases are not typically decided by the science facts, but how well the case is argued.
One resource available to judges is The Reference Manual on Scientific Evidence. In its own words, it is “the leading reference source for federal judges for difficult issues involving scientific testimony.”
The Reference Manual writes in its Preface that judges face the challenging task of adjudicating “between parties’ differing interpretations of scientific evidence.”
“Science, meanwhile, advances,” it states. “Methods change, new fields are born, new tests are introduced, the lexicon expands, and fresh approaches to the interpretation of causal relations evolve. Familiar terms such as enzymes and molecules are replaced by microarray expression and nanotubes; single-author research studies have now become multi-institutional, multi-author, international collaborative efforts.”
The chapters of the Reference Manual deal with how science and the scientific method works, as well as individual subjects in science and engineering, including forensic evidence, DNA, statistics, neuroscience, toxicology, epidemiology, medical testimony, and mental health evidence.
The Reference Manual is published by the Federal Judicial Center (FJC), which is the research and education agency for the US judicial branch. The FJC provides educational programs and resources for judges and court staff. You can learn more about the Federal Judicial Center at www.fjc.gov.
Learn more about how science is used in the government
Fancy Comma is a science communications and policy consulting company with a mission to help scientists better understand science’s role in the US legislative, executive, and judicial systems. Check out our explainer blog on how science is used in the three branches of government. For more on science policy, visit our free resources or subscribe to our blog, newsletter, and/or YouTube channel.
Fancy Comma, LLC 