Forensic science plays a crucial role in our criminal justice system. If the right evidence is present, forensic science can help investigators solve crimes, including cases that have long been cold. It can help exclude innocent people from an investigation or exonerate them in cases of wrongful conviction. And it can help juries as they make decisions that have enormous consequences on people’s lives.
But how do we know if we can trust the results of forensic analysis when making important decisions? In other words, how do we know if forensic methods are reliable?
NIST has begun a series of studies that will help answer this question based on a review of the scientific evidence. These studies, called “scientific foundation reviews,” focus on the published scientific literature and other relevant sources of data that can shed light on questions of reliability. These reviews will:
NIST's approach to conducting these reviews is described in NISTIR 8225: NIST Scientific Foundation Reviews.
To date, NIST has begun scientific foundation reviews in the following areas:
The field of digital forensics is constantly changing as new devices and applications become available. This review documents and evaluates the scientific foundations of digital evidence examination and recommends steps to advance the field. More information about the NIST Interagency Report 8354 Digital Investigation Techniques: A NIST Scientific Foundation Review is available here.
DNA evidence that contains very small quantities of DNA or a mixture of DNA from several people can be difficult to interpret reliably. This review focuses on the methods that forensic labs use when interpreting these challenging types of DNA evidence. More information about the NIST Interagency Report 8351-DRAFT “DNA Mixture Interpretation: A NIST Scientific Foundation Review” is available through the press release and the report's home page.
Bitemark analysis is a forensic technique in which marks on the skin of a biting victim are compared with the teeth of a suspected biter. In addition to a review of the scientific literature, this review includes a report from an October 2019 workshop, hosted by the Center for Statistics and Applications in Forensic Science (CSAFE), where odontologists, researchers, statisticians, lawyers and other experts addressed scientific questions around bitemark analysis. More information about the NIST Interagency Report 8532 Bitemark Analysis: A NIST Scientific Foundation Review is available here.
Forensic ballistics experts can assess whether a specific gun was used in a crime by examining bullets and cartridge cases under a comparison microscope. This study will document the scientific foundations of that method and assess its reliability by evaluating the scientific literature on error rates.
Performing forensic footwear examinations involves photographing and collecting footwear impressions from a crime scene, analyzing the evidence in the lab and comparing the marks to known footwear impressions on the same or similar substrate. The NIST scientific review on footwear impressions will aim to identify what established scientific laws and principles underpin the forensic science methods and what publicly available empirical data exist to support the methods practitioners use to analyze the evidence.
These scientific foundation reviews will be useful in a number of ways. First, they can help establish trust in methods that, when properly applied, rest on solid scientific foundations. Second, they can help forensic practitioners, investigators, courts and other stakeholders understand the capabilities and limitations of forensic methods and help ensure that those methods are used appropriately. Third, by identifying knowledge gaps, they can help provide strategic direction for future research.
These studies will also fulfill a critical need identified in a landmark 2009 report by the National Academy of Sciences. Titled Strengthening Forensic Science in the United States: A Path Forward, that report called for “studies establishing the scientific bases demonstrating the validity of forensic methods.” In addition, in 2016, the National Commission on Forensic Science recommended that NIST “conduct independent scientific evaluations of the technical merit of test methods and practices used in forensic science disciplines.” The U.S. Congress appropriated funds for NIST to conduct these reviews starting in 2018.
Each scientific foundation review will result in a report that will be freely available on this website. If you’d like to receive an alert when the reports are published or when related information becomes available, please sign up for our email list.