NIST Seeks Public Comments on Draft Report of Forensic Bitemark Analysis

Illustration of a typical human dentition viewed in standard anatomical position. Credit: K. Sauerwein/NIST

The National Institute of Standards and Technology (NIST) has published Bitemark Analysis: A NIST Scientific Review. The draft report will be open for public comments through Dec. 12, 2022.

The report details the findings from a NIST review of the scientific foundations of bitemark analysis, a forensic technique used to compare the marks on the skin of a biting victim with the teeth of a potential biter.

There were several key takeaways identified as part of the scientific review, including one that states that bitemark analysis is not supported by sufficient data:

Forensic bitemark analysis lacks a sufficient scientific foundation because the three key premises of the field are not supported by the data. First, human anterior dental patterns have not been shown to be unique at the individual level. Second, those patterns are not accurately transferred to human skin consistently. Third, it has not been shown that defining characteristics of those patterns can be accurately analyzed to exclude or not exclude individuals as the source of a bitemark.

The Center for Statistics and Applications in Forensic Evidence (CSAFE) hosted a NIST-funded meeting in 2019 where forensic dentists, researchers, statisticians, lawyers and other experts addressed scientific questions around bitemark analysis. A meeting summary was written by Alicia Carriquiry, CSAFE director, and Hal Stern, CSAFE co-director. The CSAFE Bitemark Thinkshop Report provided information for the NIST review and has been published as a supplement.

NIST hosted a three-hour webinar on Oct. 27 to discuss the draft report and its findings. A recording of the webinar will be posted soon on the NIST website. For more information, visit

Read the NIST news release on the report at

NIST Webinar will Discuss the Scientific Foundation Review on Bitemark Analysis

The entrance sign at NIST's Gaithersburg campus. Credit: J. Stoughton/NIST

The National Institute of Standards and Technology (NIST) will host a webinar to discuss its latest Scientific Foundation Review on bitemark analysis. The webinar will be held Oct. 27 from 1–3 p.m. EDT.

NIST Scientific Foundation Reviews document and evaluate the scientific basis for forensic science methods and practices. These reviews focus on the published scientific literature and other relevant sources of data that can provide information on questions of reliability. To date, NIST has begun foundation reviews on DNA mixture interpretation, digital evidence, bitemark analysis, and firearms examination.

The upcoming webinar will review the contents and findings in a draft report, Bitemark Analysis: A NIST Scientific Foundation Review,  and provide an opportunity for attendees to ask questions. The draft report will be open for public comment through Dec. 12, 2022. The authors will consider all comments submitted before publishing a final version of the report. For more information

The Center for Statistics and Applications in Forensic Evidence (CSAFE) hosted a workshop in 2019 where forensic dentists, researchers, statisticians, lawyers and other experts addressed scientific questions around bitemark analysis. A summary of the workshop was written by Alicia Carriquiry, CSAFE director, and Hal Stern, CSAFE co-director. It provided information for the NIST review and has been published as a supplement to it.

To register for the webinar, visit

For more information about NIST scientific foundation reviews, go to

Registration is Open for Forensics@NIST 2022

The entrance sign at NIST's Gaithersburg campus. Credit: J. Stoughton/NIST

The National Institute of Standards and Technology (NIST) has announced the dates for its annual Forensics@NIST. The virtual event will be held Nov. 8–10, 2022.

Forensics@NIST will feature presentations from NIST scientists on how they are using advanced methods in metrology, computer science and statistics to strengthen forensic science. The topics to be covered are:

  • drugs/toxins
  • statistical methods in forensic science
  • firearms and toolmarks
  • forensic genetics
  • trace
  • digital and multimedia
  • biometrics

As a NIST Center of Excellence, the Center for Statistics and Applications in Forensic Evidence (CSAFE) will present on Nov. 10 from 3–4:30 p.m. EST. CSAFE researchers will provide an overview of the CSAFE resources available to the forensic science community and give updates on firearms and toolmarks, bloodstain pattern and handwriting analysis projects.

  • CSAFE Overview

    Presenter: Alicia Carriquiry, CSAFE director and Distinguished Professor and President’s Chair in Statistics at Iowa State University
  • CSAFE Firearms and Toolmarks Analysis

    Presenter: Maria Cuellar, assistant professor of criminology at the University of Pennsylvania
  • CSAFE Bloodstain Pattern Analysis

    Presenter: Tong Zou, graduate student in statistics at the University of California, Irvine
  • CSAFE Handwriting Analysis

    Presenter: Danica Ommen, assistant professor of statistics at Iowa State University

    Presenters: Carriquiry, Cuellar, Zou and Ommen

NIST will also hold optional workshops on Nov. 14–15, 2022. Each workshop is limited to 175 attendees, and registrations will be approved on a first-come, first-serve basis. Attendees must attend the main sessions on Nov. 9–10 to register for a workshop. The list of workshops is below:

  • How It’s Made: NIST Forensic DNA Reference Materials
  • NIST 2022 Forensic Cannabis Workshop
  • Mass Spectral Interpretation – Tips and Tools for GC-EI-MS and High-Resolution MS Data
  • Process Mapping
  • Application & Implementation of 3D Technology, Algorithms, and Statistics for Forensic Firearm and Toolmark Analysis

For more information or to register, visit

OSAC Public Update Meeting Set for Sept. 13

Organization of Scientific Area Committees (OSAC) for Forensic Science

The Organization of Scientific Area Committees (OSAC) for Forensic Science will host its annual Public Update Meeting on Sept. 13, 2022, from 1–4:30 p.m. EDT. Attendees will learn how OSAC is making an impact on the forensic science community through standards.

The virtual meeting will feature presentations from the seven chairs of OSAC’s Scientific Area Committees and the chair of the Forensic Science Standards Board. Each presenter will describe their committee’s activities, including the latest standards actions, research gaps, challenges being addressed and priorities for the coming year.

There is no fee to attend, but registration is required. The meeting agenda and registration information are available at

The OSAC works to strengthen the nation’s use of forensic science by facilitating the development of scientifically sound forensic science standards and by promoting the use of those standards by the forensic science community. OSAC has over 500 members and 275 affiliates that work together to draft and evaluate forensic science standards through a transparent, consensus-based process that allows for participation and comment by all stakeholders. For more information about OSAC and its programs, visit

Two New Forensic Firearm Examination Standards Added to the OSAC Registry of Approved Standards

Organization of Scientific Area Committees (OSAC) for Forensic Science

The Organization of Scientific Area Committees (OSAC) for Forensic Science has placed two new standards covering firearm and toolmark analysis on its Registry of Approved Standards. According to a recent news release, these new standards provide guidance on implementing 3D technologies in forensic labs.

The new standards are:

The new release noted that researchers have been developing new methods that use 3D surface scanning microscopes to produce 3D models of the bullets, and computer algorithms can then compare the microscopic features of the two virtual bullets to measure how similar they are.

“These standards give labs guidance on purchasing and setting up a 3D system, validating it to ensure that it produces accurate results, and implementing it into their workflow,” said Erica Lawton, a firearms examiner at the Alabama Department of Forensic Sciences who, as the chair of OSAC’s Firearms and Toolmarks Subcommittee, helped guide the new standards through the approval process.

According to the news release, a benefit of using a 3D system for comparing the surface features of two bullets or cartridge cases is that the algorithm generates a numerical score that describes how closely the two surfaces match. “That match statistic expresses the amount of uncertainty in the analysis, and police investigators, jurors and others can use it when weighing the evidence. With the traditional method, an expert can only give a subjective opinion as to whether two bullets or cartridge cases were fired from the same gun. They cannot provide a match statistic,” stated the news release.

The National Institute of Standards and Technology (NIST) administers OSAC as part of its larger Forensic Science Program, which works to strengthen forensic science through advanced research and improved standards. NIST also supports laboratory efforts to implement standards on the OSAC registry via a cooperative agreement with the American Academy of Forensic Sciences. For more information on OSAC’s role in the standards development process, visit the OSAC website.

The Center for Statistics and Applications in Forensic Evidence (CSAFE), a NIST Center of Excellence, is developing statistical and scientific foundations for assessing and matching firearms and toolmarks. Learn more about CSAFE’s work in this area at

NIST Updates Software Reference Library

Software files can be identified by a sort of electronic fingerprint called a hash. The NSRL dataset update makes it easy to separate hashes indicating run-of-the-mill files from those that might contain incriminating evidence, making investigative work easier. Credit: N. Hanacek/NIST

The National Institute of Standards and Technology (NIST) announced an update to the National Software Reference Library. The expanded, more searchable database will make it easier to sift through seized computers, phones and other electronic equipment.

The database plays a frequent role in criminal investigations involving electronic files, which can be evidence of wrongdoing. According to the NIST news release, “In the first major update to the NSRL in two decades, NIST has increased the number and type of records in the database to reflect the widening variety of software files that law enforcement might encounter on a device. The agency has also changed the format of the records to make the NSRL more searchable.”

NIST said that criminal and civil investigations frequently involve digital evidence in the form of software and files from seized computers and phones. Investigators need a way to filter out the large quantities of data irrelevant to the investigation so they can focus on finding relevant evidence.

The news release stated, “The update comes at a time when investigators must contend with a rapidly expanding universe of software, most of which produces numerous files that are stored in memory. Each of these files can be identified by a sort of electronic fingerprint called a hash, which is the key to the sifting process. The sophistication of the sifting process can vary depending on the type of investigation being performed.”

NIST reported that the NSRL’s reference dataset doubled from half a billion hash records in August 2019 to more than a billion in March 2022.

The new release notes why the dataset is important to digital forensic labs: “This growth makes the NSRL a vitally important tool for digital forensics labs, which specialize in this sort of file review. Such work has become a crucial part of investigations: There are about 11,000 digital forensics labs in the United States (compared with about 400 crime labs).”

The previous database version dates back 20 years, and while searching was possible, it was cumbersome. The new NSRL update will make it easier for users to create custom filters to sort through files and find what they need for a particular investigation.

The dataset and more information on the update are available at

The Center for Statistics and Applications in Forensic Evidence (CSAFE), a NIST Center of Excellence, conducts research addressing the need for forensic tools and methods for digital evidence. Learn more about this research at

NIJ Announces New Forensic Science Strategic Research Plan for 2022–2026

NIJ Forensic Science Strategic Research Plan 2022-2026

The National Institute of Justice (NIJ) Office of Investigative and Forensic Sciences has published its latest four-year Forensic Science Strategic Research Plan.

The plan focuses on improving the quality and practice of forensic science through innovative solutions that support research and development, testing and evaluation, technology, and information exchange.

As stated in the plan, “NIJ developed this Forensic Science Strategic Research Plan to communicate its research agenda and advance its forensic science research mission. The strategic priorities and objectives outlined in this plan closely parallel the opportunities and challenges faced by the forensic science community.”

NIJ identified five strategic research priorities:

Each priority includes a comprehensive set of objectives and action items.

According to the NIJ, the strategic research plan should interest many stakeholders, including crime laboratory professionals, researchers and technology developers, the legal community, and policymakers.

The Forensic Science Strategic Research plan is available to download at

New Study Explores Public Beliefs About the Reliability of Forensic Science

A forensic scientist looking at prints on a computer screen.

By Samantha Springer, a research assistant at the Center for Statistics and Applications in Forensic Evidence


As with many scientific fields, forensic science has faced public and expert criticism since its conception. In response, the discipline must find ways to increase confidence in its methods and usage. One potential means of doing so was examined in a recent paper by Carlos Miguel Ibaviosa and Jason M. Chin, who posited that increased transparency and openness could solve forensic science’s public image problem.

The paper “Beyond CSI: Calibrating public beliefs about the reliability of forensic science through openness and transparency” looks at the criticisms surrounding forensic science in three stages. To begin, the authors look closely at studies that have examined the CSI Effect, which hypothesizes that procedural shows like CSI, which show forensic science to be infallible, give the public an unrealistic view of the field, which could then impact how forensic evidence is weighed in court. Most hypotheses assume this effect causes the public to view forensic science in an overly-positive and trusting way. However, after reviewing studies with these hypotheses, the paper finds that findings are inconsistent and methods are poorly constructed.

After determining that the general public is not strongly swayed by versions of forensic science they see depicted on TV, the authors review studies performed over the past 11 years that have found the public’s view of forensic science to be one of skepticism.

Although the five studies reviewed were not all performed by the same researchers, their methods were relatively comparable, and all looked at participants’ ratings of reliability for multiple different forensic tests, including DNA and bitemark evidence.

Overall, data suggested a disconnect between what experts and research regard as accurate and what the public understands as being accurate.

An example of this can be found in DNA analysis. While viewed as the gold standard within the forensic science community, two studies conducted 11 years apart showed a decrease in public trust for DNA—from a 94% reliability rating in a 2008 study to 83% in 2019.

Also miscalibrated from actual scientific findings were public views of unvalidated methods such as bitemark analysis. One study conducted in 2015 found that the public rating of the reliability for bitemark analysis was 89.26%, higher than the rating for the much more reliable fingerprint analysis, which was deemed 88.15% reliable.

The differences in language, sample size, and other sample characteristics across the studies prevent a definitive conclusion about public views of forensic science over time and their relation to expert findings on reliability. However, the authors suggest the findings still indicate a cause for concern for forensic evidence practitioners and others in the forensic science field.

Following the reviews of these studies and the lack of impression the CSI effect has on the public, the question for the authors of the paper became what, then, was responsible for the disconnect regarding reliability of forensic evidence between experts and the public?

The suggested answer is that the ability of DNA methodologies to detect previous errors, that in many cases led to wrongful convictions, was widely reported on by news coverage, as were the reports by academic bodies criticizing some of the methods responsible for such miscarriages of justice. This could have contributed to an overall public distrust in forensic science that must now be mitigated, and thus the paper turns to possible ways in which the field can bolster its credibility.

The paper’s recommendations for improved public perception and credibility focus on three components supported by research:

  1. Epistemic trust. Epistemic trust is the trust in knowledge given to us by others. This trust, on the part of the public, consists of the perceived competence of the researcher, the benevolence they show regarding improving society, and the integrity with which they follow scientific principles. Acknowledging mistakes and uncertainty in their work secures public epistemic trust in a researcher.
  2. The promotion of openness and transparency in the scientific field. When this is done, high-quality science will be distinguishable from low-quality science, as the public and scientists involved will be able to review the data and methods of different studies. Even an expressed intention of transparency has been shown to strengthen the epistemic trust of the field.
  3. Alignment with public expectations. Studies found that participants view questionable research practices, such as selective reporting, as highly morally unacceptable, despite their use not being outwardly illegal. Following these preferences will show a willingness to engage with the public as well as a dedication to good methodology.

Read the Study

Beyond CSI: Calibrating public beliefs about the reliability of forensic science through openness and transparency, Science & Justice, published online Feb. 17, 2022.

OSAC Footwear & Tire Subcommittee Develops Process Map

An overview of the Footwear and Tire Examination Process Map developed by the OSAC Footwear & Tire Subcommittee

By Samantha Springer, a research assistant at the Center for Statistics and Applications in Forensic Evidence (CSAFE)


On June 8, 2022, the Organization of Scientific Area Committees for Forensic Science’s (OSAC) Footwear & Tire Subcommittee published a current practice document for footwear and tire examination.

The 37-page document consists of multiple process maps that cover a range of practices in the field of footwear and tire examination, including casts, gel lifts, known and unknown assessments, and different types of substrates with or without the presence of blood. Additionally, the flowcharts cover administrative processes such as verification and reporting, technical assessments, and administrative assessments.

The current practice document defines its purpose as five-fold:

  • help improve efficiencies while reducing errors,
  • highlight gaps where further research or standardization would be beneficial,
  • assist with training new examiners,
  • develop specific laboratory policies, and
  • identify best practices.

The document represents current practices instead of best practices and therefore does not necessarily endorse all the methodologies shown in the multiple process maps to ensure practitioners can find the process their lab uses. According to an article published by the National Institute of Standards and Technology (NIST), David Kanaris, Chair of the OSAC subcommittee, plans to release a more interactive version of the document in the future.

NIST facilitated the development of this process map through a collaboration between the NIST Forensic Science Program and OSAC’s Footwear & Tire Subcommittee.

Other OSAC subcommittees have released their process maps for other forensic science areas, including speaker recognition, DNA, friction ridge examinations, and firearms examinations.

CSAFE researchers Alicia Carriquiry, CSAFE director, and Jacqueline Speir, an associate professor at West Virginia University, are members of the OSAC Footwear & Tire Subcommittee.

Learn more about CSAFE’s work on footwear impression analysis at

Podcast Episode Discusses Weakness in Eyewitness Identifications and Their Use in the Courtroom

Empty Courtroom

By Samantha Springer, a research assistant at the Center for Statistics and Applications in Forensic Evidence (CSAFE)


Eyewitness identification was discussed in episode seven of The Ongoing Transformation, a podcast sponsored by Arizona State University and the National Academies of Sciences, Engineering, and Medicine (NAS). Jed Rakoff, senior United States district judge for the Southern District of New York and who worked with the National Academics to publish the 2014 report on eyewitness identification, spoke about his book, “Why the Innocent Plead Guilty and the Guilty Go Free: And Other Paradoxes of Our Broken Legal System.”

Although eyewitness identification is a form of evidence very compelling to jurors, Rakoff suggested there are many reasons such evidence should be met with more skepticism. In the 375 exonerations the Innocence Project has been involved with since 1989, it was found that nearly 70% of them involved eyewitness misidentification.

Some of the reasons for these misidentifications are simple situational causes, such as lighting, an obscured view, and a tendency to focus on a weapon rather than on the details of the person handling it.

Other reasons to be cautious of eyewitness testimony are more psychological. One concern Rakoff mentions is the racial effect, in which members of the same race are more capable of distinguishing minute facial details compared to a person of a different race. Another factor at play is memory. In an example given by Rakoff, when an eyewitness begins going through a photo lineup, they may have an image of the person they saw for a few moments in rough detail in their minds. After picking a photo, the details from their sighting and the details in the photo begin to merge until the eyewitness testifying at trial months later is certain of their wrongful identification.

A solution for decreasing this high number of eyewitness misidentifications suggested by Rakoff is to educate prosecutors on the fallibility of memory and vision and identify when those flaws affect an identification. A way he suggests this could be done is to replicate a program required of all federal judges in the United States he dubbed “baby judge school,” but whose technical name is the “Phase 1 Orientation Seminar for Newly Appointed District Judges.” This program educates judges on many concepts of the legal system, from ethical concerns they’ll need to be aware of, how to organize caseloads, and how to make evidentiary decisions. Rakoff believes a similar program could teach prosecutors more about eyewitness identifications and their limitations.

Rakoff is also in favor of adopting a U.K. practice in which criminal prosecutors spend six months working as a criminal defense attorney every three years. He believes that, among other things, this can provide prosecutors with important insights on how to handle forensic evidence in cases.

Regarding forensic science reform in general, Rakoff believes the National Commission on Forensic Science, created under President Obama and whose term lapsed under President Trump, should be renewed. In its four years, the commission made 59 recommendations to the Department of Justice that could also be applied to state police and prosecutors.

Additionally, Rakoff believes that The National Institute of Forensic Sciences should be created. This institute was a suggestion made in the National Academy of Science’s 2009 report ​​Strengthening Forensic Science in the United States: A Path Forward. According to the report, this institution would consist of unbiased scientists with no connections to law enforcement or crime labs, who would review different forensic science methods and determine how each could be improved.

To end the interview, Rakoff stated that despite the flaws and need for reform he’s seen in the criminal justice system, he’s optimistic for the future.

To listen to or read the transcript from Episode 7: Shaky Science in the Courtroom, visit