A Study on Improving Forensic Decision Making will be the Topic of CSAFE’s February Webinar

Figure 2 from the study shows sources of cognitive bias in sampling, observations, testing strategies, analysis and/or conclusions, that impact even experts. These sources of bias are organized in a taxonomy of three categories: case-specific sources (Category A), individual-specific sources (Category B) and sources that relate to human nature (Category C).

A new study that proposes a broad and versatile approach to strengthening expert decision making will be the focus of an upcoming Center for Statistics and Applications in Forensic Evidence (CSAFE) webinar.

The webinar, Improving Forensic Decision Making: A Human-Cognitive Perspective, will be held Thursday, Feb. 17 from 12–1 p.m. CST. It is free and open to the public.

Itiel Dror
Itiel Dror

During the webinar, Itiel Dror, a cognitive neuroscience researcher from the University College London, will discuss his journal article, Linear Sequential Unmasking–Expanded (LSU-E): A general approach for improving decision making as well as minimizing noise and bias. The article was published in Forensic Science International: Synergy and co-authored by Jeff Kukucka, associate professor of psychology at Towson University.

In the article, the authors introduce Linear Sequential Unmasking (LSU-E), an approach that can be applied to all forensic decisions, and also reduces noise and improves decisions “by cognitively optimizing the sequence of information in a way that maximizes information utility and thereby produces better and more reliable decisions.”

From the Abstract:

In this paper, we draw upon classic cognitive and psychological research on factors that influence and underpin expert decision making to propose a broad and versatile approach to strengthening expert decision making. Experts from all domains should first form an initial impression based solely on the raw data/evidence, devoid of any reference material or context, even if relevant. Only thereafter can they consider what other information they should receive and in what order based on its objectivity, relevance, and biasing power. It is furthermore essential to transparently document the impact and role of the various pieces of information on the decision making process. As a result of using LSU-E, decisions will not only be more transparent and less noisy, but it will also make sure that the contributions of different pieces of information are justified by, and proportional to, their strength.

To register for the February webinar, visit https://forensicstats.org/events/.

The CSAFE Spring 2022 Webinar Series is sponsored by the National Institute of Standards and Technology (NIST) through cooperative agreement 70NANB20H019.

NIST Releases New Report on Human Factors’ Role in Handwriting Evaluation

pen and handwritten text

All human activities carry a risk of error, and handwriting examination is no exception. To reduce errors in this field, NIST convened the Expert Working Group for Human Factors in Handwriting Examination. This expert panel sponsored by NIJ and NIST examined strategies to improve handwriting evaluation methods and outline best practices.

The Group produced a new report, Forensic Handwriting Examination and Human Factors: Improving the Practice Through a Systems Approach. The document takes a closer look at how human factors impact all aspects of handwriting examination, from documenting discriminating features, reporting results and testifying in court. 

In the report, you’ll also find a discussion of education, training, certification, and the role of quality assurance, quality control, and management in reducing errors.

CSAFE Resources for Improving Handwriting Evaluation 

CSAFE researchers are also working to improve objectivity and reduce errors in handwriting analysis. Our work aims to rigorously assess the role of complexity in signature analysis and relate complexity to examiner performance. We are also developing open-source software and publicly available statistical algorithms for writing comparison to help handwriting examiners integrate quantitative approaches in their work.

Handwriting Database

The CSAFE Handwriting Database is an interactive, public database designed for the development of statistical approaches to forensic handwriting evaluations.  


CSAFE automatic matching algorithms provide objective and reproducible scores as a foundation for a fair judicial process. This R package utilizes a variety of functions to identify letters and features from handwritten documents.


How Much Information is Too Much? Explore the Role of Contextual Bias in Forensic Science

Forensic Examiners in Laboratory

Is it possible for a forensic examiner to receive too many details about a piece of evidence? Contextual information such as where the evidence was collected and the environment at the scene may be helpful, or it could create unintentional bias.

Dr. William Thompson of the University of California, Irvine collaborated with the National Institute of Justice to examine contextual bias. In a report published in April 2019, Thompson explores strategies for ensuring forensic examiners have enough detail to perform a rigorous scientific examination while also shielding them from potentially biasing contextual information.

Thompson Explored Three Potential Solutions:

  • The Case Manager Model:
    • Functions in the laboratory are separated between case managers and examiners. Managers are fully informed about context, while analysts are provided with only the information needed for specific analytical tasks
  • Sequential Unmasking:
    • Sequencing the order of various analytic tasks to ensure examiners make key analytics judgments before being exposed to biasing information
  • Blind Re-Examination:
    • Key judgments of an initial non-blind examiner are replicated by a second examiner who has not been exposed to potentially biasing information.

Learn more about these strategies, and the role contextual information plays in an examiner’s decision-making process in “Developing Effective Methods for Addressing Contextual Bias in Forensic Science.”

For an inside look at bias, review our interview with CSAFE psychologists. The Innocence Project is also tackling the effects of bias in forensic science. Find more details in our guest post.

Human Factors in Forensic Science: CSAFE Researchers Explain Cognitive Psychology’s Role

Is the field of science-based solely on logic and facts? A closer look reveals that science is not always as systematic and foolproof as we may think.

Scientists are humans, not robots. As such, the field of science has the potential to be compromised by human error, bias and other cognitive factors.

CSAFE researchers and psychologists Dr. Daniel Murrie and Dr. Sharon Kelley from the University of Virginia describe how human factors can influence the accuracy of scientific work as a whole, and the specific impact they can have on forensic science.

Defining Human Factors

Dr. Murrie explains that human factors are relevant any time that the human mind or behavior is part of the scientific process. “Human factors, including cognitive bias, can influence how we collect and analyze data, or how we communicate the findings,” he said.

The human brain is powerful and typically steers us in the right direction.

“Our minds are very efficient and that usually serves us well,” Murrie said. “Our brains develop many shortcuts or heuristics that help us make reasonably good decisions fast.”

While this approach to decision making seems practical and beneficial, it has a downside.

“There are a few times when that cognitive infrastructure can lead us to take short cuts or jump to conclusions,” Murrie said. “This can leave us vulnerable to bias in ways that aren’t helpful to science, accuracy or objectivity.”

Human Factors in Forensic Evidence Analysis

The 2009 NAS report calling for reform in forensic science has led to more awareness of human factors and driven new research on cognitive bias in evidence analysis.

For instance, when a fingerprint or shoeprint examiner compares the print of a suspect to a print from the crime scene, there is potential for human factors to bias the examiner’s decision on a match.

Dr. Kelley explains how.

“General social and cognitive psychology research indicates that (A) humans often see what they expect to see and that (B) humans tend to seek out and interpret information in a way that supports their pre-existing beliefs,” she said.

For example, forensic science examiner may have had an opinion about the guilt or innocence of a suspect before even beginning the examination. Whether intentional or not, it could lead to biased results.

Dr. Kelley emphasizes that forensic scientists must be aware of potential bias before expressing opinions or decisions on the outcome of evidence analysis.

Why Is Awareness of Bias, not Enough?

“The good news is that awareness of biases in forensic science is probably at an all-time high. The bad news is that people don’t quite know what to do with this new awareness,” Murrie said.

One concern from recent research is the “bias blind spot,” as cognitive psychologists call it.

“People generally recognize that bias is a problem, but they only see it in others—not themselves,” Murrie said.

Kelley explains that for those who do recognize their own biases, it’s hard to change on your own.

“Introspecting and knowing about the bias and then just trying hard not to be biased is not enough,” Kelley said. “We know from research that these biases often aren’t conscious and you can’t just scan yourself and check for them. Biases still creep into our decision making.”

Instead of squinting your eyes and focusing hard not to be biased, Kelley says procedural and systematic changes are needed.

Strategies to Lessen the Impact of Human Factors in Crime Labs

According to Kelley, crime labs are a very heterogeneous group. They differ in their understanding of cognitive bias and strategies to combat the issue.

So how can researchers like Murrie and Kelley help crime labs reduce the impact of human factors in their investigations?

Two strategies CSAFE is working on to reduce bias are blind verification procedures and context management.

Blind verification procedures serve as checks and balances when analyzing evidence.  In this method, a second examiner reviews a case with no information about what the first examiner concluded. Crime laboratories then have two independent decisions to compare. When the two examiners agree, there is more confidence that the analysis is accurate.

Context management involves limiting unnecessary contextual information about the suspect or the crime scene that is irrelevant to the evidence analysis task. For example, when comparing a set of fingerprints, the examiner doesn’t need to know the race or criminal record of the suspect, or even the results of DNA analyses, to do their job. Reducing potentially biasing information increases objectivity in evidence analysis.

Read more about how CSAFE research is addressing context management in crime laboratories.