As new probabilistic and statistical methods are developed they must be implemented by the forensic community. CSAFE is focused on research to facilitate the implementation of methods and identify best practices for their use. Relevant research topics include finding optimal ways to communicate statistical conclusions –– both verbally and graphically, understanding the barriers to widespread implementation, and best practices for forensic practitioners, lawyers and judges.
William C Thompson
University of California Irvine
University of California Irvine
Additional Team Members
Hal S. Stern
Statistical evidence can be presented to attorneys, judges and jurors in a range of ways, from verbal descriptions of the weight of evidence to numerical scores to more complicated statistical summaries. CSAFE researchers are conducting studies with various forms of testimony and conclusions to determine if these new forms of testimony are better suited to minimize misinterpretation.
The goal of this project is to better understand how to convey forensic information to laypeople in a way that is accurate and comprehensible. Our research focused initially on terms used to convey forensic conclusions and how jurors understand them. We have studied how to convey proficiency and error rate information and begun to move towards more detailed mock trial scenarios — such as studies of competing experts testifying at trial.
First, in our new work, we need to better understand as a foundational matter what informs jurors regarding the strengths and limits of forensic evidence. Our prior work has given us an initial picture of this problem. In the next set of studies, we need more realistic designs and we need to keep up with developments in the field. We will examine new ways of conveying forensic information to lay jurors as the field moves towards new standards for terminology, including as developed by OSAC, and in some settings, the use of quantitative methods and conclusions. We are also moving towards more detailed designs, including with videos of mock courtroom testimony, and perhaps jury deliberation, to make for more realistic studies. We will examine what explains the varying weight that laypeople place on forensic testimony to better understand how to explain the strengths and limits of that evidence to them.
Second, we need to study new interventions that might change how laypeople evaluate forensic evidence. We will examine newly developed language, such as terminology developed by OSAC, language required by judges in their rulings, and its impact on lay decisionmakers. We need to study what effect jury instructions might have on visual presentations. Relatedly, in addition to studying lay decisionmaking, we will also assess what lawyers currently understand (and do not understand) about the evidence forensic experts currently present (or may, in the future, choose to present) in reports and testimony, so that we can better assess the role that lawyers play in presentation of forensic evidence. Similarly, we will survey judges to better understand their role and needs in this process (as also discussed in ED II). Research on how lawyers understand and misunderstand the language in forensic science reports may help forensic scientists develop more effective reporting language. And this work may help identify undesirable courtroom practices that might mislead jurors and help inform policy regarding how lawyers should conduct themselves at trial. Ultimately, we plan to develop model training for defense lawyers and judges that will also be of value to forensic scientists as they prepare for testimony and interact with legal professionals.
Third, based on this research, we will develop recommendations for how to better convey strengths and limits of forensic evidence in testimony, to inform new standards for such testimony. We will also develop recommendations for judicial instructions and evidentiary standards regarding forensic conclusions. Finally, we will make recommendations for work that defense lawyers and prosecutors can do to better educate jurors regarding strengths and limits of forensic evidence.
It is a key goal of CSAFE to better understand the impediments to adoption of probabilistic methods among forensic science practitioners and members of the legal community, so that they can be overcome and probabilistic methods can be effectively implemented. It is important to study attitudes of practitioners towards probabilistic analyses including both the benefits and disadvantages that they perceive. CSAFE researchers achieve this insight through surveys, interviews and observations of forensic practitioners in order to assess obstacles and methods to overcome them.
To be useful, the statistical applications developed by CSAFE will have to be adopted by forensic scientists and forensic service providers (FSPs). It is well-known that many forensic scientists and FSPs are skeptical, or even resistant, to the adoption of statistical applications. To facilitate the adoption of statistical applications, we need a better understanding of the organizational cultures of the FSPs that we hope will adopt them. Such understanding can be facilitated by a sociology of forensic science. Further, we also need a better sociological understanding of the discipline of forensic statistics. Many non-statisticians profess themselves bewildered by forensic statistics. While forensic statistics has made efforts to account for itself, it will be helpful to complement these with a sociological account, from an external perspective, about the discipline. An account that locates forensic statistics in its historical and sociological context can only enhance non-statisticians’ understanding of the discipline and nature of the applications it is seeking to implement.
Sociology of science is a well-established discipline that uses the tools of the social sciences to understand the making of scientific knowledge. While most work in sociology of science has focused on more traditional academic disciplines, like physics, biology, medicine, and engineering, there has long been a thriving line of research on forensic science. Sociologists of science are particularly drawn to forensic science because of its proximity to law, which brings two powerful truth-making social institutions (science and law) into close contact.
While there has been some work on the sociology of forensic science, there has been almost no work on the sociology of forensic statistics.
By sociologically analyzing the impact of statistical application on forensic laboratories and the reactions of forensic scientists to statistical applications, the project will allow forensic scientists to progress from a “local” perspective informed by their own experiences and personal interactions to a more “global” perspective informed by the experiences of the discipline as a whole with statistical applications.
The research will draw on the standard tools in the sociology of science. These include social scientific methods, such as interviews, participant-observation and ethnography, as well as methods drawn more from history of science, such analyses of scholarly debates conducted through published literature.
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Using mixture models to examine group difference among jurors: an illustration involving the perceived strength of forensic science evidence
Published: 2021 | By: Naomi Kaplan-Damary
The way in which jurors perceive reports of forensic evidence is of critical importance, especially in cases of forensic identification evidence that require examiners to compare items and assess whether they originate from a common source. The current study discusses…
Published: 2021 | By: Gregory Mitchell
The present study examined whether a defense rebuttal expert can effectively educate jurors on the risk that the prosecution's fingerprint expert made an error. Using a sample of 1716 jury-eligible adults, we examined the impact of three types of rebuttal…
The 2021 Field Update was held June 14, 2021, and served as the closing to the first year of CSAFE 2.0. CSAFE brought together researchers, forensic science partners and interested community members to highlight the organization’s achievements, identify areas for…
This CSAFE webinar was held on May 25, 2021. Presenter: Henry Swofford Ph.D. Candidate – University of Lausanne Presentation Description: Over the years, scientific and legal scholars have called for the implementation of algorithms (e.g., statistical methods) in forensic science…
Published: 2021 | By: Brandon L. Garrett
In criminal cases, forensic science reports and expert testimony play an increasingly important role in adjudication. More states now follow a federal reliability standard, which calls upon judges to assess the reliability and validity of scientific evidence. Little is known…
This CSAFE symposium was held on March 12, 2021. Presenter: Professor Edward Imwinkelried Edward L. Barrett, Jr. Professor of Law Emeritus, University of California - Davis School of Law Panelists: Professor Ric Simmons, The Ohio State University, Moritz College of…
Published: 2020 | By: William E. Crozier
Forensic testimony plays a crucial role in many criminal cases, with requests to crime laboratories steadily increasing. As part of efforts to improve the reliability of forensic evidence, scientific and policy groups increasingly recommend routine and blind proficiency tests of…
Published: 2020 | By: Brandon L. Garrett
Objectives: Firearms experts traditionally have testified that a weapon leaves “unique” toolmarks, so bullets or cartridge casings can be visually examined and conclusively matched to a particular firearm. Recently, due to scientific critiques, Department of Justice policy, and judges’ rulings,…
This CSAFE Center Wide webinar was presented on December 8, 2020 by: Brandon Garrett – L. Neil Williams Professor of Law, Faculty Director at the Wilson Center for Science and Justice Nicholas Scurich – Associate Professor of Criminology, Law &…
Published: 2018 | By: Brandon Garrett
Few can say, "I told you so," to our entire criminal justice system. Being right about what is wrong with the use of evidence in criminal cases is not a bad thing, but being able to influence the growing response…
Published: 2020 | By: Simon Cole
Forensic evidence reporting shows a high degree of adherence to prevailing disciplinary standards. Probabilistic reporting of forensic results remains rare. Probabilistic reports were mostly subjective verbal assignments of posterior probabilities.
How Can a Forensic Result Be a ‘Decision’? A Critical Analysis of Ongoing Reforms of Forensic Reporting Formats for Federal Examiners
Published: 2020 | By: Simon A. Cole
The decade since the publication of the 2009 National Research Council report on forensic science has seen the increasing use of a new word to describe forensic results. What were once called “facts,” “determinations,” “conclusions,” or “opinions,” are increasingly described…
Published: 2019 | By: Callan Hund
A blind quality control (QC) program was successfully developed and implemented in the Toxicology, Seized Drugs, Firearms, Latent Prints (Processing and Comparison), Forensic Biology, and Multimedia (Digital and Audio/Video) sections at the Houston Forensic Science Center (HFSC). The program was…
The 2020 All Hands Meeting was held May 12 and 13, 2020 and served as the closing to the last 5 years of CSAFE research and focused on kicking off new initiatives for the next phase of the center, CSAFE…
Published: 2020 | By: Brandon Garrett
Forensic examiners regularly testify in criminal cases, informing the jurors whether crime scene evidence likely came from a source. In this study, we examine the impact of providing jurors with testimony further qualified by error rates and likelihood ratios, for…
Published: 2020 | By: Brandon L. Garrett
Supreme Court Justice Louis Brandeis famously wrote that states can be laboratories for experimentation in law and policy. Disappointingly, however, the actual laboratories that states and local governments run are not a home for experimentation. We do not have adequate…
Published: 2019 | By: Brett O. Gardner
In response to research demonstrating that irrelevant contextual information can bias forensic science analyses, authorities have increasingly urged laboratories to limit analysts' access to irrelevant and potentially biasing information (Dror and Cole (2010) ; National Academy of Sciences (2009) ;…
Published: 2019 | By: Daniel C. Murrie
Every scientific technique features some error, and legal standards for the admissibility of scientific evidence (e.g., Daubert v. Merrill Dow Pharmaceuticals, Inc., 1993; Kumho Tire Co v. Carmichael, 1999) guide trial courts to consider known error rates. However, recent reviews…
Published: 2019 | By: Jackeline Moral
Declared proficiency tests are limited in their use for testing the performance of the entire system, because analysts are aware that they are being tested. A blind quality control (BQC) is intended to appear as a real case to the…
Published: 2018 | By: Alex Biedermann
Big changes are occurring in forensic science, particularly among experts who compare the patterns found in fingerprints, footwear impressions, toolmarks, handwriting, and the like. Forensic examiners are reaching conclusions in new ways and changing the language they use in reports…
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