Forensic Science Disciplines Research Articles

A global survey of the attitudes and perspectives of cognitive bias in forensic anthropology

It is now well established that decision making can be susceptible to cognitive bias in a broad range of fields, with forensic science being no exception. Previously published research has revealed a bias blind spot in forensic science where examiners do not recognise bias within their own domain. A survey of 101 forensic anthropology practitioners (n = 52) and students (n = 38) was undertaken to assess their level of awareness of cognitive bias and investigate their attitudes towards cognitive bias within forensic anthropology. The results revealed that the forensic anthropology community (∼90%) had a high level of awareness of cognitive bias. Overall ∼89% expressed concerns about cognitive bias in the broad discipline of forensic science, their own domain of forensic anthropology, and in the evaluative judgments they made in reconstruction activities, identifying a significant reduction in the bias blind spot. However, more than half of the participants believed that bias can be reduced by sheer force of will, and there was a lack of consensus about implementing blinding procedures or context management. These findings highlight the need to investigate empirically the feasibility of proposed mitigating strategies within the workflow of forensic anthropologists and their capabilities for increasing the transparency in decision making.

Reliability of ordinal outcomes in forensic black-box studies

Forensic science disciplines such as latent print examination, bullet and cartridge case comparisons, and shoeprint analysis, involve subjective decisions by forensic experts throughout the examination process. Most of the decisions involve ordinal categories. Examples include a three-category outcome for latent print comparisons (exclusion, inconclusive, identification) and a seven-category outcome for footwear comparisons (exclusion, indications of non-association, inconclusive, limited association of class characteristics, association of class characteristics, high degree of association, identification). As the results of the forensic examinations of evidence can heavily influence the outcomes of court proceedings, it is important to assess the reliability and accuracy of the underlying decisions. “Black box” studies are the most common approach for assessing the reliability and accuracy of subjective decisions. In these studies, researchers produce evidence samples consisting of a sample of questioned source and a sample of known source where the ground truth (same source or different source) is known. Examiners provide assessments for selected samples using the same approach they would use in actual casework. These studies often have two phases; the first phase comprises of decisions on samples of varying complexities by different examiners, and the second phase involves repeated decisions by the same examiner on a (usually) small subset of samples that were encountered by examiners in the first phase. We provide a statistical method to analyze ordinal decisions from black-box trials with the objective of obtaining inferences for the reliability of these decisions and quantifying the variation in decisions attributable to the examiners, the samples, and statistical interaction effects between examiners and samples. We present simulation studies to judge the performance of the model on data with known parameter values and apply the model to data from a handwritten signature complexity study, a latent fingerprint examination black-box study, and a handwriting comparisons black-box study.

Scientific guidelines for evaluating the validity of forensic feature-comparison methods

When it comes to questions of fact in a legal context—particularly questions about measurement, association, and causality—courts should employ ordinary standards of applied science. Applied sciences generally develop along a path that proceeds from a basic scientific discovery about some natural process to the formation of a theory of how the process works and what causes it to fail, to the development of an invention intended to assess, repair, or improve the process, to the specification of predictions of the instrument’s actions and, finally, empirical validation to determine that the instrument achieves the intended effect. These elements are salient and deeply embedded in the cultures of the applied sciences of medicine and engineering, both of which primarily grew from basic sciences. However, the inventions that underlie most forensic science disciplines have few roots in basic science, and they do not have sound theories to justify their predicted actions or results of empirical tests to prove that they work as advertised. Inspired by the “Bradford Hill Guidelines”—the dominant framework for causal inference in epidemiology—we set forth four guidelines that can be used to establish the validity of forensic comparison methods generally. This framework is not intended as a checklist establishing a threshold of minimum validity, as no magic formula determines when particular disciplines or hypotheses have passed a necessary threshold. We illustrate how these guidelines can be applied by considering the discipline of firearm and tool mark examination.

A model of evaluative opinion to encourage greater transparency and justification of interpretation in post-mortem forensic toxicology.

Over the past decades, the calls to improve the robustness of interpretation in forensic science have increased in magnitude. Forensic toxicology has seen limited progress in this regard. In this work, we propose a transparent interpretive pathway for use in post-mortem forensic toxicology cases. This process allows the selection of the interpretive methodology based on the amount of previous information that is available for the substance(s) in question. One approach is an assessment of various pharmacological and circumstantial considerations resulting in a toxicological significance score (TSS), which is particularly useful in situations where limited information about a substance is available. When there is a robust amount of case data available, then a probabilistic approach, through the evaluation of likelihood ratios (LRs) by the toxicologist and of prior probabilities by the fact-finder, is utilized. This methodology provides a transparent means of making an interpretive decision on the role of a drug in the cause of death. This will allow the field of forensic toxicology to take a step forward in using best practice in evaluative reporting, a tool already used by many other forensic science disciplines.

Bloodstain pattern analysis & Bayes: A case report

The findings from a bloodstain pattern analysis (BPA) may assist in formulating or falsifying scenarios that are considered in the investigative stages of a criminal investigation. When a case proceeds to trial the bloodstain pattern expert may be asked about the relevance of their findings given scenarios that are proposed by the prosecution and defense counsel. Such opinions provided by an expert are highly relevant to police investigation or legal proceedings, but the reasoning behind the opinion or implicit assumptions made by the expert may not be transparent.A proper framework for the evaluation of forensic findings has been developed since the late twentieth century, based on the hierarchy of propositions, Bayesian reasoning and a model for case assessment and interpretation. This framework, when implemented in casework, mitigates some of the risks of cognitive biases, and makes the reasoning and scientific basis for the opinion transparent. This framework is broadly used across forensic science disciplines. In this paper we describe its application to the field of BPA using a case example from the Netherlands Forensic Institute (NFI).

Towards more relevance in forensic science research and development

Many different issues have been identified in forensic science for more than 10 years. While quality management has often been suggested as a path forward, research is generally considered as an essential part of the solution. Through an overview of current forensic science research, this paper aims at evaluating if and how research answer the challenges forensic science is currently facing. While forensic related publications have massively increased over the years, approximately half of the publications were published in non-forensic sources, indicating that forensic science research tends to be led by other disciplines. Over the years, forensic science research has remained largely oriented towards methodological and technological development rather than relevance to the forensic science discipline and practice. Practical implementation of the techniques is rarely discussed from a forensic perspective, and thus research rarely move from the “proof-of-concept” stage to its utilisation in case investigation. The digital transformation also generated a massive increase of data, making it challenging to find the relevant pieces of information in the mass of “forensic” publications available on-line. Thus, we propose to refocus forensic science research on forensic fundamental and practical questions to strengthen the discipline and its impact on crime investigation and security issues. Our propositions represent an incentive to further discuss forensic science research and knowledge transmission through the definition of a common culture within the community, focusing on common fundamental knowledge such as a better understanding of the concept of trace and its case-based information content.

Forensic intelligence teaching and learning in higher education: An international approach

Over the years, forensic science has primarily positioned itself as a service provider for the criminal justice system, following the dominant and traditional reactive law enforcement model. Unfortunately, this focus has limited its capacity to provide knowledge about crime systems and to support other forms of policing styles through forensic intelligence. Although forensic intelligence research has steadily developed over the last few years, it is rarely covered in the core of academic teaching and research programs. Developing forensic intelligence programs would empower graduates with an awareness of forensic intelligence meaning and models, creating great opportunities to shape their future professional activities and progressively shift the dominant paradigm through a bottom-up approach. In this article, the teaching and learning strategies in forensic intelligence developed at the University of Lausanne (Switzerland) and adapted at the University of Technology Sydney (Australia) and the Université du Québec à Trois-Rivières (Canada) are presented. The objective behind the strategy is to reflect on and work on real case scenarios using a progressive teaching and learning approach that builds upon the theory and practical exercise putting students in real-life situations. Through this innovative learning process, students move away from the Court as the sole end purpose of forensic science. They learn to adopt different roles, adopt a proactive attitude as well as work individually and collaboratively. This teaching and learning strategy breaks the current silos observed in the forensic science discipline by focusing on processes and critical thinking. It can be foreseen, through the evolution of crime and policing models, that the learning and teaching strategy described in this article offers and will offer the students with many new job opportunities. The article concludes with the advantages that such teaching and learning programs in forensic intelligence bring to the forensic science community.

Registered reports in forensic science.

Research assessing the validity and reliability of many forensic science disciplines has been published; however, the quality of this research varies depending on the methodologies employed. This was a major point of contention with the United States' President's Council of Advisors on Science and Technology, who recognized the existing literature but found the majority lacking because of methodological issues. Questionable scientific methodologies have undermined the forensic science community's ability to defend the scientific foundations and examination protocols used to examine evidence in criminal cases. Such scientific failures have significant legal implications. Registered reports, which strengthen the quality of scientific research and reliability of laboratory protocols, can provide transparency, validity and a stronger scientific foundation for forensic science.

POLICING FORENSIC EVIDENCE

POLICING FORENSIC EVIDENCE

MULTIDISCIPLINARY FORENSIC ANALYSIS ACTS AS AN EYEWITNESS TO LINK THE CRIME- CULPRIT- CRIME SCENE- DECEASED. - AN INTERESTING CASE STUDY

: Different types of evidence found on the crime scene can be classified into biological, chemical, physical, and digital. Biological evidence is a person's body fluids, hair, tissue, etc, chemical evidence is any material used in the crime such as poison, drugs, inflammable substances, chili powder, etc, objects such as weapons, soil, fibers, broken glass piece, etc constitute physical evidence and digital evidence includes CCTV footage, online purchase history of weapons, mobile phones, pen drive, etc. These evidences are analyzed by different disciplines of forensic science like Biology, DNA, Chemistry, Toxicology, Ballistics, and Cyber. In a gruesome murder that took place in broad daylight, the victim's car was surrounded by a few people at a traffic signal. Car's window glasses were broken and he was brutally murdered using sharp-edged weapons. Forensic Science Laboratory helped the investigating agency to collect evidences at the crime scene. Almost every discipline of forensic science was involved in the analysis of the evidences found (biological, chemical, physical and digital). Detection, assessment and interpretation of the evidences aided to fix the crime scene, the presence of the accused on the crime scene and his involvement in the crime. This multidisciplinary analysis freed the investigating agency from dependency on eyewitnesses. Thus, scientific evidence from various disciplines of forensic science contributed their part and completed the whole picture of murder.

The Reliability of Expert Evidence in Canada

This paper analyzes Canada’s common law as it currently stands regarding expert evidence and key inquiries and reports on expert evidence and wrongful convictions done in Canada and on forensic science. The analysis will demonstrate how Canada’s laws and practices have not gone far enough to ensure expert evidence is reliable in order to protect innocent citizens from wrongful conviction. I propose that to truly safeguard against the admission of improper expert evidence in trials Canada must (1) heighten the standard expert evidence must meet to be considered reliable and increase a judge’s role as gatekeeper (2) foster a system of peer-reviewed research, training, accreditation, and accountability in forensic science disciplines in Canada, and (3) ensure that all legal actors (i.e., police, lawyers, and judges) receive continued training on best forensic science practices and their limits and have free access to information and education on forensic science disciplines when needed. Systemic changes in forensic science disciplines in Canada, continued education in forensic sciences for legal actors, and changes in the law of reliability of evidence are necessary to prevent improper expert evidence from continuing to contribute to wrongful convictions. This paper concludes by with a case study evaluating how the proposed systemic changes could have made a difference in a real-world case where expert evidence was flawed.

The Need for Standards Unification in Forensic Laboratory Practices: Protocol for Setting Up the Arab Forensic Laboratories Accreditation Center.

Background Despite the recent trend toward developing and applying quality control measures in the forensic science disciplines, there is a heightened interest to efforts to ameliorate disparate quality among laboratories through the enforcement of standards and best practices.Objective This protocol aims to set up the Arab Forensic Laboratories Accreditation Center (AFLAC) to act as a key driving legal force for accreditation of the different forensic laboratories in the Arab region.Methods Upon its development, the Forensic Laboratory-Arabian Gate (FLAG) platform will serve as a preliminary stage for the AFLAC, and 2 preparatory steps will be achieved through the FLAG platform: the first one is a scoping study to analyze the international guidelines regarding the forensic laboratory practices in different specialties, and the second one is mapping surveys to explore how the international and national guidelines are translated into practice in Arab forensic laboratories. Development of the Arab forensic laboratories accreditation center will be initiated by building the AFLAC quality management system, which comprises formation of the forensic science committees to achieve the standards required for accreditation in each discipline. This will be followed by the attainment of regional accreditation recognition of the Arab Accreditation Cooperation (ARAC) and the International Laboratory Accreditation Cooperation. This recognition necessitates achieving International Organization for Standardization/International Electrotechnical Commission 17011 standard requirements prior to official application to the ARAC.Results The first phase of our work (the FLAG platform) began in February 2022 and is expected to end in December 2022. The FLAG platform was proposed to the Arab Society of Forensic Sciences and Forensic Medicine in March 2022, and we received approval to host this web development project. Subsequent phases are anticipated to begin in January 2023 and are expected to end in 2025.Conclusions This work describes our approach to provide a valuable tool for forensic laboratory accreditation services to promote the best practice and its consistency in the field of forensic sciences in the Arab region.International Registered Report Identifier (IRRID)PRR1-10.2196/36778

Comparison of portable and benchtop electrochemical instruments for detection of inorganic and organic gunshot residues in authentic shooter samples

Analysis of gunshot residue currently lacks effective screening methods that can be implemented in real time at the crime scene. Historically, SEM-EDS has been the standard for analysis; however, advances in technology have brought portable instrumentation to the forefront of forensic science disciplines, including the screening of GSR. This study proposes electrochemical methods with disposable screen-printed carbon electrodes for GSR screening at the laboratory and points of care due to their rapid, cost-efficient, and compact platform. GSR residues were extracted from typical aluminum/carbon adhesive collection stubs and analyzed via square-wave anodic stripping voltammetry. Benchtop and portable electrochemical instruments were compared for the assessment and classification of authentic shooter samples by monitoring a panel of inorganic and organic GSR elements and compounds including lead, antimony, copper, 2,4-dinitrotoluene, diphenylamine, nitroglycerin, and ethyl centralite. The evaluation included the assessment of figures of merit and performance measures from quality controls, nonshooter, and shooter data sets. Samples collected from the hands of 200 background individuals (nonshooters), and shooters who fired leaded ammunition (100) and lead-free ammunition (50) were analyzed by the benchtop and portable systems with accuracies of 95.7% and 96.5%, respectively. The findings indicate that electrochemical methods are fast, sensitive, and specific for the identification of inorganic and organic gunshot residues. The portable potentiostat provided results comparable with the benchtop system, serving as a proof-of-concept to transition this methodology to crime scenes for a practical and inexpensive GSR screening that could reduce backlogs, improve investigative leads, and increase the impact of gunshot residues in forensic science.

Probabilistic reporting and algorithms in forensic science: Stakeholder perspectives within the American criminal justice system

In recent years, there have been efforts to promote probabilistic reporting and the use of computational algorithms across several forensic science disciplines. Reactions to these efforts have been mixed—some stakeholders argue they promote greater scientific rigor whereas others argue that the opacity of algorithmic tools makes it challenging to meaningfully scrutinize the evidence presented against a defendant resulting from these systems. Consequently, the forensic community has been left with no clear path to navigate these concerns as each proposed approach has countervailing benefits and risks. To explore these issues further and provide a foundation for a path forward, this study draws on semi-structured interviews with fifteen participants to elicit the perspectives of key criminal justice stakeholders, including laboratory managers, prosecutors, defense attorneys, judges, and other academic scholars, on issues related to interpretation and reporting practices and the use of computational algorithms in forensic science within the American legal system.

The benefits of errors during training

Errors are generally not thought of as a positive thing – not in society at large, and especially not in forensic science. However, there is a large body of literature in the field of cognitive science (particularly from psychology and education research) that highlights the benefits that can be gained from using errors made in training to improve learning. Although none of these studies was done directly in the forensic science disciplines, there are nonetheless lessons to be learned about how errors may most effectively be used to maximize their benefits to learning. This article presents an overview of the literature on learning from errors and suggests principles that may be of benefit to forensic science today, as well as suggesting areas where specific research may be of benefit to forensic science in the future.

The biasing impact of irrelevant contextual information on forensic odontology radiograph matching decisions

The potential biasing effect of irrelevant context information on the forensic odontology method of radiograph-based identification has never been empirically investigated despite being a recognized problem in other forensic science disciplines. This study examines the effect of irrelevant context information on the probability judgment of match (JOM) of practicing forensic odontologist and dentist participants who were asked to match pairs of dental radiographs supplemented with irrelevant case information.The irrelevant case information contained domain task-irrelevant context information which varied in strength (strong or weak). It suggested either supportive or contradictory bias relative to the actual match status of the radiograph pairs. The dental radiographs consisted of verified match and non-match radiographs pairs sampled and de-identified from actual forensic cases. Changes in accuracy and JOM between supportive and contradictory contexts conditions revealed a contextual bias. Mixed model analysis showed that strong supportive context increased the odds ratio of correct decisions by a factor of 2.4 [1.23, 4.46]; p = 0.0097. Consistent with the biasing effect, the JOM score differences between strong supportive and contradictory irrelevant context information were 1.03 and 0.43 respectively for the non-match and match decisions. The direction of context suggestion (p = 0.0067), the radiograph match status (p = 0.014), and their interactions (p = 0.0061), were all found to impact the participants’ decision. The weak context information was not strong enough to have a significant effect on accuracy or JOM scores.This study demonstrates that radiograph match judgment is affected and can be biased by strong irrelevant contextual information.

What does a digital forensics opinion look like? A comparative study of digital forensics and forensic science reporting practices

This study explores digital forensics (DF) reporting practices and compares the results with other forensic science disciplines. Forty reports were obtained from a quasi-experiment involving DF examiners, and a quantitative content analysis was performed to determine which conclusion types they applied and which content they included with relevance to the credibility of the reported results. A qualitative analysis was performed to examine the certainty expressions used in the conclusions. The results were compared to a study of eight forensic science disciplines performed by Bali et al. [24,26]. The results show that the DF examiners tend to present their conclusions either as Categorical conclusion or Strength of support (SoS) conclusion types and that they address source, activity, and offence level issues in their conclusions. The content analysis indicates deficiencies in DF reporting practices, and several of the challenges seem to be shared with other FS disciplines. The analysis of certainty expressions showed that a plethora of expressions was used, and that they lacked reference to an established framework. The results indicate that more research on DF evaluation and reporting practices is necessary and justifies a need for enhanced focus on quality control and peer review within the DF discipline.

A hierarchy of expert performance as applied to forensic anthropology.

Due to their medicolegal repercussions, forensic anthropology conclusions must be reliable, consistent, and minimally compromised by bias. Yet, a synthetic analysis of the reliability and biasability of the discipline's methods has not yet been conducted. To do so, this study utilized Dror's (2016) hierarchy of expert performance (HEP), an eight-level model aimed at examining intra- and inter-expert reliability and biasability (the potential for cognitive bias) within the literature of forensic science disciplines. A systematic review of the forensic anthropology literature was conducted (1972-present), including papers published in the American Journal of Physical Anthropology, Forensic Anthropology, Forensic Science International, and the Journal of Forensic Sciences and Anthropology Section abstracts published in the Proceedings of the Annual Meeting of the AAFS which matched keywords such as "forensic anthropology," "bias," "reliability," "cognition," "cognitive," or "error." The resulting forensic anthropology HEP showcases areas that have ample research and areas where more research can be conducted. Specifically, statistically significant increases in reliability (p<0.001) and biasability (p<0.001) publications were found since 2009 (publication of the NAS report). Extensive research examined the reliability of forensic anthropological observations and conclusions (n=744 publications). However, minimal research investigated the biasability of forensic anthropological observations and conclusions (n=20 publications). Notably, while several studies demonstrated the biasing effect of extraneous information on anthropological morphological assessments, there was no research into these effects on anthropological metric assessments. The findings revealed by the forensic anthropology HEP can help to guide future research, ultimately informing the development and refinement of best-practice standards for the discipline.

Defining ‘service levels’ for digital forensic science organisations

As demand for support from the digital forensic science discipline by criminal justice systems continues to remain high, there is a need to ensure that this field can sustain its valuable contribution to many investigations. With well documented backlogs and the presence of relevant digital behaviour documented on devices in many criminal cases means that there is a need to ensure the field's resources can be deployed effectively. It is suggested that law enforcement digital forensic science organisations could consider the deployment of a system of ‘Service Levels’, designed to transparently outline the different types of forensic capability that can be deployed within a given investigative scenario. This work defines and describes a set of seven ‘Service Level’ to be considered law enforcement digital forensic science organisations when outlining their capability to clients. In addition, a ‘Service Level Allocator’ decision model is offered to allow clients to determine what Service Level is appropriate for their investigation.

Latent print quality in blind proficiency testing: Using quality metrics to examine laboratory performance

Calls for blind proficiency testing in forensic science disciplines intensified following the 2009 National Academy of Sciences report and were echoed in the 2016 report by the President’s Council of Advisors on Science and Technology. Both practitioners and scholars have noted that “open” proficiency tests, in which analysts know they are being tested, allow for test-taking behavior that is not representative of behavior in routine casework. This study reports the outcomes of one laboratory’s blind quality control (BQC) program. Specifically, we describe results from approximately 2.5 years of blind cases in the latent print section (N = 376 latent prints submitted as part of 144 cases). We also used a widely available quality metrics software (LQMetrics) to explore relationships between objective print quality and case outcomes. Results revealed that nearly all BQC prints (92.0%) were of sufficient quality to enter into AFIS. When prints had a source present in AFIS, 41.7% of print searches resulted in a candidate list containing the true source. Examiners committed no false positive errors but other types of errors were more common. Average print quality was in the midpoint of the range (53.4 on a 0-to-100 scale), though prints were evenly distributed across the Good, Bad, and Ugly categories. Quality metrics were significantly associated with sufficiency determinations, examiner conclusions, and examiner accuracy. Implications for blind testing and the use of quality metrics in routine casework as well as proficiency testing are discussed.