Strengthening Forensic Science Research Articles

Error rate and similarity determination of latent fingerprint chemistry via 1D GC and GC × GC–MS

In response to the National Academy of Science’s report on Strengthening Forensic Science, many researchers have investigated ways of improving and supplementing pattern-based visual methods for latent fingerprint (LF) analysis. Gas chromatography (GC) has been used to study the initial and aged chemistry of latent fingerprints, along with attempting to statistically asses same source association with donor characteristics. Since LFs are composed of a complex mixture of oil, sweat, and other components, sections within the chromatographic profile that have poor resolution could benefit from better separation of components, thus yielding more associations to the correct source. This study investigates the potential of increased source association using comprehensive two-dimensional (GC × GC) and one-dimensional (1D) gas chromatography-mass spectrometry (GC–MS). Three LFs from a sample of thirteen volunteers were collected, derivatized with boron trifluoride–methanol (BF3-MeOH), and analyzed via 1D GC and GC × GC–MS. The statistical strength of source association was performed by evaluating the log likelihood ratios (LLRs) obtained from the intra- and inter-personal pairwise Pearson correlation comparisons (PCCs) and using the normal and kernel density comparison R functions. The 1D GC method provided stronger same-source association due to high intra-personal PCC values; however, lower inter-personal PCCs were acquired from GC × GC. Higher area under the curves (AUCs) and LLR calibration were computed for the 1D GC PCCs. Conversely, poor statistical calibration and discriminating power were obtained for both 1D GC and GC × GC methods when assessing the LLRs despite having high AUCs.

Chemometrics in forensic science

Chemometrics in forensic science

Core Competencies in Forensic Anthropology: A Framework for Education, Training, and Practice

Forensic practice, research, and expert testimony has been scrutinized increasingly by the medicolegal system over the last several decades, requiring attention to rigor and triggering reform in the forensic sciences. One hindrance to the forensic science enterprise noted in the National Academy of Sciences report Strengthening Forensic Science in the United States: A Path Forward is fragmentation in education and training among the forensic sciences. It is crucial that practitioners receive appropriate training in their field of expertise and that education programs demonstrate the effectiveness of curricula in producing competent practitioners. This article examines a model for delineating core competencies in forensic anthropology and translating these competencies into measurable activities that characterize the knowledge, skills, and behaviors required of forensic anthropologists. We propose the model used in medical education: core competencies and Entrustable Professional Activities (EPAs). We suggest EPAs that encapsulate the core competencies and allow practitioners to demonstrate that they can be trusted to perform units of professional practice unsupervised. This model emphasizes the abilities to be acquired by trainees, providing education and training programs with a set of guidelines for designing curricula and assessing learners. It also informs certification testing and credentialing in forensic anthropology. In the era of greater accountability, a competency-based model ensures that all board-certified practitioners are competent in all essential domains. The dynamic model also communicates to the medicolegal community and stakeholders the units of work produced by forensic anthropologists and our role in forensic investigations and casework.

A Template for Enhancing the Impact of the National Academy of Sciences’ Reporting on Forensic Science

Abstract The National Academy of Sciences (NAS), established in 1863, is the United States’ leading science and technology think-tank, with an active commitment to advising government. Over the last 150 years, the NAS has, both independently and in conjunction with the federal government, investigated and reported on various issues of importance, ranging from space exploration and biosecurity, to STEM education and immigration. Due to growing concerns about particular disciplines (and specifically their application in legal proceedings), one issue the NAS has reported on between 1992 and 2009 is forensic science. Specifically, the NAS has published six reports commenting on the status of forensic science evidence in the USA, namely DNA Technology in Forensic Science (1992), The Evaluation of Forensic DNA Evidence (1996), The Polygraph and Lie Detection (2003), Forensic Analysis: Weighing Bullet Lead Evidence (2004), Ballistic Imaging (2008), and Strengthening Forensic Science in the United States: A Path Forward (2009). The response of stakeholders (including from political, legal, and academic spheres) to these reports has varied, ranging from shifts in practice and full acknowledgement, to considerable struggles to effectuate systemic reform. Using the different experiences of two reports – Forensic Analysis: Weighing Bullet Lead Evidence (2004) and Strengthening Forensic Science in the United States: A Path Forward (2009) – as a vehicle, this article suggests how the NAS can strengthen the impact of its forensic science reporting, and how stakeholders can better harness the expertise of the NAS.

Ten Years After the National Academy of Sciences’ Landmark Report on Strengthening Forensic Science in the United States: A Path Forward – Where are We?

We are still struggling with the inability of courts to assess the efficacy of forensic evidence. When a forensic expert testifies about a method that has not been found to be valid and reliable, the expert does not know what he does not know and cannot explain the limits of the evidence. This is unacceptable. Judges and juries must understand the levels of uncertainty that are associated with forensic evidence so that they can determine whether the prosecution has met its burden of proving that the defendant is guilty beyond a reasonable doubt. We still need a national, independent agency to oversee forensic research and practices. This was the most important recommendation of the National Academy of Sciences Committee on Identifying the Needs of the Forensic Science Community. We also need more top scientists engaged in serious research to determine the validity and reliability of forensic methods. And we need these individuals to appear in court to explain the limits of the evidence.

Projekt "Mapowanie odbitek linii papilarnych" (część I) - geneza

Since the publication of the National Research Council Report titled: Strengthening Forensic Science in the United States: A Path Forward for the United States Department of Justice, there has been an international discussion on scientific character of fingerprint examination, and Poland has not been excluded from it. The approaches to fingerprint identification in the United States of America and Poland are completely different. In the first case, the holistic standard is used basing exclusively on the experience and conviction of the expert, and in the other one, numerical standard precisely determining the minimum number of consistent individual characteristics (minutiae) required for identification. Both standards have both advantages and significant drawbacks. A good way out of this situation would be finding a solution combing the holistic and numerical approaches and the project “Mapping of friction skin ridges impressions” implemented by the forensic experts of Fingerprint Examination Department in the Central Forensic Laboratory of the Police makes constitutes contribution to that.

Addressing Fragmentation in the Forensic Document Examination Community: Applying the NAS Report's Call for Standardization to the Current State of the Field

ABSTRACTThe National Research Council of the National Academy of Sciences (NAS) released their report, Strengthening Forensic Science in the United States: A Path Forward in 2009. The NAS Committee...

Statistical Issues in Forensic Science

Forensic science refers to the use of scientific methods in a legal context. Several recent events, especially the release in 2009 of the National Research Council (NRC) report Strengthening Forensic Science in the United States: A Path Forward, have raised concerns about the methods used to analyze forensic evidence and the ways in which forensic evidence is interpreted and reported on in court. The NRC report identified challenges including the lack of resources in many jurisdictions compared with the amount of evidence requiring processing, the lack of standardization across laboratories and practitioners, and questions about the analysis, interpretation and presentation of evidence. With respect to the last, the NRC report raises questions about the underlying scientific foundation for forensic examinations on some evidence types. Statistics has emerged as a key discipline for helping the forensic science community address these challenges. The standard elements of statistical analysis—study design, data collection, data analysis, statistical inference, and summarizing and reporting inferences—are all relevant. This article reviews the role of forensic evidence, the heterogeneity of forensic domains, current practices and their limitations, and the potential contributions of more rigorous statistical methods, especially Bayesian approaches and the likelihood ratio, in the analysis, interpretation, and reporting of forensic evidence.

Proficiency Testing Trends Following the 2009 National Academy of Sciences Report, “Strengthening Forensic Science in the United States: A Path Forward”

ABSTRACTThe 2009 NAS Report made several recommendations, among which was a call for increased accreditation of forensic laboratories and certification of forensic scientists. Proficiency testing, a key quality measure for both accreditation and certification, was also cited in the Report as being mandatory to achieve and maintain these quality indicators. Data from a proficiency test provider was analyzed from the period of 2008–2015 to examine if laboratories were increasing proficiency testing by examining enrollment numbers and the return rate of the completed proficiency tests. Noting a key difference in domestic and international laboratories, additional data from the period of 2004–2015 was analyzed to examine the return rate of proficiency tests against the percentage of reports released to accreditation bodies. The entirety of the data was reviewed to see if the 2009 NAS Report's recommendations were being enacted by looking for an increasing number of accredited laboratories enrolling in profici...

Fingerprint identification: advances since the 2009 National Research Council report.

This paper will discuss the major developments in the area of fingerprint identification that followed the publication of the National Research Council (NRC, of the US National Academies of Sciences) report in 2009 entitled: Strengthening Forensic Science in the United States: A Path Forward. The report portrayed an image of a field of expertise used for decades without the necessary scientific research-based underpinning. The advances since the report and the needs in selected areas of fingerprinting will be detailed. It includes the measurement of the accuracy, reliability, repeatability and reproducibility of the conclusions offered by fingerprint experts. The paper will also pay attention to the development of statistical models allowing assessment of fingerprint comparisons. As a corollary of these developments, the next challenge is to reconcile a traditional practice dominated by deterministic conclusions with the probabilistic logic of any statistical model. There is a call for greater candour and fingerprint experts will need to communicate differently on the strengths and limitations of their findings. Their testimony will have to go beyond the blunt assertion of the uniqueness of fingerprints or the opinion delivered ispe dixit.

Assessing the effect of data pretreatment procedures for principal components analysis of chromatographic data

Following publication of the National Academy of Sciences report “Strengthening Forensic Science in the United States: A Path Forward”, there has been increasing interest in the application of multivariate statistical procedures for the evaluation of forensic evidence. However, prior to statistical analysis, variance from sources other than the sample must be minimized through application of data pretreatment procedures. This is necessary to ensure that subsequent statistical analysis of the data provides meaningful results.The purpose of this work was to evaluate the effect of pretreatment procedures on multivariate statistical analysis of chromatographic data obtained for a reference set of diesel fuels. Diesel was selected due to its chemical complexity and forensic relevance, both for fire debris and environmental forensic applications. Principal components analysis (PCA) was applied to the untreated chromatograms to assess association of replicates and discrimination among the different diesel samples. The chromatograms were then pretreated by sequentially applying the following procedures: background correction, smoothing, retention-time alignment, and normalization. The effect of each procedure on association and discrimination was evaluated based on the association of replicates in the PCA scores plot. For these data, background correction and smoothing offered minimal improvement, whereas alignment and normalization offered the greatest improvement in the association of replicates and discrimination among highly similar samples. Further, prior to pretreatment, the first principal component accounted for only non-sample sources of variance. Following pretreatment, these sources were minimized and the first principal component accounted for significant chemical differences among the diesel samples. These results highlight the need for pretreatment procedures and provide a metric to assess the effect of pretreatment on subsequent multivariate statistical analysis of complex data.

Analyses of Death Investigation Systems and Forensic Pathology: A Brief Historical Account

Since 1928, there have been multiple analyses and reports issued about the status and needs of death investigation systems in the United States. Using references contained in the National Research Council's (NRC) report, “Strengthening Forensic Science in the United States: A Path Forward,” and backtracking references from those documents, previous reports and meeting agendas were obtained and reviewed which relate to formal study or discussion of death investigations systems and forensic pathology dating back to 1928. These include National Research Council Bulletins from 1928 and 1932, the 1954 “Model Postmortem Examinations Act,” a 1968 Forensic Pathology Progress Report, the 1985 Wingspread Symposium, a 2003 Institute of Medicine Death Investigation Workshop, a 2004 National Association of Medical Examiners Report on America's Medicolegal Offices, the 2009 NRC Report on Strengthening Forensic Science, and a 2010 Forensic Death Investigation Summit. These events and reports are briefly reviewed in this article. Over the past 82 years, needs for the death investigation system have been described. Although progress has been made in meeting those needs and improving death investigation systems, progress has been slow and much work remains to be done. Recent formation of the National Commission on Forensic Science and the National Institute of Standards and Technology's Organization of Scientific Areas Committees (OSAC) may provide an impetus for more rapid and significant change.

C.S.I. Bulls#!t: The National Academy of Sciences, Melendedez-Diaz v. Massachusetts, and Future Challenges to Forensic Science and Forensic Evidence,

Good law depends on good science. The February 18, 2009, National Academy of Sciences report, Strengthening Forensic Science in the United States: A Path Forward (“NAS Report”), reveals that, for the most part, forensic science is bad science. The NAS Report also suggests that when confronted with forensic science, most courts make bad law.

C.S.I. Bulls#!T: The National Academy of Sciences, Melendedez-Diaz V. Massachusetts, and Future Challenges to Forensic Science and Forensic Evidence

Good law depends on good science. The February 18, 2009, National Academy of Sciences report, Strengthening Forensic Science in the United States: A Path Forward (“NAS Report”), reveals that, for the most part, forensic science is bad science. The NAS Report also suggests that when confronted with forensic science, most courts make bad law.

National Academy of Sciences "standardization": on what terms?

The frequently cited 2009 National Academy of Sciences Report entitled "Strengthening Forensic Science in the United States: A Path Forward" has become a focal point of forensic science practitioners' discussions and research since its publication. One of its recommendations is "Standardized Terminology and Reporting". Little has been published to date on this topic, although conversations and dialogs on the subject are ongoing. The upshot of this communication is to draw attention to the problem of one term in particular, perimortem, which may be only the proverbial "tip of the iceberg" in the lexicon-related concerns of forensic scientists. Even if it is an isolated issue, it is one that reflects the need for a consensus on term use and definitions by interdisciplinary practitioners who are currently using the term haphazardly, to the confusion of colleagues and potentially finders-of-fact in the courts.

Appraisal of scientific evidence in criminal justice systems: on winds of change and coexisting formats

Interpretation concepts of scientific evidence have always been under discussion among forensic scientists and among all stakeholders of criminal proceedings in general. It seems that this issue has been attracting more attention since the introduction of the case assessment and interpretation (CAI) model in the late nineties and even more since the release of the National Academies of Science report ‘Strengthening Forensic Science in the United States’ in 2009. Following the debates there is, however, a certain danger of overcompensation if the input of stakeholders from e.g. inquisitorial criminal systems is under-represented. Without doubt, a likelihood ratio-based approach can be a powerful tool assisting in logically complex case assessments and judicial considerations of evidence. However, the application of this approach should be an option rather than an international standard as it concerns the concept of the stakeholder’s roles more profoundly in some countries than in others and may possibly take some countries by surprise. In the following article, this is discussed and some proposals are put forward which appear suitable to strengthen the evaluation of forensic results by the principle of methodological pluralism rather than by an exclusive and compulsory commitment to only one approach.

A Canadian perspective on forensic science versus pseudoscience

This presentation will provide my personal observations regarding forensic science versus pseudoscience in the Canadian legal system. I am neither a lawyer nor a judge; rather, I am a forensic scientist with over 25 years of experience in the Canadian system. My presentation focuses on relevant criteria for expert evidence considered in Canadian courts. The key ruling in R. v. Mohan (1994) provides the start of the discussion with subsequent court rulings adding various elements. In Canada, we have had several judicial inquiries, such as the Kaufmann Commission, that can serve to guide experts. Select aspects of the 2009 NAS report “Strengthening Forensic Science in the United States: A Path Forward” will also be referenced. There are some common “criteria” often used by courts in different jurisdictions to assess expert evidence, including forensic acoustics. In other words, some basic expectations for all forms of expert evidence can be identified. I will attempt to show how select “sciences” have tried to fulfill those expectations. This will involve some commentary on issues of individual examiner competency, oversight at a system level (e.g., accreditation), and the need for proper and adequate method validation.

Addressing the National Academy of Sciences’ Challenge: A Method for Statistical Pattern Comparison of Striated Tool Marks

In February 2009, the National Academy of Sciences published a report entitled "Strengthening Forensic Science in the United States: A Path Forward." The report notes research studies must be performed to "…understand the reliability and repeatability…" of comparison methods commonly used in forensic science. Numerical classification methods have the ability to assign objective quantitative measures to these words. In this study, reproducible sets of ideal striation patterns were made with nine slotted screwdrivers, encoded into high-dimensional feature vectors, and subjected to multiple statistical pattern recognition methods. The specific methods employed were chosen because of their long peer-reviewed track records, widespread successful use for both industry and academic applications, rely on few assumptions on the data's underlying distribution, can be accompanied by standard confidence levels, and are falsifiable. For PLS-DA, correct classification rates of 97% or higher were achieved by retaining only eight dimensions (8D) of data. PCA-SVM required even fewer dimensions, 4D, for the same level of performance. Finally, for the first time in forensic science, it is shown how to use conformal prediction theory to compute identifications of striation patterns at a given level of confidence.

Forensic science, an enabler or dis-enabler for criminal investigation?

It would be hard to imagine any significant criminal investigation today to which some aspect of forensic science did not contribute. But does this mean forensic science is used effectively in the broader justice system? Media headlines abound with criticisms of forensic work delaying the justice process. DNA is often held up as the gold standard to which other aspects of forensic science should aspire. The recently released US National Academies Report, Strengthening forensic science in the US: a path forward1, raised significant concerns about the knowledge baseand practice of forensic science, at least as it is conducted in the US. So where does the truth lie? Is forensic science robust and reliable? Is forensic science effective and/or efficient in support of criminal investigation? This article explores these issues and offers some thoughts for the forensic profession but also challenges the justice system community to develop a more collegiate approach to the use of forensic science to improve its efficiency in supporting the criminal justice system.

10 Best of Good Laboratory Practices for Forensic Facilities: A Key to Satisfying Daubert's Gatekeeper and Rule 702

Abstract The admissibility of forensic evidence and related testimony into federal court falls under the expert witness rules of the Federal Rules of Evidence, specifically Rule 702. A 1993 ruling in Daubert v. Merrell Dow Pharmaceuticals significantly affected this rule. This decision was later used by the Supreme Court to help interpret Rule 702 (General Electric Co. v. Joiner). The rule gives the “trier of fact”—that is, the judge—broad authority to decide the admissibility of forensic testimony and evidence. This has been referred to as a “gatekeeper” role. In 2009, the National Academy of Sciences issued a report on the state of forensic science in the nation, Strengthening Forensic Science in the United States: A Path Forward, commissioned by Congress. The report recommended that an initial focus be “establishing and enforcing best practices for forensic science professionals and laboratories” (National Academy of Sciences 2009, p. 81). It is not surprising that all of the 10 best laboratory practices discussed in this paper are addressed in the widely accepted international standard for analysis laboratories and facilities, ISO-17025: General Requirements for the Competence of Testing and Calibration Laboratories. All good laboratories will regard these 10 best practices as well entrenched in their daily laboratory routines. However, an occasional revisit, particularly for non-accredited facilities, has value in the light of the National Academies’ report. Adopting these practices will provide justification that test results are valid. They can provide the key for the gatekeeper to allow test results and testimony into proceedings. Additionally, following these best practices can be a defense as to why a forensic scientist did or did not perform certain testing, thus overcoming TV-Land's “CSI effect” for jurors.