Forensic Science Evidence Research Articles

Science, Technology, or the Examiner Experience: What Influences Jurors' Judgments About Forensic Science Testimony?

The impact of forensic science evidence on jurors’ judgments is critically important to the criminal justice system. The assignment of low or high weight to such testimony can be the difference between acquittal or conviction. Many of the traditional forensic sciences (e.g., fingerprints and bitemarks) draw their strength largely from the subjective judgments of examiners who testify about whether evidentiary prints or other markings are consistent with (or “match”) known markings from a person or object. In an online experiment (Experiment 1) and a realistic jury simulation using actual jurors or jury-eligible adults (Experiment 2), this paper investigates three factors that might affect how jurors think about and use forensic science evidence. These factors are (a) whether the forensic science method had been scientifically tested, (b) the forensic scientist’s background and experience, and (c) how sophisticated the forensic science technology is. The results show a strong and consistent effect for examiner background and experience on evidence strength judgments, no effect for forensic technology sophistication, and a limited and inconsistent effect for scientific testing (present in the online experiments, absent in the realistic jury simulation). These findings raise concerns about potential undue influence of examiner background and experience on jurors’ judgments, and lack of clear influence of scientific testing. The implications of our findings for criminal justice practices and policies are considered.

Cognitive Bias and Blindness: A Global Survey of Forensic Science Examiners

Exposure to irrelevant contextual information prompts confirmation-biased judgments of forensic science evidence ( Kassin, Dror, & Kukucka, 2013 ). Nevertheless, some forensic examiners appear to believe that blind testing is unnecessary. To assess forensic examiners’ beliefs about the scope and nature of cognitive bias, we surveyed 403 experienced examiners from 21 countries. Overall, examiners regarded their judgments as nearly infallible and showed only a limited understanding and appreciation of cognitive bias. Most examiners believed they are immune to bias or can reduce bias through mere willpower, and fewer than half supported blind testing. Furthermore, many examiners showed a bias blind spot ( Pronin, Lin, & Ross, 2002 ), acknowledging bias in other domains but not their own, and in other examiners but not themselves. These findings underscore the necessity of procedural reforms that blind forensic examiners to potentially biasing information, as is commonplace in other branches of science.

Neglected Physical Evidence during Crime Scene Investigation

Forensic Science & Addiction Research Neglected Physical Evidence during Crime Scene Investigation Nataraja Moorthy T* Faculty of Health and Life Sciences, Management and Science University, Malaysia *Corresponding author: Nataraja Moorthy T, Faculty of Health and Life Sciences, Management and Science University, Shah Alam, Malaysia Submission: August 21, 2017; Published: October 03, 2017 DOI: 10.31031/FSAR.2017.01.000507 ISSN: 2578-0042 Volume1 Issue2

Taking forensic mental health assessment "out of the lab" and into "the real world": Introduction to the special issue on the field utility of forensic assessment instruments and procedures.

The last several decades have seen a major upswing in the development and use of psychological assessment instruments in forensic and correctional settings. At the same time, admissibility standards increasingly have stressed the importance of the reliability and validity of evidence in legal proceedings. Recent research has, however, raised serious concerns about (a) the reliability of forensic science evidence in general, (b) the replicability of psychological research findings in general and in field settings especially, and (c) the interrater reliability and predictive validity of forensic psychological assessment evidence in particular. In this introduction to the special issue of Psychological Assessment on the field utility of forensic assessment instruments and procedures, we provide an overview of key issues bearing on field studies, focusing on why such research is critically important to improving the quality of the practice of forensic mental health assessments. We also identify various methodological issues and constraints relevant to conducting research outside of controlled settings. We conclude with recommendations for how future field research can improve upon the current state of the discipline in forensic mental health assessment. (PsycINFO Database Record

Courtroom forensic evidence often lacks scientific validity, report finds

Improvements will require coordination among the US judicial, law enforcement, and scientific communities.

Moving Toward New Requirements for the Admissibility of Evidence

The admissibility of forensic science evidence requires the side proffering the evidence to demonstrate that Daubert or the Federal Rules of Evidence, Rule 702 were followed. Thus, testifying exper...

Opening the Scientific Expert’s Black Box

The work of forensic scientists, by providing specialist assistance beyond the normal experience or knowledge of the factfinders, can be elusive to the law’s traditional probative safeguards. These safeguards, in any case, only apply to the small proportion of such evidence actually tested in court. The specialist nature of the scientific work and the knowledge and understanding needed by users with a non-scientific background makes trust in forensic science problematic if conceptualised in binary terms. A systematic review of the development of the quality controls for the production and use of expert scientific evidence demonstrates that critical trust, as an organising principle, does offer a continuum (ranging from scepticism to acceptance) for assessing the reliability and use of forensic science evidence. Despite progressive reform in forensic science, significant risks remain. These risks are both (i) scientific, including the fragmentation of scientific interpretation and the assurance that all providers and/or processes can meet the necessary standards, and (ii) professional, ranging from the timely provision of information to the ability of counsel to critically test the evidence in a manner intelligible to the factfinders.

Intuitive Error Rate Estimates for the Forensic Sciences

There is a risk of error associated with all forensic science conclusions. However, no proper studies have been conducted in any of the forensic sciences to estimate the rate at which forensic science conclusions are wrong. As a result, jurors and other consumers of forensic science information are left to speculate about what those error rates might be. The present paper provides data from an online study (n = 210) about what jury-eligible people (“jurors”) think the false positive error rates are for five types of forensic science evidence (DNA, fingerprints, bite marks, microscopic hair, and handwriting). Jurors’ median estimates range from a high of 1 in 100,000 (handwriting) to a low of 1 in 1,000,000,000 (DNA). The significance of these estimated false positive error rates is discussed.

Posterior distributions for likelihood ratios in forensic science

Evaluation of evidence in forensic science is discussed using posterior distributions for likelihood ratios. Instead of eliminating the uncertainty by integrating (Bayes factor) or by conditioning on parameter values, uncertainty in the likelihood ratio is retained by parameter uncertainty derived from posterior distributions. A posterior distribution for a likelihood ratio can be summarised by the median and credible intervals. Using the posterior mean of the distribution is not recommended. An analysis of forensic data for body height estimation is undertaken. The posterior likelihood approach has been criticised both theoretically and with respect to applicability. This paper addresses the latter and illustrates an interesting application area.

A little ignorance is a dangerous thing: engaging with exogenous knowledge not adduced by the parties

ABSTRACTUsing a recent trial and appeal in Canada as an example, this essay reviews our conventional reticence to allowing judges to draw the attention of counsel to issues that might influence the assessment of forensic science evidence in criminal proceedings. We question the institutional commitment to judicial non-intervention and suggest that on many occasions judicial passivity or quiescence (rather than impartiality) threatens the fundamental goals of fairness and factual rectitude. The essay explores the scope and rationale for judicial engagement with exogenous knowledge within the confines of adversarialism.

Presenting Quantitative and Qualitative Information on Forensic Science Evidence in the Courtroom

An abundant scientific and legal literature, as well as several reports from the U.S. National Academy of Sciences, demands that forensic findings be supported by data and that conclusions be logic...

Forensic Science Identification Evidence

For decades, courtrooms around the world have admitted evidence from forensic science analysts, such as fingerprint, tool-mark and bite-mark examiners, in order to solve crimes. Scientific progress, however, has led to significant criticism of the ability of such disciplines to engage in individualization i.e., “match” suspects exclusively to evidence. Despite this, American courts largely reject legal challenges based on arguments that identification evidence provided by these forensic science disciplines is unreliable. In so holding, these courts affirm precedent that it is the adversarial system’s function to weed out frailties in forensic evidence, and find that criticism of the forensic sciences lacks sui generis qualities. This article provides an independent critique of relevant American case law, from which three themes emerge. These themes are (1) the law’s misuse of science; (2) law’s scepticism towards change; and (3) law’s narrow construction of rationality, which generates reductionist concepts, and divorces science from its social context. As such, this article shows how the American judiciary’s approach to this global issue provides a contemporary illustration of key institutional tensions between science and law, and offers some recommendations for reforms that aim to facilitate the legal process to utilize the most reliable forensic science evidence possible.

Legal versus non-legal approaches to forensic science evidence

In their attempts to determine the admissibility and probative value of forensic science and medicine evidence, common law courts have tended to focus on considerations such as: the formal qualifications and training of the analyst, the analyst’s experience doing the same or similar things, the existence of a field, whether the evidence might assist the jury, apparent partisanship and plausibility, the overall strength of the case and even the perceived need to accommodate technological innovation. This article reviews conventional English approaches to the admission and evaluation of expert evidence. It aims to contrast legal approaches to forensic science evidence with the kinds of criteria being promoted by a range of peak scientific organisations. This comparative exercise suggests that admissibility jurisprudence and legal practice might be misguided, particularly in their attempts to regulate the comparison or pattern matching disciplines. The article will suggest that courts have privileged the wrong kinds of heuristics in their attempts to engage with scientific and technical forms of knowledge. More disturbingly, it questions whether conventional admissibility standards, even in conjunction with trial safeguards, provide jurors and judges with the kinds of information required to rationally assess much of the incriminating expert opinion evidence routinely presented in criminal proceedings.

Paradigms of forensic science and legal process: a critical diagnosis.

This article reconsiders the relationship between criminal adjudication and forensic expertise in the light of 'new paradigms' of forensic practice and recent law reform. It briefly summarizes conventional wisdom on the typical shortcomings of forensic science and other expert evidence, as a springboard for a more searching critical diagnosis of longstanding maladies. The fundamentally jurisdictional nature of law is emphasized, and some implications for expert testimony noted. English law's traditionally adversarial model of criminal procedure is then reassessed, taking account of a proper understanding of its normative structure and modern development, and drawing on comparative legal research and theorizing to obtain a more rounded second opinion. In conclusion, some avenues for intelligent prescription are canvassed, highlighting the importance of promoting and facilitating effective communication between experts, lawyers and courts, and prioritizing modest practical remedies over radical surgery.

The legal framework for more robust forensic science evidence.

The legal framework for more robust forensic science evidence.

Attorney beliefs concerning scientific evidence and expert witness credibility

Expert witnesses play a pivotal role in offering a variety of scientific evidence at trial. Although judges are the ultimate gatekeepers of what constitutes valid scientific evidence, attorneys play an important part in determining what evidence is presented to the court. Employing experimental and descriptive analyses, the present study sought to address gaps in the attorney/expert witness literature by addressing three questions: One) To what extent do attorneys prefer forensic or social scientific evidence and experts?, Two) How knowledgeable are attorneys concerning empirically-supported indicators of expert credibility?, Three) What do attorneys believe concerning the frequency and nature of expert errors in their own trials relative to others? Results showed that attorneys prefer forensic science evidence and experts compared to social/psychological counterparts. Moreover, attorneys displayed considerable knowledge of factors that will impact perceived expert credibility. In particular, attorneys value perceived expert trustworthiness, communication skills, content of testimony/reports, perceived expert knowledge, and years and type of expert experience. Finally, attorneys displayed a consistent and strong self-serving bias pattern, such that they believe expert errors occur more much frequently in other attorneys' cases compared to their own. Implications are discussed with respect to vetting expert witnesses, scientific evidence/errors and wrongful conviction, and training for attorneys.

Forensic scientific evidence: problems and pitfalls in India

Forensic scientific evidence: problems and pitfalls in India

Spherical photography and virtual tours for presenting crime scenes and forensic evidence in new zealand courtrooms.

The delivery of forensic science evidence in a clear and understandable manner is an important aspect of a forensic scientist's role during expert witness delivery in a courtroom trial. This article describes an Integrated Evidence Platform (IEP) system based on spherical photography which allows the audience to view the crime scene via a virtual tour and view the forensic scientist's evidence and results in context. Equipment and software programmes used in the creation of the IEP include a Nikon DSLR camera, a Seitz Roundshot VR Drive, PTGui Pro, and Tourweaver Professional Edition. The IEP enables a clear visualization of the crime scene, with embedded information such as photographs of items of interest, complex forensic evidence, the results of laboratory analyses, and scientific opinion evidence presented in context. The IEP has resulted in significant improvements to the pretrial disclosure of forensic results, enhanced the delivery of evidence in court, and improved the jury's understanding of the spatial relationship between results.

An English Daubert? Law, Forensic Science and Epistemic Deference

A test for the admissibility of expert evidence, partly derived from Daubert, has recently been introduced into English criminal law by the unusual mechanism of a Practice Direction. This article compares the Daubert trilogy and the English Practice Direction as responses to the problem of epistemic deference by juries to experts. Juries are often justified in deferring to experts as to the relevance of the underlying evidence examined by the expert, including what inferences can be drawn from it. There is a concern, however, that juries may also defer to experts’ claims about the weight of their own evidence: how strongly or confidently those inferences can be stated. Overly deferential jurors may place excessive weight on forensic science evidence that rests on shaky foundations. The new English admissibility regime (drawing on recommendations by the Law Commission) appears better tailored than Daubert to address this issue about the strength of inferences presented by expert witnesses. As a result, however, it places considerable demands in judges, advocates and expert witnesses, and how successful it will be in practice remains to be seen. Introduction Until very recently, England and Wales had nothing like a Daubert test for admissibility of expert evidence. Civil judges, who normally decide cases without juries, play an active ‘gatekeeping’ role but it is focused explicitly on casemanagement and cost reduction – which are arguably the real aims of Daubert (Jacob 2009; Faigman 2013). In the criminal courts there have been few reported decisions to exclude any kind of expert evidence except that of psychiatrists or psychologists. Effective 7 October 2014, however, an admissibility test recognizably derived from Daubert has been introduced into the criminal courts by the somewhat unusual mechanism (for such a significant change) of a Practice Direction issued by the Lord Chief Justice (Thomas 2014a). As Lord Thomas has acknowledged, the Practice Direction amounts to “a novel way of implementing an excellent report” by the Law Commission, an advisory body whose proposals for a new statutory admissibility test were rejected by the government (Thomas 2014b, 6). The Commission’s report, in turn, was a response to the recommendation of a parliamentary committee that an admissibility test based on Daubert was needed to reduce the risks posed by unreliable forensic science or medical evidence (House of Commons 2005). Those risks had been highlighted by a series of notorious miscarriages of justice, including major cases of terrorism in the

Lay understanding of forensic statistics: Evaluation of random match probabilities, likelihood ratios, and verbal equivalents.

Forensic scientists have come under increasing pressure to quantify the strength of their evidence, but it is not clear which of several possible formats for presenting quantitative conclusions will be easiest for lay people, such as jurors, to understand. This experiment examined the way that people recruited from Amazon's Mechanical Turk (n = 541) responded to 2 types of forensic evidence--a DNA comparison and a shoeprint comparison--when an expert explained the strength of this evidence 3 different ways: using random match probabilities (RMPs), likelihood ratios (LRs), or verbal equivalents of likelihood ratios (VEs). We found that verdicts were sensitive to the strength of DNA evidence regardless of how the expert explained it, but verdicts were sensitive to the strength of shoeprint evidence only when the expert used RMPs. The weight given to DNA evidence was consistent with the predictions of a Bayesian network model that incorporated the perceived risk of a false match from 3 causes (coincidence, a laboratory error, and a frame-up), but shoeprint evidence was undervalued relative to the same Bayesian model. Fallacious interpretations of the expert's testimony (consistent with the source probability error and the defense attorney's fallacy) were common and were associated with the weight given to the evidence and verdicts. The findings indicate that perceptions of forensic science evidence are shaped by prior beliefs and expectations as well as expert testimony and consequently that the best way to characterize and explain forensic evidence may vary across forensic disciplines.