Daubert Challenges to Forensic Evidence : Ballistics Next on the Firing Line (original) (raw)

Preventing miscarriages of justice: A review of forensic firearm identification

Science & Justice, 2015

The role of a firearm examiner is wide ranging, involving tasks that require scientific understanding in aspects of 19 chemistry, physics and biology. This article aims to provide a critical review of the key scientific principles and 20 practices specifically involved with forensic firearm identification and to discuss how misidentifications have re-21 sulted in cases of injustice. Implementation of quality assured examination practice, demonstration of individual 22 examiner competence and more objective methods of reporting are being adopted by firearm examiners and lab-23 oratories to address some of the criticisms relating to subjectivity and standardisation inherent within the disci-24 pline. The impact of these changes is outlined and further recommendations are made for both examiners and 25 legal professionals to minimise the potential for future injustices involving firearms evidence. Latest research 26 in the field is cited, continuing to support the theory and use of firearm identification as admissible evidence 27 in court.

Statistical inference and forensic evidence: Evaluating a bullet lead match

Law and Human Behavior, 2007

This experiment tested the ability of undergraduate mock jurors (N = 295) to draw 47 appropriate conclusions from statistical data on the diagnostic value of forensic evidence. Jurors 48 read a summary of a homicide trial in which the key evidence was a bullet lead "match" that 49 was either highly diagnostic, non-diagnostic, or of unknown diagnostic value. There was also 50 a control condition in which the forensic "match" was not presented. The results indicate that 51 jurors as a group used the statistics appropriately to distinguish diagnostic from non-diagnostic 52 forensic evidence, giving considerable weight to the former and little or no weight to the latter.

Forensic Science Evidence in Question

Expert Evidence and Scientific Proof in Criminal Trials, 2017

How should forensic scientists and other expert witnesses present their evidence in court? What kinds and quality of data can experts properly draw on in formulating their conclusions? In an important recent decision in R. v T 1 the Court of Appeal revisited these perennial questions, with the complicating twist that the evidence in question incorporated quantified probabilities, not all of which were based on statistical data. Recalling the sceptical tenor of previous judgments addressing the role of probability in the evaluation of scientific evidence, 2 the Court of Appeal in R. v T condemned the expert's methodology and served notice that it should not be repeated in future, a ruling which rapidly reverberated around the forensic science community causing consternation, and even dismay, amongst many seasoned practitioners. 3 At such moments of perceived crisis it is essential to retain a sense of perspective. There is, in fact, much to welcome in the Court of Appeal's judgment in R. v T, starting with the court's commendable determination to subject the quality of expert evidence adduced in criminal litigation to searching scrutiny. English courts have not consistently risen to this challenge, sometimes accepting rather too easily the validity of questionable scientific techniques. 4 However, the Court of Appeal's reasoning in R. v T is not always easy to follow, and there are certain passages in the judgment which, taken out of context, might even appear to confirm forensic scientists' worst fears. This article offers a constructive reading of R. v T,

Accuracy of comparison decisions by forensic firearms examiners

Journal of Forensic Sciences, 2022

This black box study assessed the performance of forensic firearms examiners in the United States. It involved three different types of firearms and 173 volunteers who performed a total of 8640 comparisons of both bullets and cartridge cases. The overall false-positive error rate was estimated as 0.656% and 0.933% for bullets and cartridge cases, respectively, while the rate of false negatives was estimated as 2.87% and 1.87% for bullets and cartridge cases, respectively. The majority of errors were made by a limited number of examiners. Because chi-square tests of independence strongly suggest that error probabilities are not the same for each examiner, these are maximum-likelihood estimates based on the beta-binomial probability model and do not depend on an assumption of equal examiner-specific error rates. Corresponding 95% confidence intervals are (0.305%, 1.42%) and (0.548%, 1.57%) for false positives for bullets and cartridge cases, respectively, and (1.89%, 4.26%) and (1.16%, 2.99%) for false negatives for bullets and cartridge cases, respectively. The results of this study are consistent with prior studies, despite its comprehensive design and challenging specimens.

Traceability for ballistics signature measurements in forensic science

Measurement, 2009

The National Institute of Standards and Technology (NIST) in collaboration with the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) has developed the Standard Reference Material (SRM) 2460 Bullets and 2461 Casings. NIST has also developed a 2D and 3D Topography Measurement and Correlation System for ballistics signature measurements. This system includes stylus instruments and a confocal microscope for 2D and 3D topography measurements, and a 2D and 3D topography correlation program developed by NIST. NIST and ATF are proposing to establish a National Ballistics Measurement Traceability and Quality System using these materials. In this paper, basic concepts and specific requirements for establishing ballistics measurement traceability are introduced; three key issues are discussed that include: (1) establishing a reference standard; (2) establishing an unbroken chain of calibrations; and (3) evaluating measurement uncertainty for both the geometrical topography measurements and the optical image correlations of the ballistics signatures.

Forensic science – A true science

Australian Journal of Forensic Sciences, 2011

While the US jurisprudence of the 1993 Daubert hearing requires judges to question not only the methodology behind, but also the principles governing, a body of knowledge to qualify it as scientific, can forensic science, based on Locard's and Kirk's Principles, pretend to this higher status in the courtroom? Moving away from the disputable American legal debate, this historical and philosophical study will screen the relevance of the different logical epistemologies to recognize the scientific status of forensic science. As a consequence, the authors are supporting a call for its recognition as a science of its own, defined as the science of identifying and associating traces for investigative and security purposes, based on its fundamental principles and the case assessment and interpretation process that follows with its specific and relevant mode of inference.