Forensic Gait Analysis and Recognition: Standards of Evidence Admissibility

Gait is one biological characteristic which has attracted strong research interest due to its potential use in human identification. Although almost two decades have passed since a forensic gait expert has testified to the identity of a perpetrator in court, the methods remain insufficiently robust, considering the recent paradigm shift witnessed in the forensic science community regarding quality of evidence. In contrast, technological advancements have taken the lead, and research into automated gait recognition has greatly surpassed forensic gait analysis in terms of the size of acquired datasets and demographic variability of participants, tested variables, and statistical evaluation of results. Despite these advantages, gait recognition presents with different problems which are yet to be resolved. Therefore, courts should treat gait evidence with caution, as they should any other form of evidence originating from disciplines without fully established codes of practice, error rates, and demonstrable applications in forensic scenarios.     

Communicating forensic scientific expertise: An analysis of expert reports and corresponding testimony in Tasmanian courts

Forensic criminology examines the use of forensic science in society. Justice can be hampered, for example, if the communication of forensic scientific findings is unclear or misleading, even if unintentionally. Although various recommendations guide the communication of forensic science, it is unclear whether they are reflected in practice. This study explored the communication of forensic biology in 10 cases of major crimes against the person heard in the Tasmanian Supreme Court, where the standard practice is to issue brief summary reports in the first instance. The content of expert reports and corresponding testimony was analysed to determine its adherence to recommendations outlined in standards, practice notes, and research. While reports were found to be very brief, testimony elaborated on all major elements. Mostly elicited by the prosecution, some elements were volunteered by expert witnesses, or raised by defence. Overall, expert evidence in courts—but not reports (due to the use of brief summary reports)—largely adhered to recommendations. Further research is needed to determine the prevalence and effectiveness of alternative approaches to communication that were identified in certain cases.     

The repeatability and reproducibility of the Sheffield Features of Gait Tool

Gait, the pattern or style in which locomotion is undertaken, has kinematic characteristics that may occur in varying proportions of a population and therefore have discriminatory potential. Forensic gait analysis is the analysis, comparison and evaluation of features of gait to assist the investigation of crime. While there have been recent developments in automated gait recognition systems, gait analysis presented in criminal court to assist in identification currently relies on observational analysis by expert witnesses. Observational gait analysis has been the focus of considerable research, and it has been shown that the adoption of a systematic approach to both the observation and recording of features of gait improves the reliability of the analysis. The Sheffield Features of Gait Tool was developed by forensic gait analysis practitioners based on their casework and trial experience, and consists of more than a hundred features of gait and variances. This paper reports the findings of a study undertaken to assess the repeatability and reproducibility of the Sheffield Features of Gait Tool.Fourteen participants, with experience in observational gait analysis, viewed footage of computer generated avatars walking, and completed the features of gait tool on multiple occasions. The repeatability scores varied between participants from a highest score of 42.59 out of a maximum possible score of 45 (94.65%), to a lowest score of 30.76 (68.35%), with a mean score of 35.79 (79.54%) and a standard deviation of 3.59 (7.98%). The reproducibility scores for the assessment of each avatar varied from a highest score of 137.73 out of the best possible score of 180 (76.52%), to a lowest score of 127.21 (70.67%), with a mean score of 132.21 (73.45) and a standard deviation of 3.82 (2.12%). The results demonstrated that the use of the Sheffield Features of Gait Tool by experienced analysists resulted in what could be considered to be good levels of both repeatability and reproducibility. Some variation was shown to occur both between the results produced by different analysts, and between those produced from the analysis of different avatars. An understanding of the probative value of gait analysis evidence is an important facet of its submission as evidence, and the design and testing of standardized methods of analysis and comparison are an essential element of developing that understanding. This study is the first to test a purpose designed features of gait tool for use in forensic gait analysis.     

Peer‐Reviewed Forensic Consultation in Practice: Multidisciplinary Oversight in Common Expertise

The fallibility of forensic science consultation is an ongoing and major justice concern. Prospective peer‐reviewed forensic consultation has over 10 years of application in American criminal and civil courts, adapting from the traditional oversight of teaching hospitals, rules of evidence and discovery, conventions of testimony of expert witnesses, and attorneys' overall trial strategy. In systematizing heightened oversight, this process ensures greater accountability in forensic science consultation. The integration of peer reviewers' complementary expertise and experience enhances the sophistication and overall quality of assessment. Forensic examination frequently involves the interface of different specialties. Multidisciplinary peer review augments expert proficiency with that of professional peers having different vantage points from relevant scientific disciplines. This approach ensures greater sophistication of a case inquiry, built‐in accountability, and streamlined processes when multiple experts are necessitated. Here, the authors present examples of several cases and the primary and secondary benefits of this collaborative, rigorous, cross‐disciplinary exercise.     

The Griffiths Question Map: A Forensic Tool For Expert Witnesses’ Assessments of Witnesses and Victims’ Statements

Expert witnesses are sometimes asked to assess the reliability of young witnesses and victims’ statements because of their high susceptibility to memory biases. This technical note aims to highlight the relevance of the Griffiths Question Map (GQM) as a professional forensic tool to improve expert witnesses’ assessments of young witnesses and victims’ testimonies. To do so, this innovative question type assessment grid was used to proceed to an in‐depth analysis of the interview of an alleged 13‐year‐old victim of a sexual assault and two rapes. Overall, the GQM stressed how the interview was mainly conducted in an inappropriate manner. The results are examined with regard to scientific knowledge on young witnesses and victims’ memory. Finally, it is argued that expert witnesses in inquisitorial systems might use the GQM while encountering difficulties to fulfill the legal standards for expert evidence in adversarial systems because of the lack of studies regarding its reliability.     

The accuracy and validity of the Sheffield Features of Gait Tool

Gait is now widely used in the UK as a contributor to identification, and increasing interest is being shown in its use in both Europe and the US. One of the long standing criticisms of the use of gait as evidence has been the lack of a validated standard methodology. With the publication of the ‘Code of practice for forensic gait analysis’, and the adoption of the code as part of the ‘Codes of Practice and Conduct for forensic science providers and practitioners in the Criminal Justice System’ by the Forensic Science Regulator, forensic gait analysts are now required to provide evidence of the testing of the methods used. The Sheffield Features of Gait Tool is specifically designed to assist observational gait analysis in the forensic context, and was developed by forensic gait analysis practitioners based on their casework and trial experience. Birch et al 2019 reported the findings of a study undertaken to assess the repeatability and reproducibility of the tool. This paper reports the findings of a study undertaken to assess the accuracy with which analysts identified features of gait when using the tool.Fourteen participants, with experience in observational gait analysis, viewed footage of computer generated avatars walking, and completed the features of gait tool on multiple occasions. The results showed a mean accuracy score of 134.92 out of a possible 180 (74.96%), a standard deviation of 9.49 (5.27%) and a coefficient of variation of 7.03%, demonstrating a good degree of consistency between the scores (Cronbach’s alpha <0.90; ANOVA p-value <0.05).The findings of this study, coupled with those of the Birch et al 2019 study which showed there to be good levels of both repeatability and reproducibility of observations of features of gait made by the participants, suggest that the Sheffield Features of Gait Tool is a valid and fit for purpose method of observing and recording features of gait in the forensic context. The use of the tool provides the basis of a standardised methodology for observational gait analysis in the forensic context.     

Posttraumatic stress disorder in tort actions: forensic minefield

The authors discuss posttraumatic stress disorder (PTSD) as a basis for personal injury litigation. Three case examples raise issues related to: (1) the controversy surrounding expansion of tort liability, (2) the courtroom use of psychiatric nomenclature as represented in the DSM (e.g., PTSD), and (3) ethical concerns regarding psychiatric expert witnesses. Psychiatrists became easy targets when problems related to personal injury "stress" cases developed. A careful analysis, however, demonstrates that the issues are complex and multifaceted. For example, tort liability expansion was primarily instituted to compel a greater provision of liability insurance, not to reward stress claims. The increasing use of psychiatry's DSM in the courtroom has occurred despite explicit precautions against forensic application. Finally, the need for psychiatric expert witnesses has increased because courts have gradually usurped some psychiatric clinical prerogatives and because there has been a trend toward greater consideration of emotional pain and suffering. Although psychiatric expert witnesses have not been beyond reproach, critics have attempted to impeach the entire psychiatric profession for the questionable actions of the minority. The authors provide a detailed analysis of current problems, offer suggestions for improvement, and provide an educational counterpoint to the "hysterical invective" that often greets psychiatric testimony.     

科学证据可采性规则研究

科学证据是运用科学知识和科学方法对证据分析所得的判断意见。因此,科学证据属于意见性证言。为防止不可靠的科学证据对法庭的误导,英美法系国家建立了科学证据可采性规则,包括相关性规则、必要性规则、专家证人资格规则、排除规则、可靠性规则。美国科学证据可靠性规则经历了从Frye规则、Daubert规则到修订后的《联邦证据规则》702条的嬗变。我国对鉴定意见的审查主要限于相关性和合法性的审查。由于缺少对鉴定意见可靠性审查的指导与限制,导致了错误裁决的风险。本文提出确立鉴定意见科学可靠性规则的构想,以利于法官排除错误的鉴定意见,同时有助于法庭科学实验室的管理与制度完善,促使法庭科学实验室更严谨更科学地为法庭提供优质的法庭科学服务。     

Of earprints, fingerprints, scent dogs, cot deaths and cognitive contamination--a brief look at the present state of play in the forensic arena

Over the last decades, the importance of technical and scientific evidence for the criminal justice system has been steadily increasing. Unfortunately, the weight of forensic evidence is not always easy for the trier of fact to assess, as appears from a brief discussion of some recent cases in which the weight of expert evidence was either grossly over- or understated. Also, in recent years, questions surrounding the value of forensic evidence have played a major role in the appeal and revision stages of a number of highly publicized criminal cases in several countries, including the UK and the Netherlands. Some of the present confusion is caused by the different ways in which conclusions are formulated by experts working within the traditional approach to forensic identification, as exemplified by (1) dactyloscopy and (2) the other traditional forensic identification disciplines like handwriting analysis, firearms analysis and fibre analysis, as opposed to those working within the modern scientific approach used in forensic DNA analysis. Though most clearly expressed in the way conclusions are formulated within the diverse fields, these differences essentially reflect the scientific paradigms underlying the various identification disciplines. The types of conclusions typically formulated by practitioners of the traditional identification disciplines are seen to be directly related to the two major principles underpinning traditional identification science, i.e. the uniqueness assumption and the individualization principle. The latter of these is shown to be particularly problematic, especially when carried to its extreme, as embodied in the positivity doctrine, which is almost universally embraced by the dactyloscopy profession and allows categorical identification only. Apart from issues arising out of the interpretation of otherwise valid expert evidence there is growing concern over the validity and reliability of the expert evidence submitted to courts. While in various countries including the USA, Canada and the Netherlands criteria have been introduced which may be used as a form of input or output control on expert evidence, in England and Wales expert evidence is much less likely to be subject to forms of admissibility or reliability testing. Finally, a number of measures are proposed which may go some way to address some of the present concerns over the evaluation of technical and scientific evidence.     

从“科学的代言人”到“当事人的枪手”——专家证人历史沿革与我国现实考察

英美法系在很早以前就认识到了专家在审判中的重要作用，而具有偏向性专家证人则是对抗制的产物。在中世纪，专家是以陪审团成员或者法官顾问的身份出现在法庭上的，由法官进行引导和控制．以保证其中立性和公正性。16世纪，随着知情陪审团被不知情陪审团所替代，法院开始传唤专家出庭，就某个专业问题向陪审团提供意见和结论。到了18世纪．英美法系审判中对抗的因素越来越多．双方当事人开始传唤专家作为各自的证人出庭提供意见。但18世纪末19世纪初的专家证人并不具有偏向性。直到19世纪中期，专家证人开始为各自当事人的利益服务．在法庭上为就与案件事实相关的专门性问题提出自己的意见．现代意义上的专家证人产生。梳理英美法系专家证人的历史对我国司法鉴定制度改革具有重要的指导意义。我国现已全面确立专家辅助人制度．专家辅助人应当具有中立性．并需构建一系列的程序和制度对专家辅助人的中立性进行保障。     

Expert scientific evidence under the adversarial system. A travesty of justice?

The procedures for providing courts with expert scientific evidence under the adversarial and inquisitorial systems are reviewed with special reference to the role of the Home Office as the principal purveyor of such evidence at English law. It is suggested that recent advances in technology must lead to increasing interdependence of the various disciplines involved and that the artificial separations which presently exist, notably between forensic pathology and science, are unsatisfactory. Attention is called to the situation in many European countries where medico-legal institutes provide the courts with comprehensive expert scientific services which are non-confrontational and which do not place experts in the position of appearing for one or other of the parties to an action.     

True paternity or exclusion: analysis in the case of a deceased party

State-of-the-art technology can play a significant role in solving forensic and parentage problem cases if an expert scientist is employed in the analysis and interpretation of test results. As presented in this paper, there are differences of opinion among witnesses examining the same evidence, therefore illustrating the need for careful examination of evidence even by the expert.     

Forensic identification science evidence since Daubert: Part I--A quantitative analysis of the exclusion of forensic identification science evidence

The U.S. Supreme Court decisions in Daubert v. Merrell Dow Pharmaceuticals Inc. and Kumho Tire Co. Ltd. v. Carmichael transformed the way scientific expert evidence was reviewed in courts across the United States. To gauge the impact of these rulings on the admission of forensic identification evidence, the authors analyzed 548 judicial opinions from cases where admission of such evidence was challenged. Eighty-one cases (15%) involved exclusion or limitation of identification evidence, with 50 (65.7%) of these failing to meet the "reliability" threshold. This was largely because of a failure to demonstrate a sufficient scientific foundation for either the technique (27 cases) or the expert's conclusions (17 cases). The incidence of exclusion/limitation because of a lack of demonstrable reliability suggests that there is a continuing need for the forensic sciences to pursue research validating their underlying theories and techniques of identification to ensure their continued acceptance by the courts.     

刑事鉴定制度修改的背景、争议及解读

《刑事诉讼法》在鉴定问题上进行了大幅度地修改,改变了鉴定作为证据种类的名称,删除了"省级人民政府指定的医院"的规定,增加了对鉴定人出庭作证及其人身权利保障等内容,其进步意义应当是肯定的。然而,《刑事诉讼法》有关鉴定修改触及的内容均需要从修改的缘故、争议问题被修改的程度以及执行中可能遇到的障碍等方面予以理论分析与诠释,以便对此问题有一个科学的认识与理解。     

法庭语音学

本文对法庭语音学进行了研究综述,主要介绍了该学科的核心内容：说话人鉴定。在实际办案中,当未找到嫌疑人,只有犯罪分子的检材语音时,可以使用说话人画像/说话人分类技术。若没有犯罪分子的录音证据时,可以让受害人和证人进行说话人的听觉辨认。具体的辨认形式有两种：对熟人辨认和对陌生人辨认,在对陌生人辨认时可以采用语音辨认的方法进行。当检材语音和样本语音都齐备的时候,法庭语音分析专家就可以对二者进行比对检验了。目前语音比对分析涉及到的问题和领域有：基于贝叶斯方法的法庭推理和似然比计算、共振峰频率的测量应用、非解析感知与样例理论、法庭说话人自动识别以及不同方法的综合应用等。     

The contribution of forensic science to crime analysis and investigation: forensic intelligence

The debate in forensic science concentrates on issues such as standardisation, accreditation and de-contextualisation, in a legal and economical context, in order to ensure the scientific objectivity and efficiency that must guide the process of collecting, analysing, interpreting and reporting forensic evidence. At the same time, it is recognised that forensic case data is still poorly integrated into the investigation and the crime analysis process, despite evidence of its great potential in various situations and studies. A change of attitude is needed in order to accept an extended role for forensic science that goes beyond the production of evidence for the court. To stimulate and guide this development, a long-term intensive modelling activity of the investigative and crime analysis process that crosses the boundaries of different disciplines has been initiated. A framework that fully integrates forensic case data shows through examples the capital accumulated that may be put to use systematically.     

Educating Jurors about Forensic Evidence: Using an Expert Witness and Judicial Instructions to Mitigate the Impact of Invalid Forensic Science Testimony

Invalid expert witness testimony that overstated the precision and accuracy of forensic science procedures has been highlighted as a common factor in many wrongful conviction cases. This study assessed the ability of an opposing expert witness and judicial instructions to mitigate the impact of invalid forensic science testimony. Participants (N = 155) acted as mock jurors in a sexual assault trial that contained both invalid forensic testimony regarding hair comparison evidence, and countering testimony from either a defense expert witness or judicial instructions. Results showed that the defense expert witness was successful in educating jurors regarding limitations in the initial expert's conclusions, leading to a greater number of not-guilty verdicts. The judicial instructions were shown to have no impact on verdict decisions. These findings suggest that providing opposing expert witnesses may be an effective safeguard against invalid forensic testimony in criminal trials.     

A logical framework to ballpoint ink dating interpretation

Since its beginnings, the forensic field of questioned documents has been concerned with the dating of inks. Ink ageing processes follow complex paths. Disagreements about the feasibility of current methods have been voiced worldwide among the scientific and legal communities. This controversy has been the starting point of the present work. Its aim was that of evaluating the interpretation processes of such evidence. Subjective statistical data have been assigned from earlier works and illustrate the kind of data necessary to date ballpoint ink, and how to use it for this purpose. This work also suggests that the court and scientific requirements for standards of reliability are not yet fulfilled by actual ink dating methods for regulatory use in expert testimony.