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.     

中世纪欧洲法医学溯源

法医学是应用病理学、生物学、生物化学和其他医学科学理论和技能解决法律问题,为侦查和审判提供证据的科学。法医学学科属性是医学,其目的是解决法律问题,因而法医学同时具有自然科学和人文科学属性。现今,我们对于法医学的研究往往局限在自然科学领域,而对其人文学科属性却有所忽视。当代西方法医学起源自中世纪的欧洲大陆,当时罗马法和教会法占统治地位,它们没有设立陪审团制度,而且允许对嫌疑人进行刑讯逼供,而英美法系的司法审判程序设立了陪审团制度。在这两种司法体制下,法医医学证言、证词逐步形成了两种形式：英美法系控诉式诉讼体制下的言辞证据形式和罗马法诉讼中纠问体制下的书证形式。本文将对中世纪欧洲的法医学进行溯源研究,从欧洲法医学的起源和发展角度,完善法医学史研究内容,为世界法医学史比较研究提供借鉴。     

Forensic identification science evidence since Daubert: Part II--judicial reasoning in decisions to exclude forensic identification evidence on grounds of reliability

Many studies regarding the legal status of forensic science have relied on the U.S. Supreme Court's mandate in Daubert v. Merrell Dow Pharmaceuticals Inc., and its progeny in order to make subsequent recommendations or rebuttals. This paper focuses on a more pragmatic approach to analyzing forensic science's immediate deficiencies by considering a qualitative analysis of actual judicial reasoning where forensic identification evidence has been excluded on reliability grounds since the Daubert precedent. Reliance on general acceptance is becoming insufficient as proof of the admissibility of forensic evidence. The citation of unfounded statistics, error rates and certainties, a failure to document the analytical process or follow standardized procedures, and the existence of observe bias represent some of the concerns that have lead to the exclusion or limitation of forensic identification evidence. Analysis of these reasons may serve to refocus forensic practitioners' testimony, resources, and research toward rectifying shortfalls in these areas.     

Considering forensic science: individual differences,opposing expert testimony and juror decision making

Two experimental studies examined the effect of opposing expert testimony on perceptions of the reliability of unvalidated forensic evidence (anthropometric facial comparison). In the first study argument skill and epistemological sophistication were included as measures of individual differences, whereas study two included scores on the Forensic Evidence Evaluation Bias Scale. In both studies participants were assigned to groups who heard: (1) no expert testimony, (2) prosecution expert testimony, or (3) prosecution and opposing expert testimony. Opposing expert testimony affected verdict choice, but this effect was mediated by perceptions of reliability of the initial forensic expert's method. There was no evidence for an effect on verdict or reliability ratings by argument skill or epistemology. In the second experiment, the same mediation effect was found, however scores on one subscale from the FEEBS and age also affected both verdict and methodological reliability. It was concluded that opposing expert testimony may inform jurors, but perceptions of the reliability of forensic evidence affect verdict, and age and bias towards forensic science influence perceptions of forensic evidence. Future research should investigate individual differences that may affect perception or bias towards forensic sciences under varying conditions of scientific reliability.     

The Testimony of Forensic Identification Science: What Expert Witnesses Say and What Factfinders Hear

This research examined how variations in the presentation of forensic science information affect factfinders’ judgments in a trial. Participants read a summary of a murder case, the critical testimony being the results of a microscopic hair comparison given by a forensic expert. Across two experiments we manipulated how the expert expressed his results, whether he gave an explicit conclusion concerning identity of the hair, and whether the limitations of forensic science were expressed during trial. Qualitative testimony was more damaging to the defense than quantitative testimony, conclusion testimony increased the defendant’s culpability ratings when findings were presented quantitatively, and expressing limitations of forensic science had no appreciable effect. Results are discussed in terms of factfinders’ interpretation of forensic identification evidence.     

The importance of forensic evidence for decisions on criminal guilt

Recent studies have found that the general public perceives forensic evidence to be relatively inaccurate and to involve high levels of human judgement. This study examines how important the general public finds forensic evidence by comparing decisions on guilt and punishment in criminal cases that involve forensic versus eyewitness testimony evidence and examining whether a CSI effect exists. Specifically, this experimental survey study utilized a 2 (crime type: murder or rape) × 4 (evidence type: DNA, fingerprint, victim eyewitness testimony, or bystander eyewitness testimony) ? 1 (no victim testimony for murder scenario) design, yielding seven vignettes scenarios to which participants were randomly assigned. Results indicate that forensic evidence was associated with more guilty verdicts and higher confidence in a guilty verdict. Forensic evidence did not change the expected sentence length and did not generally affect the ideal sentence length. However, for rape, respondents believed that the defendant should receive a longer sentence when forensic evidence was presented but forensic evidence did not alter likely sentence that respondents expected the defendant to receive. The results of this study did not support a CSI effect. Overall, this study suggests that forensic evidence – particularly DNA – has a stronger influence during the verdict stage than the sentencing stage.     

Expert Testimony Using the Rorschach Performance Assessment System in Psychological Injury Cases

The Rorschach Performance Assessment System (R-PAS; Meyer et al. 2011) is a new system for administering, scoring, and interpreting the Rorschach Inkblot Test that is designed to make the best possible use of currently available scientific and clinical evidence. Many features of R-PAS are well-suited to forensic evaluation generally and to psychological evaluations in psychological injury cases in particular. Among them, R-PAS: (a) offers an alternative to self-report methods that adds incremental validity, (b) provides a useful check against exaggerated or minimized symptom presentation, (d) generates evidence concerning implicit traits and behavioral tendencies, (e) offers techniques for adjusting for abnormal response sets, (f) uses internationally applicable reference data that do not exaggerate or minimize pathology, (g) organizes results according to the strength of the evidence, and (h) presents results on which are interpretations are based in a manner easy for the intelligent layperson to grasp. Despite its recent formal introduction to the professional assessment community, R-PAS takes advantage of decades of research in peer-reviewed publications (including the insights of Rorschach critics) and builds on established validity and general acceptance for most of its procedures and features. The article describes the standards and criteria applying to expert psychological testimony in U.S. federal and state courts and applies them to Rorschach-based testimony in general and R-PAS-based testimony specifically. It is argued that when the system is properly used and applied and when such testimony is appropriately formulated, it should be found admissible in both state and federal courtrooms     

Error Rates,Likelihood Ratios,and Jury Evaluation of Forensic Evidence

Forensic examiners regularly testify in criminal cases, informing the jurors whether crime scene evidence likely came from a source. In this study, we examine the impact of providing jurors with testimony further qualified by error rates and likelihood ratios, for expert testimony concerning two forensic disciplines: commonly used fingerprint comparison evidence and a novel technique involving voice comparison. Our method involved surveying mock jurors in Amazon Mechanical Turk (N = 897 laypeople) using written testimony and judicial instructions. Participants were more skeptical of voice analysis and generated fewer “guilty” decisions than for fingerprint analysis (B = 2.00, OR = 7.06, p = <0.000). We found that error rate information most strongly decreased “guilty” votes relative to no qualifying information for participants who heard fingerprint evidence (but not those that heard voice analysis evidence; B = −1.16, OR = 0.32, p = 0.007). We also found that error rates and conclusion types led to a greater decrease on “guilty” votes for fingerprint evidence than voice evidence (B = 1.44, OR = 4.23, p = 0.021). We conclude that these results suggest jurors adjust the weight placed on forensic evidence depending on their prior views about its reliability. Future research should develop testimony and judicial instructions that can better inform jurors of the strengths and limitations of forensic evidence.     

Forensic Confirmation Bias: Do Jurors Discount Examiners Who Were Exposed to Task-Irrelevant Information?*†

Knowledge of task-irrelevant information influences judgments of forensic science evidence and thereby undermines their probative value (i.e., forensic confirmation bias). The current studies tested whether laypeople discount the opinion of a forensic examiner who had a priori knowledge of biasing information (i.e., a defendant's confession) that could have influenced his opinion. In three experiments, laypeople (N = 765) read and evaluated a trial summary which, for some, included testimony from a forensic examiner who was either unaware or aware of the defendant's confession, and either denied or admitted that it could have impacted his opinion. When the examiner admitted that the confession could have influenced his opinion, laypeople generally discounted his testimony, as evidenced by their verdicts and other ratings. However, when the examiner denied being vulnerable to bias, laypeople tended to believe him—and they weighted his testimony as strongly as that of the confession-unaware examiner. In short, laypeople generally failed to recognize the superiority of forensic science judgments made by context-blind examiners, and they instead trusted examiners who claimed to be impervious to bias. As such, our findings highlight the value of implementing context management procedures in forensic laboratories so as not to mislead fact-finders.     

Impact of hypnotic testimony on the jury

In the past decade, the forensic use of hypnosis to enhance the memories of victims, witnesses, and defendants has sharply increased. A great deal of controversy surrounds this issue. Some commentators argue that testimony derived from hypnosis should not be allowed as evidence because of its inherent unreliability and the unduly powerful impact it may have on a jury. In the present research, we used a jury simulation technique to study the impact that a hypnotically refreshed witness has upon jurors' decision making. A major finding is that jurors view hypnotic testimony with a certain amount of skepticism. In some respects, its impact is comparable to that of testimony based on delayed recall, and rarely does it have the impact of testimony from an immediate report. In addition, jurors' judgments about hypnotically refreshed testimony affected the way they evaluated other evidence at trial: Jurors who learned that a prosecution witness had been hypnotized were less believing ofother prosecution witnesses than were jurors not exposed to hypnotic testimony. The forensic application of these findings is discussed.This research was supported by a grant from the National Science Foundation, Law and Social Sciences Program. We thank Jane Goodman, Doug Leber, Bonnie Sawnson, Russ Wade, Karen Guest, Jonna Barsanti, Don Kline, Elaine Sullivan, and David Kuykendall for their help at various stages of the project.     

Wrongful convictions and claims of false or misleading forensic evidence

The results are reported of a study to examine case factors associated with 732 wrongful convictions classified by the National Registry of Exonerations as being associated with “False or Misleading Forensic Evidence.” A forensic error typology has been developed to provide a structure for the categorization and coding of factors relating to misstatements in forensic science reports; errors of individualization or classification; testimony errors; issues relating to trials and officers of the court; and evidence handling and reporting issues. This study, which included the analysis of 1391 forensic examinations, demonstrates that most errors related to forensic evidence are not identification or classification errors by forensic scientists. When such errors are made, they are frequently associated with incompetent or fraudulent examiners, disciplines with an inadequate scientific foundation, or organizational deficiencies in training, management, governance, or resources. More often, forensic reports or testimony miscommunicate results, do not conform to established standards, or fail to provide appropriate limiting information. Just as importantly, actors within the broader criminal justice system—but not under the purview of any forensic science organization—may contribute to errors that may be related to the forensic evidence. System issues include reliance on presumptive tests without confirmation by a forensic laboratory, use of independent experts outside the administrative control of public laboratories, inadequate defense, and suppression or misrepresentation of forensic evidence by investigators or prosecutors. In approximately half of wrongful convictions analyzed, improved technology, testimony standards, or practice standards may have prevented a wrongful conviction at the time of trial.     

DNA evidence in South Africa: Lessons learned to date

A trend was noted over the past 15 years in the South African courts. This trend has a multi-factorial origin and highlights the problems faced in the use of forensic science evidence in court. Although there have been improvements on how DNA evidence is gathered and presented in court, due to the fact that certain cases have been contested at the DNA evidence level, multiple issues remain that have not yet been addressed when DNA evidence is submitted to court. These issues include: accreditation, regulation of the forensic science profession, continued education, training of court officials, quality assurance, biased testimony, lack of transparency with regard to processes and procedures followed in the forensic community, incorrect interpretation of DNA evidence, lack of scientific knowledge (including the scientific method) by DNA experts, awareness by the legal profession and an over emphasis on the prosecuting perspective. These same aspects continue to plague current cases. Despite the above, the window of opportunity to address the above has not yet passed. However, it will take continuous and concerted efforts from the scientific and legal professions to bring about the appropriate change to facilitate justice for all in South Africa.     

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 current status of forensic science laboratory accreditation in Europe

Forensic science is gaining some solid ground in the area of effective crime prevention, especially in the areas where more sophisticated use of available technology is prevalent. All it takes is high-level cooperation among nations that can help them deal with criminality that adopts a cross-border nature more and more. It is apparent that cooperation will not be enough on its own and this development will require a network of qualified forensic laboratories spread over Europe. It is argued in this paper that forensic science laboratories play an important role in the fight against crime. Another, complimentary argument is that forensic science laboratories need to be better involved in the fight against crime. For this to be achieved, a good level of cooperation should be established and maintained. It is also noted that harmonization is required for such cooperation and seeking accreditation according to an internationally acceptable standard, such as ISO/IEC 17025, will eventually bring harmonization as an end result. Because, ISO/IEC 17025 as an international standard, has been a tool that helps forensic science laboratories in the current trend towards accreditation that can be observed not only in Europe, but also in the rest of the world of forensic science. In the introduction part, ISO/IEC 17025 states that "the acceptance of testing and calibration results between countries should be facilitated if laboratories comply with this international standard and if they obtain accreditation from bodies which have entered into mutual recognition agreements with equivalent bodies in other countries using this international standard." Furthermore, it is emphasized that the use of this international standard will assist in the harmonization of standards and procedures. The background of forensic science cooperation in Europe will be explained by using an existing European forensic science network, i.e. ENFSI, in order to understand the current status of forensic science in Europe better. The Council of Europe and the European Union approaches to forensic science will also be discussed by looking at the legal instruments and documents published by these two European organizations. Data collected from 52 European forensic science laboratories will be examined and findings will be evaluated from a quality assurance and accreditation point of view. The need for harmonization and accreditation in forensic science will be emphasized. The steps that should be taken at the European level for increasing and strengthening the role of European forensic science laboratories in the fight against crime will be given as recommendations in the conclusion.     

美国法庭科学证据的应用与发展

＂法庭科学＂萌芽于古代中国,兴盛于近现代西方国家,最终发展成为具备完整科学体系的现代意义上的法庭科学学科。法庭科学证据的应用与发展显然与法庭科学的发展与应用密切相关,它们相互制约,相互促进。美国司法制度中关于法庭科学证据的证明力、可信度、可采性的分立质疑对法庭科学本身的发展无疑起到鞭策与促进作用。美国法庭科学证据的司法制度以及常用的一些传统与高技术法庭科学证据的使用过程中存在的许多问题,理解法庭科学证据标准,对我国法庭科学及其证据的研究与应用有所启迪。     

法证科学领域的决策

随着法证DNA证据以及它所适用的概率模型日益凸显,反映了传统法证科学的局限性,并使人们对法证科学领域的决策产生了越来越多的质疑,焦点集中在对结论的解读方式和实际运用。分析表明,科学证据的本质不是绝对性或确定性的,而是概率性的;同时,事实审判者需要基于这些概率性的证据对事实作出明确的决定。因此,对于法证科学领域的决策,应当是专家在一系列归纳得出的特定假设基础上,就研究结果的概率进行恰当的报告,由事实审判者承担对概率作出决断的任务。     

《刑事诉讼法》有关鉴定问题的修改与评价

《刑事诉讼法修正案》就鉴定意见作为证据的名称、省政府指定医院、鉴定人出庭的法律后果、鉴定人人身保障以及有专门知识的人出庭协助公诉人、当事人和辩护人、诉讼代理人就鉴定意见提出意见等方面作出了修改,其意义是不可低估的。同时,由于修改的内容在前瞻性上不明显,有些重要的问题,如鉴定启动权、强制鉴定等没有涉及,仍需要司法鉴定制度改革予以进一步完善与弥补。     

抓住机遇 迎接挑战 谋求发展——《刑诉法修正案（草案）》关于鉴定结论等问题的新变化

《刑事诉讼法修正案（草案）》将于2012年3月提交全国人大审议通过。其中对鉴定结论作了科学定位,对鉴定人出庭作证及拒不出庭的法律后果作出了有别于普通证人的明确规定。这是由鉴定证据的特殊性和鉴定人的特殊身份所决定的。这对司法鉴定机构及从业人员既是挑战,又是机遇;应当抓住机遇,迎接挑战,谋求发展。     

Effective use of forensic science in volume crime investigations: Identifying recurring themes in the literature

New scientific, technological and legal developments, particularly the introduction of national databases for DNA and fingerprints, have led to increased use of forensic science in the investigation of crime. There is an assumption, and in some instances specific assertions, that such developments bring improvements either in broad criminal justice terms or more narrowly in terms of economic or practical efficiencies. The underlying presumption is that the new technological opportunities will be understood and effectively implemented. This research investigates whether such increases in activity have also been accompanied by improvements in the effective use of forensic science. A systematic review of thirty-six reports published (predominantly in England and Wales) since the 1980s, which have considered the use of forensic science in the investigation of volume crimes, was carried out. These reports have identified a number of recurrent themes that influenced how effectively forensic science was used in investigations. The themes identified included forensic knowledge and training of investigators, communication and information exchange between specialists and investigators, timeliness of forensic results, interagency relationships and deployment of crime scene examiner resources. The research findings suggest that these factors continue to hinder the effective use of forensic science despite technological advances and this paper considers their potential causes.     

论在医疗纠纷诉讼中推行专家辅助人制度

医学专家意见在医疗纠纷诉讼中占有重要地位，在不同法系国家分别以鉴定和专家证言的形式出现在法庭诉讼中。目前，我国已形成了以医疗事故技术鉴定和医疗过错鉴定为主体的医疗专业技术鉴定体制，但当前面临着诸多困境。从专家证据制度改革和医学专家意见形成特点等层面分析，专家辅助人制度与普通法系国家专家证人制度类似．其和鉴定制度的有机结合可以在医疗纠纷诉讼领域构建更为理想的专家证据制度：有助于最大限度地使法律真实靠近客观真实。但过于强大的医疗专业技术鉴定制度对专家辅助人制度具有明显的压制作用．因此需适当限制鉴定制度，大力推行专家辅助人制度，同时应总结相关国家经验教训。防止专家辅助人制度产生不应有的负面效应。