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Blind proficiency testing is ideal for testing crime laboratory personnel because the elements of analyst bias and anticipation are removed. However, sending proficiency tests through the laboratory system as real casework is difficult. The substantial challenges with preparing and administering blind tests may prevent laboratory managers from initiating blind testing. In 2015, the Harris County Institute of Forensic Sciences committed to improving its crime laboratory’s proficiency testing program by adding blind tests. The goal was to test the whole system, from evidence receipt to report release. With careful planning, trial-and-error, and ongoing assessment of available resources, not only was the program proven to be feasible, but there was also clear understanding of how to optimize our program. In this article, we share our experiences, lessons learned, and program details to assist other forensic service providers with developing their own blind testing programs, which would ultimately lead to improved quality assurance. 相似文献
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The ISO/IEC 17020 and 17025 standards both include requirements for impartiality and the freedom from bias. Meeting these requirements for implicit cognitive bias is not a simple matter. In this article, we address these international standards, specifically focusing on evaluating and mitigating the risk to impartiality, and quality assurance checks, so as to meet accreditation program requirements. We cover their meaning to management as well as to practitioners, addressing how these issues of impartiality and bias relate to forensic work, and how one can effectively evaluate and mitigate those risks. We then elaborate on specific quality assurance policies and checks and identify when corrective action may be appropriate. These measures will not only serve to meet ISO/IEC 17020 and 17025 requirements, but also enhance forensic work and decision-making. 相似文献
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Brett O. Gardner Ph.D. Sharon Kelley J.D. Ph.D. Karen D. H. Pan M.S. 《Journal of forensic sciences》2020,65(2):450-457
Proficiency testing is a key component of quality assurance programs within crime laboratories and can help improve laboratory practices. However, current proficiency testing procedures contain significant limitations and can be misinterpreted by examiners and court personnel (Garrett & Mitchell, 2018). To evaluate some of these limitations, we surveyed latent print examiners (n = 198) after they completed a Collaborative Testing Services, Inc. proficiency test. Additionally, we evaluated test performance and used a quality metric algorithm to evaluate the quality of test prints. Results do not suggest that respondents are dissimilar to the broader examiner population, although they may engage in different behaviors when completing tests versus casework. Findings show that proficiency testing contains prints of high quality and is perceived as both relatively easy and representative of casework. The test discriminated between inexperienced and experienced respondents, and verification procedures were largely ineffective in reducing errors. Objective quality metrics may provide a path forward to improving proficiency testing in a measurable manner. 相似文献
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电子数据鉴定作为司法程序中的重要环节,对于确保鉴定流程的规范性和鉴定意见的正确性,以及维护司法公正具有重要意义。针对电子数据司法鉴定实验室,能力验证是一种有效的质量控制与改进手段。电子数据功能性鉴定作为电子数据鉴定的重要组成部分,有必要利用能力验证进行质量控制。通过梳理2021年电子数据功能性鉴定能力验证(2021SF-CNAS 034)结果,阐述电子数据功能性鉴定过程中应注意的相关事项,分析国内该领域行业及地域的发展现状、参加机构的鉴定结果准确性以及鉴定方法和鉴定工具的使用情况,进一步探讨目前该领域能力验证存在的问题,总结出可采取的相应措施,并对该领域的未来发展方向进行了展望。 相似文献
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Itiel E. Dror Ph.D. 《Journal of forensic sciences》2020,65(4):1034-1039
Establishing error rates is crucial for knowing how well one is performing, determining whether improvement is needed, measuring whether interventions are effective, as well as for providing transparency. However, the flurry of activities in establishing error rates for the forensic sciences has largely overlooked some fundamental issues that make error rates a problematic construct and limit the ability to obtain a meaningful error rate. These include knowing the ground truth, establishing appropriate databases, determining what counts as an error, characterizing what is an acceptable error rate, ecological validity, and transparency within the adversarial legal system. Without addressing these practical and theoretical challenges, the very notion of a meaningful error rate is limited. 相似文献
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Abstract: Two major variations of polygraph “Control Question” testing, the Zone Comparison (ZoC) and the Modified General Question Test (MGQT) were evaluated. Within each, the type of control question, Exclusive or “time bar” (e.g., “Before you were 21, did you ever...”) and Nonexclusive or “no time bar”(e.g., “Did you ever….?”) was manipulated in a mock theft scenario, with 80 male and 40 female subjects randomly assigned to be either innocent or guilty. Polygraphic data collected by experienced field examiners were numerically scored by an evaluator blind to all aspects of the study. Decision accuracy was not related to the type of procedure (ZoC/MGQT) used or the subject’s sex. Accuracy was significantly related to the type of control question [χ2(2) = 11.46, p = 0.003; τc = 0.29]. Nonexclusive control questions produced greater accuracy than Exclusive control questions on both innocent and guilty subjects. These results and subjects’ self‐reports support the general “theory” on which control question (CQ) testing is based. The need for better empirical support of accepted dogma and current field practices is strongly indicated by these findings. 相似文献
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Although proficiency test programs have long been used in both clinical and forensic laboratories, they have not found uniform application in forensic breath alcohol programs. An initial effort to develop a proficiency test program appropriate to forensic breath alcohol analysis is described herein. A total of 11 jurisdictions participated in which 27 modern instruments were evaluated. Five wet bath simulator solutions with ethanol vapor concentrations ranging from 0.0254 to 0.2659 g/210 L were sent to participating programs, instructing them to perform n = 10 measurements on each solution using the same instrument. Four of the solutions contained ethanol only and one contained ethanol mixed with acetone. The systematic errors for all instruments ranged from -11.3% to +11.4% while the coefficient of variations ranged from zero to 6.1%. A components-of-variance analysis revealed at least 79% of the total variance as being due to the between-instrument component for all concentrations. Improving proficiency test program development should consider: (1) clear protocol instructions, (2) frequency of proficiency testing, (3) use lower concentrations for determining limits-of-detection and -quantitation, etc. Despite the lack of a biological component, proficiency test participation should enhance the credibility of forensic breath test programs. 相似文献
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Andrea Macarulla Rodriguez M.Sc. Zeno Geradts Ph.D. Marcel Worring Ph.D. 《Journal of forensic sciences》2020,65(4):1169-1183
In this study, we aim to compare the performance of systems and forensic facial comparison experts in terms of likelihood ratio computation to assess the potential of the machine to support the human expert in the courtroom. In forensics, transparency in the methods is essential. Consequently, state-of-the-art free software was preferred over commercial software. Three different open-source automated systems chosen for their availability and clarity were as follows: OpenFace, SeetaFace, and FaceNet; all three based on convolutional neural networks that return a distance (OpenFace, FaceNet) or similarity (SeetaFace). The returned distance or similarity is converted to a likelihood ratio using three different distribution fits: parametric fit Weibull distribution, nonparametric fit kernel density estimation, and isotonic regression with pool adjacent violators algorithm. The results show that with low-quality frontal images, automated systems have better performance to detect nonmatches than investigators: 100% of precision and specificity in confusion matrix against 89% and 86% obtained by investigators, but with good quality images forensic experts have better results. The rank correlation between investigators and software is around 80%. We conclude that the software can assist in reporting officers as it can do faster and more reliable comparisons with full-frontal images, which can help the forensic expert in casework. 相似文献
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能力验证是利用实验室间比对,按照预先制定的准则评价参加者的能力,是世界各国用以评价和保障实验室/机构能力所采用的重要手段.在我国司法鉴定领域,能力验证已逐渐成为执业管理、监督管理的重要手段.根据管理部门的要求,司法鉴定机构应通过参加能力验证活动证明其具有相应的技术能力,并作为内部质量控制、发现问题和持续改进的重要途径.作为公认的主观性较强、风险较高的司法鉴定行业,在法医精神病专业开展能力验证活动更具必要性与迫切性.近几年的运作尝试也表明,在本专业开展能力验证活动是可行的,评价结果亦是行业技术水平的真实反映.但在项目设计与运作上还有完善空间,如样本与物品制备可真实、完备些,可争取更大的技术指导与示范引导作用,应合理控制考核难度,并增强专家公议结果的可靠程度、可接受性,且运作方式应更灵活、多样.参加机构应提高对能力验证的认识,加强业务培训,科学对待;作业时严格遵守作业要求,通读懂材料,寻找关键点,并注重要点与逻辑性,反馈结论要尽量明确、唯一,争取较满意评价结果. 相似文献
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Moshe Kam Ph.D. Pramod Abichandani Ph.D. Tom Hewett Ph.D. 《Journal of forensic sciences》2015,60(4):936-941
This study documents the results of a controlled experiment designed to quantify the abilities of forensic document examiners (FDEs) and laypersons to detect simulations in handwritten documents. Nineteen professional FDEs and 26 laypersons (typical of a jury pool) were asked to inspect test packages that contained six (6) known handwritten documents written by the same person and two (2) questioned handwritten documents. Each questioned document was either written by the person who wrote the known documents, or written by a different person who tried to simulate the writing of the person who wrote the known document. The error rates of the FDEs were smaller than those of the laypersons when detecting simulations in the questioned documents. Among other findings, the FDEs never labeled a questioned document that was written by the same person who wrote the known documents as “simulation.” There was a significant statistical difference between the responses of the FDEs and layperson for documents without simulations. 相似文献
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开展司法鉴定能力验证 确保持续鉴定能力 总被引:1,自引:0,他引:1
本文论述了能力验证活动监控司法鉴定机构和司法鉴定人的持续鉴定能力在司法鉴定质量控制和司法鉴定行业管理中的重要价值,并从理论和实践上阐明了能力验证活动的类型、组织和实施方法。 相似文献
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Chi‐keung Li Ph.D. Janesse Wing‐sze Hui Ph.D. Chi‐Ming Pang Ph.D. 《Journal of forensic sciences》2018,63(5):1556-1560
Stamps and stamp impressions examinations are based on matching defects and design details on the questioned and control samples. These examinations are routinely carried out by document examiners around the world. International proficiency tests for questioned documents examination have been available for decades while similar programs specifically focusing on stamp impressions examination are rare. This study reported a recent proficiency testing program on stamp impressions examination organized by an accredited provider in accordance with ISO/IEC 17043 requirements. Twenty‐four forensic laboratories registered for the program. Apart from giving details on the design and operation of the program, this study also aimed to provide the limitations and difficulties encountered in sample preparations, homogeneity, and stability tests of the testing materials. Various comments and feedbacks received from the participants, particularly in respect of examination approaches, challenges faced by the participants in forming conclusions and their suggestions for further improvement would be evaluated. 相似文献
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Failure of anthropometry as a facial identification technique using high-quality photographs 总被引:2,自引:0,他引:2
Anthropometry can be used in certain circumstances to facilitate comparison of a photograph of a suspect with that of the potential offender from surveillance footage. Experimental research was conducted to determine whether anthropometry has a place in forensic practice in confirming the identity of a suspect from a surveillance video. We examined an existing database of photographic lineups, where one video image was compared against 10 photographs, which has previously been used in psychological research. Target (1) and test (10) photos were of high quality, although taken with a different camera. The anthropometric landmarks of right and left ectocanthions, nasion, and stomion were chosen, and proportions and angle values between these landmarks were measured to compare target with test photos. Results indicate that these measurements failed to accurately identify targets. There was also no indication that any of the landmarks made a better comparison than another. It was concluded that, for these landmarks, this method does not generate the consistent results necessary for use as evidence in a court of law. 相似文献
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Gretchen R. Dabbs Ph.D. Joan A. Bytheway Ph.D. Melissa Connor Ph.D. 《Journal of forensic sciences》2017,62(5):1292-1296
When in forensic casework or empirical research in‐person assessment of human decomposition is not possible, the sensible substitution is color photographic images. To date, no research has confirmed the utility of color photographic images as a proxy for in situ observation of the level of decomposition. Sixteen observers scored photographs of 13 human cadavers in varying decomposition stages (PMI 2–186 days) using the Total Body Score system (total n = 929 observations). The on‐site TBS was compared with recorded observations from digital color images using a paired samples t‐test. The average difference between on‐site and photographic observations was ?0.20 (t = ?1.679, df = 928, p = 0.094). Individually, only two observers, both students with <1 year of experience, demonstrated TBS statistically significantly different than the on‐site value, suggesting that with experience, observations of human decomposition based on digital images can be substituted for assessments based on observation of the corpse in situ , when necessary. 相似文献