The Error in “Error Rate”: Why Error Rates Are So Needed,Yet So Elusive

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.     

物证鉴定的能力验证

能力验证是物证鉴定质量保障体系的重要组成部分,可以非常有效的评估、监控和提高实验室物证鉴定能力和质量。本文论述了物证鉴定能力验证的主要方法、形式、类型和特点,以及在物证鉴定实验室质量管理中的具体应用,介绍了国外物证鉴定实验室参加能力验证活动的历史和现状,并提出在我国物证鉴定实验室广泛开展能力验证活动的思考。     

电子数据司法鉴定能力验证的设计与分析——以2021年电子数据功能性鉴定为例

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。     

国外法庭科学DNA实验室的质量保证和质量控制现状

法庭科学DNA检测飞速发展和广泛应用的同时也面临巨大风险,实验室质量保证能力和质量控制手段的不足已开始影响到法庭科学DNA检测的证据地位。本文对国外法庭科学DNA实验室的有关情况进行初步分析,从中发掘有益的启示,为我国法庭科学DNA检测的改革和发展提供借鉴。     

法庭科学痕迹检验实验室质量控制的现状及进展

痕迹检验实验室作为法庭科学实验室的重要组成部分,其质量控制活动在遵循普遍原则的基础上,根据自身专业特性,在质量控制方法选择及活动实施上有所侧重.本文在调研国内外关于痕迹检验实验室质量控制研究与实践的基础上,从结果质量控制、人员资格和培训、方法确认、记录、结果报告、出庭等方面对痕迹检验实验室质量控制要求及现状进行综述,旨在探索痕迹检验实验室的质量控制关键技术,尽快建立国内痕迹检验实验室质量控制规范.     

物证鉴定的技术方法确认和标准操作规程

物证鉴定中使用的技术方法直接影响和决定了物证检验结果的质量,因此对技术方法的管理是物证鉴定实验室质量保证体系的核心因素之一。开展技术方法的开发确认和内部确认并建立方法的标准操作规程,是保证实验室能够正确选择和使用科学可靠的技术方法,并获得一致结果的主要手段。运行高水平质量保证体系的物证鉴定实验室,应该在案件物证检验工作中使用经过实验室内部确认的技术方法,而且重要新技术方法还应在开发确认基础上进行内部确认,根据方法确认结果建立该方法的标准操作规程。     

Results of a proposed breath alcohol proficiency test program

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.     

法医精神病学能力验证相关问题探讨

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.     

论司法鉴定人资格认证框架的构建

通过对我国司法鉴定人资格管理中存在的问题分析,在借鉴相关行业管理模式的基础上,以国际标准化组织发布的ISO/IEC17024准则为指导.提出将人员认证与鉴定人职业资格相结合,将资格考试和能力验证作为鉴定人认证的主要评价手段,尝试在现有法律制度和管理模式下构建我国司法鉴定人资格认证的基本框架.     

Considerations on the ASTM Standards 1789‐04 and 1422‐05 on the Forensic Examination of Ink

Abstract: The ASTM standards on Writing Ink Identification (ASTM 1789‐04) and on Writing Ink Comparison (ASTM 1422‐05) are the most up‐to‐date guidelines that have been published on the forensic analysis of ink. The aim of these documents is to cover most aspects of the forensic analysis of ink evidence, from the analysis of ink samples, the comparison of the analytical profile of these samples (with the aim to differentiate them or not), through to the interpretation of the result of the examination of these samples in a forensic context. Significant evolutions in the technology available to forensic scientists, in the quality assurance requirements brought onto them, and in the understanding of frameworks to interpret forensic evidence have been made in recent years. This article reviews the two standards in the light of these evolutions and proposes some practical improvements in terms of the standardization of the analyses, the comparison of ink samples, and the interpretation of ink examination. Some of these suggestions have already been included in a DHS funded project aimed at creating a digital ink library for the United States Secret Service.     

Quality assurance testing of an explosives trace analysis laboratory--further improvements

The Forensic Explosives Laboratory (FEL) operates within the Defence Science and Technology Laboratory (DSTL) which is part of the UK Government Ministry of Defence (MOD). The FEL provides support and advice to the Home Office and UK police forces on matters relating to the criminal misuse of explosives. During 1989 the FEL established a weekly quality assurance testing regime in its explosives trace analysis laboratory. The purpose of the regime is to prevent the accumulation of explosives traces within the laboratory at levels that could, if other precautions failed, result in the contamination of samples and controls. Designated areas within the laboratory are swabbed using cotton wool swabs moistened with ethanol water mixture, in equal amounts. The swabs are then extracted, cleaned up and analyzed using Gas Chromatographs with Thermal Energy Analyzer detectors. This paper follows on from a previous published paper describing the regime and summarizing subsequent results from approximately 6 years of tests. Lessons learned and improvements made over the period are also discussed. Monitoring samples taken from surfaces within the trace laboratories and trace vehicle examination bay have, with few exceptions, revealed only low levels of contamination, predominantly of RDX. Analysis of the control swabs, processed alongside the monitoring swabs, has demonstrated that in this environment the risk of forensic sample contamination, assuming all the relevant anti-contamination procedures have been followed, is so small that it is considered to be negligible. The monitoring regime has also been valuable in assessing the process of continuous improvement, allowing sources of contamination transfer into the trace areas to be identified and eliminated.     

法庭科学实验室质量控制研究综述

本文对法庭科学实验室质量控制活动的历史进行了回顾性分析研究,对国内外现状进行了归纳性综述。通过国内外比较,指出了我国法庭科学实验室质量控制活动的差距与改进建议。     

从CTS能力验证计划看纤维物证检验的发展趋势

本文通过对2006年以来CTS法庭科学领域纤维测试项目结果的分析,总结了国内外纤维物证检验的技术方法,并对纤维物证检验的发展趋势进行了展望。