Corzo Ruthmara, Hoffman Tricia, Ernst Troy, Trejos Tatiana, Berman Ted, Coulson Sally, Weis Peter, Stryjnik Aleksandra, Dorn Hendrik, Pollock Edward Chip, Workman Michael Scott, Jones Patrick, Nytes Brendan, Scholz Thomas, Xie Huifang, Igowsky Katherine, Nelson Randall, Gates Kris, Gonzalez Jhanis, Voss Lisa-Mareen, Almirall Jose
Florida International University, Miami, FL, United States.
National Institute of Standards and Technology, Gaithersburg, MD, United States.
Forensic Chem. 2021 Mar;22. doi: 10.1016/j.forc.2021.100307.
Seventeen laboratories participated in three interlaboratory exercises to assess the performance of refractive index, micro X-ray Fluorescence Spectroscopy (μXRF), and Laser Induced Breakdown Spectroscopy (LIBS) data for the forensic comparison of glass samples. Glass fragments from automotive windshields were distributed to the participating labs as blind samples and participants were asked to compare the glass samples (known vs. questioned) and report their findings as they would in casework. For samples that originated from the same source, the overall correct rate was greater than 92% for each of the three techniques (refractive index, μXRF, and LIBS). For samples that originated from different vehicles, an overall correct rate of 82%, 96%, and 87% was observed for refractive index, μXRF, and LIBS, respectively. Special attention was given to the reporting language used by practitioners as well as the use of verbal scales and/or databases to assign a significance to the evidence. Wide variations in the reported conclusions exist between different laboratories, demonstrating a need for the standardization of the reporting language used by practitioners. Moreover, few labs used a verbal scale and/or a database to provide a weight to the evidence. It is recommended that forensic practitioners strive to incorporate the use of a verbal scale and/or a background database, if available, to provide a measure of significance to glass forensic evidence (i.e., the strength of an association or exclusion).
17个实验室参与了三项实验室间比对活动，以评估折射率、微X射线荧光光谱法（μXRF）和激光诱导击穿光谱法（LIBS）数据在玻璃样本法医比对中的性能。来自汽车挡风玻璃的玻璃碎片作为盲样分发给参与实验室，要求参与者对玻璃样本（已知样本与可疑样本）进行比对，并按照实际案件工作那样报告他们的发现。对于来自同一来源的样本，三种技术（折射率、μXRF和LIBS）各自的总体正确率均大于92%。对于来自不同车辆的样本，折射率、μXRF和LIBS的总体正确率分别为82%、96%和87%。特别关注了从业者使用的报告语言以及使用文字量表和/或数据库来赋予证据重要性的情况。不同实验室之间报告的结论存在很大差异，这表明需要对从业者使用的报告语言进行标准化。此外，很少有实验室使用文字量表和/或数据库来衡量证据的分量。建议法医从业者努力采用文字量表和/或背景数据库（如果有的话），以衡量玻璃法医证据的重要性（即关联或排除的强度）。
