Assessing Class Consistency and Common Source Using 3D Virtual Comparison Microscopy in Firearm Forensics

Over the past several years, advances in 3D surface metrology have made their way into the field of firearm and tool mark analysis. Accurate surface imaging coupled with high-resolution visualization tools and advanced algorithms are beginning to allow examiners to view, annotate, and share data between labs, to conduct blind verification, and to form a statistical basis for identification. This proposal aims to continue research and development within the discipline of Virtual Comparison Microscopy (VCM) for firearm forensics by addressing three NIST OSAC research needs. First, we will conduct a study to understand examiner consistency in class and sub-class labeling. Second, we will complete a VCM version of an Isolated Pairs study for which traditional comparison microscopy results have already been obtained. The proposed work includes critical steps towards further validating the field of toolmark examination and the use of 3D scanning technology in and around the forensic lab. The proposed aims directly address three of the NIST OSAC defined research needs. First, it assesses examiners' ability to consistently categorize evidence by class characteristics and to identify potential subclass marks. Second, the research adds to growing evidence on how examiners utilize a five-point range of conclusions scale. OSAC recognizes that in addition to false positives and false negatives it's important to understand how the three levels of inconclusive are utilized by the firearm and toolmark community. Finally, and more generally, OSAC recognizes the need for additional error-rate studies. The proposed aims add to our work in establishing VCM error rates. Taken together the aims of this proposal address several published NIST OSAC research aims and represent important next steps for both VCM and the discipline of Firearm and Toolmark Examination. The work directly addresses the CFDA 16.560 solicitation's Development goal of producing novel and useful systems and methods and the Fundamental/Basic Research Goals of improving the understanding of the accuracy, reliability, and measurement validity of forensic science disciplines. Note: This project contains a research and/or development component, as defined in applicable law, and complies with Part 200 Uniform Requirements - 2 CFR 200.210(a)(14). CA/NCF