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Surveying Practicing Firearm Examiners



Nicholas Scurich, Brandon Garrett, Robert M. Thompson


The comparison of discharged bullets and shell casings by firearm examiners is one of the most conducted forensic analyses. However, little is known empirically about how practicing firearm examiners view and conduct their work, the range of conclusions they typically reach in their casework, how long they spend on comparisons, what practical challenges arise in casework, as well as their views about the potential role that statistics might play in future firearm examinations and expert witness testimony. To address this lacuna, we queried a sample of practicing firearm and toolmark examiners recruited through the online forums of the Association of Firearm and Toolmark Examiners. Principal findings include: the modal response for time spent conducting bullet examinations is 2-4 hours and the modal response for cartridge casings is 1-2 hours; the average participant (median) makes an identification in 65% of casework, makes an elimination in 12% of casework, and an inconclusive in 20% of casework calls; the vast majority of examiners work at laboratories that permit eliminations when class characteristics agree; the industry-wide false positive error rate is 1%, though very few participants could name a study or give a citation for their reported estimate; qualitative responses about the potential role of statistics were mixed, including some quite positive and welcoming of statistical approaches, and some quite negative in opposition to further use of statistical approaches.
Forensic Science International Synergy


Forensic science, firearms and toolmarks examination, expert testimony, error rates, forensic conclusions


Scurich, N. , Garrett, B. and Thompson, R. (2022), Surveying Practicing Firearm Examiners, Forensic Science International Synergy, [online],, (Accessed July 22, 2024)


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Created April 20, 2022, Updated November 29, 2022