We are working to improve the scientific infrastructure for objective forensic firearm and toolmark identification. We focus on the development of measurement methods, objective comparison metrics, and rigorous procedures to obtain quantitative uncertainty estimates for forensic conclusions. This work is part of the project's general mission to advance traceable surface topography measurements in the U.S. by developing methods to characterize and reduce measurement uncertainty and by providing best-in-class calibrations, standard reference materials (SRMs), and reference software.
Surface topography affects the functionality of manufactured parts. To control surface topography, industry requires increasingly advanced measurement methods.
Forensic firearm and toolmark identification is based on comparing the surface topography of forensic samples, such as fired bullets and ejected cartridge cases. The examiner typically must determine whether microscopic marks on compared surfaces were made by the same firearm or tool. This determination is challenging, not only because there are differences between marks generated by the same firearm, but also because there are possible similarities between marks generated by different firearms. There is a fundamental need in forensics for objective, quantitative methods to evaluate the similarity between evidence and reference surfaces so that objective decisions about common origin can be made with uncertainty statements. Therefore: