Hypothesis Testing of the Critical Underlying Premise of Discernible Uniqueness in Firearms-Toolmarks Forensic Practice

The forensic practice of firearms-toolmarks identification rests on a currently indefensible conceptual foundation of discernible uniqueness of firearms and tools. Similar to the now-defunct forensic practice of comparative bullet-lead analysis that had been admitted for almost four decades in judicial proceedings, there has never been any scientifically acceptable hypothesis testing of the underlying premises required for practice validation. Existing studies in the domain literature typically presented in court testimonies as support for specific source attributions are pervasively and fatally flawed such that they have no external validity for extrapolation to universal assumption. They are, thus, of no value for validation of the critical premise of discernible uniqueness in real-world forensic scenarios and are largely irrelevant to any particular criminal judicial proceeding. A practical solution is offered that would allow a scientifically defensible opinion to be proffered to courts until comprehensive and meaningful hypothesis testing can be conducted by the mainstream scientific community.