Cartridge-Case Examiners' Aversion to True Rejections: A Shocking Problem With Use of the "Inconclusive" Category.

We used signal detection modeling of a large data set to show that forensic cartridge-case examiners were highly unlikely to commit false positives or false negatives but appear to be strongly biased against true negatives (Smith & Wells, 2024). Specifically, forensic cartridge-case examiners were far more likely to claim that the results were inconclusive when the shell casings did not match than to say the results were inconclusive when the shell casings matched. We presented evidence that some examiners were rendering inconclusives despite almost certainly knowing they were looking at actual nonmatches. Scurich and John's (2024) commentary on our article ignored this shocking finding and failed to treat inconclusives and nonmatches as separate outcomes. Scurich and John (2024) instead concluded that forensic examiners were not strongly averse to false positives and that examiners adopted different decision policies for different firearm brands. We show that the data contradict both conclusions. [ABSTRACT FROM AUTHOR]