false positives

The base-rate trap is the classic, and it is not academic: it is exactly how a high-accuracy fraud or disease classifier drowns ops in false alarms. The worked numbers, the tree you draw on the whiteboard, and the two levers that actually fix it in production.

A Type I error blocks a real invoice; a Type II error delivers the phishing email. Which one costs the customer more decides where you set the threshold. The spam-filter framing, the precision/recall mapping, and the asymmetric-cost call interviewers want.