The Epidemiology Bathtub: A Surprisingly Simple Way to Understand Disease Spread I’ll be honest — when I first started learning about epidemiology, I struggled. Trying to wrap my head around concepts like incidence, prevalence, and recovery rates felt like learning a new language. Then someone told me to imagine a bathtub, and suddenly, everything made sense. Yes, a bathtub. It sounds weird, right? But this simple mental model explains how diseases move through a population better than any textbook diagram I’ve seen. Let me walk you through it. The Bathtub: The Population Imagine a regular old bathtub. The water inside…