Epi Night School Lesson 1: What Is Epidemiology?

It's not skin medicine, that's for sure.

An angry anti-vaccine person online once told me to stay out of a discussion and “go take care of someone with eczema.” This was after I told them I was an epidemiologist. She clearly thought I was a skin doctor because of the “epi” in epidermis. (“Epi” means “upon,” as you’ll see later in the lesson.) Ever since, I wondered if people fully grasped what epidemiology is and isn’t.

If you don’t fully grasp the concept, you’re not alone. Epidemiologists certainly became well-known during the COVID-19 pandemic, but the science of how we do our work isn’t well-understood. You can see that misunderstanding when people think associations mean causation (we’ll get to that), or when they believe in fake cures because of misrepresented data.

So let’s start at the beginning: What is epidemiology, and why does it matter?