American pandemic divide: Understanding the difference between linear and exponential growth

by Bob Schwartz

When it comes to attitudes toward the the pandemic, American divides keep cropping up. The latest is masks v. no masks. Then there are Democrats v. Republicans, blue states v. red states, trump v. no-Trump, fact v. fiction, etc.

I note today the most basic divide.

The virus follows an exponential growth pattern. One person infects two. Two infect four. Four infect sixteen. It is multiplicative.

It is does not follow a linear growth pattern, with each new infection adding more cases one by one. It is not additive.

If you don’t understand exponential growth, you don’t understand steep curves, peaks and outbreaks.

I would like to think that almost all American understand the difference between linear and exponential growth, and that a number of those simply choose to ignore it.

But I don’t think so. A number of American are somewhat innumerate, which is the number version of illiterate. American innumeracy is well-documented, though its causes are still an open question—whether a result of education or lack of interest is still debated.

Masks, distancing and other directives are essential precisely because the virus follows an exponential path. If people don’t understand that, that along with a general lack of social concern explains how we got here. And where we might be going.