Governor Doug Burgum gave a great discussion of the state of the problems in North Dakota right now during his March 15 press conference. The key point is the potential rate of transmission and the possible overwhelming of health care services. The fact is older Americans are more at risk (at least right now) from the disease. So the question many ask is, “Why close schools?”

I think I can explain it in just a few maps. This first map shows county population over age 65 in a given county as a share of the total state population.

The concentrations are not surprising and are not the main point to highlight. Look at the county population under age 18 as a share of total state population in this second state map.

You are correct. Except for the scale the maps seem pretty identical as far as where the concentrations are. Why is this important? It is important for the reasons the governor mentioned. The evidence suggests large concentrations of people present an opportunity for the virus to spread. It has the potential to spread in the younger population that would have fewer signs of illness. They can carry it and infect older populations very easily. This is the reason for closing the schools, to try and reduce disease spread and reduce the risk to the older population, that just happens to be located near to the concentrations of the school age populations.