United States · sunshine · 2023

Does sunshine change the links between county measures?

Every link on this site is worked out comparing counties alike in population density, household income and education. Here each link that holds up is worked out again with one more thing held equal: how much sunlight reaches the ground in winter, from NASA’s satellite estimates. If a link were only a difference between sunny and grey parts of the country, this would make it shrink.

Each figure is r: how closely two measures rise and fall together across counties, from −1 (one goes up as the other goes down) to +1 (they rise together). 0 means no link. Pairs with a weather or sunshine measure on either side are left out, since holding sunshine equal changes them for reasons that are about the weather itself.

Most links barely move

Of 1,875 links that hold up, 86 change by 0.1 or more when winter sunshine is held equal, and 0 point the other way. So for most of them, sunny and grey places are not the story. For the full method, see how the US figures are worked out. For one link that sunshine seems to explain but does not, see do sunny places have less depression?

The links that weaken most

These are the links most tied up with how sunny a place is. Part of what looked like a link between the two measures is a difference between sunny and grey regions.

The links that grow most

Here sunshine was hiding part of the link. Sunny places differ in a way that masked it, and once sunshine is held equal the link shows more clearly.