Wednesday, February 19, 2014

The incredible map that shows that half of the U.S. population produces half of the GDP

The map on the left (sources: 1, 2) is making the rounds in social media today thanks to the enthusiasm of some designers and journalists who should know better. For some reason, they think that it's surprising that large U.S. cities are responsible for generating 50% of the GDP.

So what? Is that insightful at all? According to the U.S. Census Bureau, more than 80% of the population lives in urban areas, and it seems that 40% 42% lives in the largest metropolitan regions (source), so this map is just revealing population density, among other sins. Just compare it to this population map, or to this other one, which is visually fancier, or even to this one, displaying concentration of college graduates. We should all work a bit harder in developing our 'numbersense' (h/t Kaiser Fung,) shouldn't we?

Side note 1: Perhaps this could have worked better as a cartogram?

Side note 2: This is a good time to remember this fantastic spoof by xkcd.

Update (02/20): Andy Kirk has storyfied the Twitter conversation and written a post about the map. I disagree with him (no sword-wielding either, Andy.) If the purpose of the map is what he describes, why wouldn't we just plot population instead of using GDP generation as a proxy? And, by the way, just to give you an idea of how tricky maps like this can be, it may be promoting a nasty urban vs. rural narrative: "Hey, we are the innovators, the creators, the producers, you redneck moochers!"

If you don't know much about the U.S., the map is even more misleading. If you're unaware of how large the urban population in this country is, you may end up thinking that people living in very large cities produce a disproportionate amount of wealth per capita.

All this said, Andy's post includes a very quotable passage: "One person’s ‘interesting’ is another person’s ‘knew it’." Good one.