Does money buy you happiness? Maybe not, but looking at this map, you might think it buys you health. This is the 2010 version of the Gapminder World Map. On the horizontal axis you have the wealth of all the world's countries in GDP. On the vertical axis you have the life expectancy in those countries. And it's pretty clear: Richer countries tend to have higher life expectancies on average. As Cliff Kuang notes: "there are almost no outliers from the general trend."

The danger of that map, however, is that it obscures problems within countries. Let's look at black and white Americans separately. Here's a chart, from Amartya Sen's fantastic book Development as Freedom:

This shows the survival rates for white American men and black American men, and compares it to the survival rates of men in China and Kerala, India (the data is from the 1990s). As Sen points out: When you just look at black American males, you see that they have lower survival rates than men in China and Kerala. And as it turns out, black American males are much richer than men in those places.

The point: Per capita GDP isn't the whole story when it comes to a country's health. And Amartya Sen's book is a great read if you want to understand why.