I went to a talk a few weeks ago by Richard Wilkinson and Kate Pickett, global health researchers who have written a book called The Spirit Level. They were quick to explain that, while the name makes perfect sense in British English, it has been a source of continuing confusion in American English. What is a “spirit level”? It’s a building tool, a type of ruler with little bubbles in it to show when it is parallel to the ground. Maybe it’s called a carpenter level in the states, or just a level when the context is clear.
I would have called it “Inequality vs Stuff”, or at least that’s my description of the talk: a vast array of scatterplots showing the relationship between income inequality and different measurements of population health. Here is one that is typical for their case:
When they told the story, they started with a composite health index scattered against inequality, since that has much less noise, and then use the noisy plots like this one as supporting evidence when they show that the relationship holds for everything.
The slide that stuck with me the most is one that diverged from their story a little:
Not population health this time, but still interesting. Something to share with your entrepreneur friends.
These plots seem like enough fun that I made my own, based on a question from the question and answer portion of the talk. I’ve forgotten who, but someone in the audience asked “How is inequality related to total fertility rate?” and the answer from Wilkinson and Pickett was along the lines of “We never thought to check, how do you think it might be related?”
Since I had the data lying around from my attempts to learn about model selection last summer, I made myself the plot. Turns out there is not much of an association.The only example of a non-association the speakers mentioned was a surprise to them: suicide rates are not correlated with income inequality.