Perhaps the 1% improve poor peoples' health?

A rather interesting little finding from over The Pond concerning the connection between inequality and the health of the population. Over here we've had Michael Marmot insisting for decades that health inequality is to be explained by economic inequality. And Wilkinson and Pickett have been shouting that they are not just connected but economic inequality is the direct cause of ill health for all. At which point we get the American study into health and inequality and we find something a little different:

Income inequality (as measured by the Gini index) was not statistically correlated to life expectancy, but it was in a positive direction (greater inequality correlated with higher life expectancy) and approached significance.

It is of course wrong to take a result which is not statistically significant and then claim that this is a significant result. Except, again of course, unless you make the correct claim about what is significant.

If it were true that economic inequality does indeed lead to the population keeling over like mayflies then we would expect to see it as a significant result of such a study. For they really were looking at the lifespans of rich and poor in the various different population centres of the US and seeing whether the local inequality affected those relative lengths of lifespans. We can't claim, not with any power at least, that inequality increases those poor lifespans for that result is not significant. But we can claim that the opposite, that inequality shortens those lifespans, is somewhere between not proven and wrong.

If it were true it should show up in this evidence. It doesn't: not proof perfect but highly indicative. Which is an interesting finding, no?

The big causes of variance in lifespans were the ones we might think of: smoking, obesity and exercise. Economic inequality just doesn't seem to be enough of a cause to create a statistically significant effect.