Tyler Cowen recommends a paper by David M. Cutler and Adriana Leras-Mooney on the effect of education on health.

The obvious economic explanations – education is related to income or occupational choice – explain only a part of the education effect. We suggest that increasing levels of education lead to different thinking and decision-making patterns. The monetary value of the return to education in terms of health is perhaps half of the return to education on earnings, so policies that impact educational attainment could have a large effect on population health.

I think this is a classic case of mistaking correlation for causality. Show me someone with good self-control, and I’ll show you someone more likely to be above the mean in both education and health.