Greg Clark: The Law of Return: Is There a Physics of Social Mobility

1. y(t) = b y(t) + e(t)
2. b = 0.75 on a generational scale
3. Social institutions matter rarely.
4. Matters: isolated non-intermarrying elite.
5. Matters: assortative mating.

Conventional estimates of b (a) different, (b) vary with social institutions, (c) low enough to guarantee complete reversion in five generations...