Figure 3
The scaling of economic productivity with city size and the generation of professional diversity.
(A) Superlinear scaling relation between total wages in US metropolitan (W(N) = W0N1+δ, with δ = 0.18 ± 0.03, in agreement with theoretical expectations of 
30). Inset shows the product A = wd versus city size, demonstrating that A it is on average independent of city size (R2 = 0.91). (B) The process of generation of new occupations as a function of city size: As the self-similar frequency distribution of occupations is pushed up by city size, latent occupations cross the lowest probability threshold and appear explicitly in D. The schematic shows how such a new explicit function (red circle) allow other occupations (yellow and green circles) to specialize further (acquire brighter colors), while remaining available to each other through network ties.
