Big cities have a statistical advantage because the agglomeration of people, more intense social interactions, and better developed infrastructures invoke efficiencies and speed up the pace at which things happen. This is a worldwide, historic fact and does not much depend on what is particular or special in a given city, he says.
The researchers have shown, in fact, that with each doubling of city population, each inhabitant is, on average, 15 percent wealthier, 15 percent more productive, 15 percent more innovative, and 15 percent more likely to be victimized by violent crime regardless of the city’s geography or the decade in which you pull the data.
Remarkably, this 15 percent rule holds for a number of other statistics as well – so much so that if you tell Bettencourt and West the population of an anonymous city, they can tell you the average speed at which its inhabitants walk.
Scientists call this phenomenon “superlinear scaling.” Rather than metrics increasing proportionally with population – in a “linear,” or one-for-one fashion – measures that scale superlinearly increase consistently at a nonlinear rate greater than one for one.
A new way to quantifiably assess characteristics of cities and performance regarding different socioeconomic indicators (safety, innovation, productivity, walking speed, almost anything…). The cool thing is that its not just relative to other cities, but relative to what a city’s performance *should be* given its size.
![[Cover_Arctic]](http://si.wsj.net/public/resources/images/PT-AP884_Cover__G_20100917165515.jpg)
Image: Ray Bartkus 
