By James Kwak
It seems that social distancing is the primary strategy for slowing the propagation rate of COVID-19. That and widespread testing are the key tools for containing an outbreak, for reasons discussed repeatedly in the media.
But does it work? Or, more to the point, how well do different degrees of social distancing work? How strict does it need to be, and how tightly does it need to be enforced? It seems to me that this is an important and at least theoretically answerable question.
Thanks to ubiquitous commercial and government surveillance, there are staggeringly comprehensive databases of exactly where people are at all times. Google has one, for example. Picture for yourself an enormous aerial picture of some metropolitan area with a dot for every person’s location; then picture those dots moving around as time passes. That’s more or less what is available. (Some people are blocking their location data, and some people don’t have
personal surveillance devices smart phones. But there are certainly enough people transmitting their location to do the analysis discussed below.)