According to the Times, “Roughly 5 percent of residents — or about 420,000 people — left the city between March 1 and May 1. In the city’s very wealthiest blocks, in neighborhoods like the Upper East Side, the West Village, SoHo and Brooklyn Heights, residential population decreased by 40 percent or more, while the rest of the city saw comparably modest changes.”

While a fair percentage of the departures were due to large blocks of student housing emptying out as colleges and universities shuttered, the paper’s analysis of neighborhood income levels indicated that the wealthier a given area, the higher the percentage of leave-takers.  The pace of departures also picked up significantly when Mayor de Blasio announced the closure of all schools in mid-March. 

Measuring the Migration

The article makes the point that while the data collected is certainly useful smartphone location data is imperfect. For one, “It misses people who don’t own a smartphone. It requires some guesswork about who is a resident rather than a visitor or commuter. It relies on the kinds of apps that track and transmit a user’s precise location. And it is unlikely to be perfectly representative of the general population.”

Other methods to measure quick changes in population on a large scale were also considered, along with data. The volume of household garbage collected by the Sanitation Department was also below average in wealthy neighborhoods, for example.