Thursday, April 02, 2020

Where America didn't stay home as the coronavirus spread

https://www.nytimes.com/interactive/2020/04/02/us/coronavirus-social-distancing.html
NYT map shows percentage change in average travel last week; dark red is normal; orange is half of normal; lightest gray is no travel; outlined areas had stay-at-home orders, or guidance that amounted to a stay-at-home order, before March 27.
The New York Times has used cellphone data to show how Americans moved about last week, indicating that "Stay-at-home orders have nearly halted travel for most Americans, but people in Florida, the Southeast and other places that waited to enact such orders have continued to travel widely, potentially exposing more people as the coronavirus outbreak accelerates." Read more.

The map is based on anonymous data from 15 million people March 23-26, the Times reports: "Disease experts who reviewed the results say those reductions in travel — to less than a mile a day, on average, from about five miles — may be enough to sharply curb the spread of the coronavirus in those regions, at least for now."

The meaning of the data is not entirely clear. "The coronavirus outbreak is unprecedented in scale in recent history, and it is hard to know the exact relationship between changes in travel patterns and how quickly the virus spreads," the Times notes. "Other factors play a big role, including how quickly sick people are tested and isolated, how closely people tend to congregate — and luck. Sheltering in place is protective and clearly reduces people’s contact with others, but the existing evidence that the policy can effectively contain an epidemic within a large population is uncertain, experts said."

Here's part of a Times map showing when the average distance traveled first fell below two miles, limited to the southern half of the country, where travel has been heaviest. Not surprisingly, rural counties were less likely to fall below that threshold. For a larger version of the map, click on it.

No comments: