How scientists track us to help tame Covid-19

A woman wearing a face mask checks her phone as she walks at the Naviglio Grande canal in Milan, Italy. Using your cellphone's physical location, a network of companies, academics and public-health officials are attempting to slow the spread of Covid-19 by analysing the data and sharing insights with governments in states like Massachusetts and California; in cities such as Boston, New York and Miami; and in other countries, including India, Italy and Spain. — AP

It wasn’t ordered up by Washington, it doesn’t have a catchy name and its members don’t get paid. But the Covid-19 Mobility Data Network could mean the difference between life and death.

The network sprang up voluntarily among universities, epidemiologists, public-health departments, database providers, advertising-technology companies and social-media giants like Facebook Inc. Their mission is to fight the pandemic’s spread by testing the effectiveness of stay-at-home and social-distancing policies using a single tool: your cellphone’s physical location.