With many cities, states, and countries asking people to remain at home, Google and Facebook location data is being used to help determine how many people are complying with the coronavirus lockdown…

Our sister site 9to5Google reports that Google is aggregating location data for 131 countries, measuring the drop-in visits to places like retail stores and transit stations.

Reuters reports that Facebook is doing a similar analysis in the US, including a guide to how many people are staying at home.

We’ll show trends over several weeks, with the most recent information representing 48 to 72 hours prior. While we display a percentage point increase or decrease in visits, we do not share the absolute number of visits.

Given the criticism both companies have faced over their collection of personal data, each is being extremely careful to avoid compromising user privacy.

In New York, for example, researchers found mobility dropped significantly on the weekends but crept back up on weekdays, when many people — particularly those living in low-income neighborhoods — are still required to work.

Apple is focusing on more direct assistance, with donations of cash and face masks to help fight the spread of the virus.

Facebook and the researchers leading the project say they have overcome [privacy] concerns by aggregating the data several times over and funneling it through academics. The researchers share broad findings with state and local health departments, which do not receive any raw data.

Although most coronavirus lockdown measures have been announced as a matter of two to three weeks at present, many health experts expect them to be extended to around three months.

Widespread availability of antibody tests, to show those who have had COVID-19, would allow a gradual return to normal once people are known to be non-infectious and immune, but the US, UK, and many other countries are being extremely slow to make these available.